Originally posted by IThanos
After owning the SP4800 for a couple of weeks (returned it waiting on the SP4805) let me add a few comments
I can't wait for the SP4800 with its new 4x 6 segment colorwheel Im almost assured a perfect picture considering the very few annoying rainbows that I did see.

I guess this is the quandry everyone shopping for a new projector is facing. X1 is not acceptable to me, so do I pay up for a better DLP or get an LCD for similar price with MUCH BETTER resolution. The resolution is 854x480 on the SP4805 but 1280x768 on the Z2 or AE500. That is a HUGE difference. Sure you won't notice it with DVDs and tv, but you WILL notice it with HDTV. There are already a TON of shows in high def and it is growing very quickly. I would have to imagine Super Bowl in 1280 res in high def has to blow away the 8XX res regardless of DLP versus LCD. But since I have not yet been able to A/B compare, I have no idea off hand. I am eager to do some serious demoing of DLP with faster colorwheels to see if the rainbows are really less annoying.

Why are you DLP guys who aren't bothered by them so insensitive to other people? What if your best friend turns out to be someone who gets a migraine headache any time he sees flashing lights? You're gonna put your strobe light out for the party every time he comes over because you're not going to worry about the minority?

It's as if because you aren't bothered by it that it therefore must not be real and that you just don't care what other people experience.

Enough people on this forum report back that they are bothered by this that you must know this is a problem for a lot of people. I'm happy for you if you're not, but I don't understand the attitude that goes with it. It's a stupid 1st grade star bellied sneeches attitude.

In all honesty I think that most people who see rainbows are looking for them. Especially the one's that post on this forum.

If I ever do come across that "one" person in my life who reacts so badly to rainbows that they get migraines... I guess they'll miss out on the Super Bowl. I'm really sorry if I sound insensitive but the honest truth is that I haven't come across that person yet. And I don't think that I will.

I'm not having anyone from the AVS Forum over for the Super Bowl this year. Not because I don't like them, but because I don't want to see guys standing 4 feet from the screen looking for rainbows. I drove myself nuts looking for them as well, I got over it and they went away.

BTW, I thought the dog analogy was perfect. My friends know that I have a dog, the friends who are allergic still come over anyway.

You are probably right that most of the people HERE that see rainbows ARE looking for them. But I was a newbie last year and I wasn't and my wife had no idea what a rainbow or a dlp or a lcd was, and she spontaneously reported them within a minute or two. So I know it happens.

jacksonian, I know it happens as well. But you almost seem mad at the rest of the "rainbow free" world.
I also think that you're feeling that we all must have ran across someone else who has a problem with rainbows. If I didn't count anyone from this forum... it would be 0 people for me. (out of over 50)

Not bad.

There are plenty of other people here who have had the same experience as I. Most of my friends think I'm crazy whenever I bring it up and my wife still hasn't seen a rainbow on either of our 2 DLP's... and I've tried! (Not counting the spoon in front of the lens trick.)

Funny thing though, she saw them on a store demo with the X1. This is why I believe that the setup can at least help.

No, I'm not mad at you guys. I'm envious that I can't seem to enjoy the blacks that you guys can get, but I'm not mad. I does bother me though when people act like some of us are making this up just because they haven't experienced it personally. Plus it's usually followed with some wine and cheese type comments about how dlp is for more refined viewers that prefer a film-like image while us lcd folks are beer and wings people with our screen door and poor contrast. That's all.

I'm with jacksonian on this. Honestly, a lot of DLP people here seem to have the attitude that, yeah, I see rainbows, but it's not that bad, stop worrying about it and watch the movie. Obviously you are less sensitive than some of us.

But for some of us it is bad. When I watch something with high contrast scenes (especially black on white or vice versa), if I move my eyes even the slightest to follow a scene change or moving object, everything around where I'm looking rainbows. Big rainbows, a big long vertical streak of them.

Example: Gandalf's torch in the Minas Tirith scene towards the beginning of FOTR (my favorite movie ever!) when he goes down the steps to read through the accounts of Isildur. His torch is not white for me. It's one big fat moving rainbow. Seriously. If you saw stuff like this constantly it would drive you crazy too. Maybe some of you see his torch white, maybe some of you see it white with a little teeeeeeny bit of rainbowy effects around it. For me it's only white in the very middle (like 35% of the torch). The rest of it is a rainbow of colors.


I think the reason there's no lawsuit or anything about it is because Samsung, etc quickly replaced its low-speed DLP RPTVs with higher speed wheels - I can't see rainbows on the current DLP RPTVs unless I TRY, and TRY HARD at that. 2x is a different story. So I'm not giving up on the technology, just upgrading.


P.S. My fiancee knew very little about rainbows and sees them reguarly yet infrequently, and not too big, on the X1 - scenes were I say "Arrrrgh rainbows everywhere" she can't see any at all.

I got a Sammy HLN437W a few days ago and the picture is stunning, especially in HD. I admit to seeing rainbows on SD on a regular basis, but especially when I'm thinking about them (and unconsciously looking for them). It seems that after a whole day of enjoying the TV my eyes get rather tired and that's when I start seeing more rainbows. However, I rarely see them when I'm interested in the show I'm watching and almost never while watching HD programming. I believe that seeing rainbows happens for me only when my eyes decide they're bored with the programming (I never get bored with an HD picture, no matter the content). I don't think I get any more eye strain or headaches than I used to when I watched CRT TV all day long. I think I just need to pry myself away from the TV once in a while and the rainbows and eye strain will go away.

I'm sure it doesn't help that I'm also staring at the computer screen when I'm not staring at the TV ;)

I did a side by side comparison of an X1 and an older LCD from infocus. Since I liked the picture from the X1 (rainbows and all) better than the LCD projector, I used the X1 for the Super Bowl. Had 14 people over. Not one mentioned the rainbows or headaches (I didn't ask of course). They all loved it and thought it looked fantastic. I convinced many that it would be silly to buy an expensive rear projection set after seeing front projection.

For me though, the rainbows and eye strain (particularly from constantly looking back and forth between conversations with guests and the game) were pretty bad. I definitely will not keep the X1. But I just wanted to report my full experience. I will try DLP with faster color wheel and I suspect it will be fine for me, but still not convinced yet I wouldn't be better off with a higher resolution LCD for the same money or even less.

trader, have you seen anything like the Panasonic 300 or Sanyo Z1 LCDs?

While I have learned a lot from this thread, too many people are spending way too much time arguing over how many people see rainbows and whether it is a real problem or not. It takes forever to pick through all the stupid bickering to get any really helpful information. So give it up and start concentrating on advice for those who see them.

I recently purchased a BenQ 8220 DLP projector. I did not see any rainbows on the factory default settings. But when I increased the contrast and brightness in an experiment, I saw a lot of rainbows. They were very, very bright and bothersome and would have caused me to return the projector asap if that was the normal image I saw. But they went away entirely when I returned the settings to the factory defaults.

I had a lot of people over for the superbowl yesterday, and for selected portions of some DVDS. I did not see any rainbows. Nor did my wife who also sees them on certain set ups. And not one of my guests complained of any headaches, rainbows, etc. And they were there in part to critique my set up.

So, yes Virginia, rainbows exist. Some people, including me, are very, very bothered by them, and no, I don't see any with my projector, at least when I don't turn the contrast and brightness up beyond where it should be.

So how about the rest of you stop arguing about the existence of rainbows and their effect and telling people what settings they should use, what projectors they should buy, and what else they can do to avoid rainbows if they want to have a DLP set up rather than an LCD or other set up that has its own, separate, problems.

Originally posted by jacksonian
trader, have you seen anything like the Panasonic 300 or Sanyo Z1 LCDs?

No, I'm considering the Z2 and A500 but haven't seen either one yet.

RE: How to deal with rainbows -- don't get bent out of shape. The techniques for dealing with them are pretty obvious. Properly calibrate your projector using a setup DVD (AVIA or whatever) and try to not dart your eyes around too much. When walking around, turning head, getting up or sitting down, either don't look at the screen or close your eyes until it is out of view. Or get an LCD :)

Tnilsson, good post. I've tried to get insight into brightness/contrast as a factor in the degree of rainbow effect, especially after I read a post from someone who used a ND filter to get rid of rainbows. But I was just told to demo a pj before I bought one. Hmm.. really? Never would have thought of that.

I think its a bit of a fallacy to say that most people who see rainbows only see them because they are looking for them. I'm lucky enough on a 4x wheel i don't see them even when i am looking for them but i know when i first gave a 2x speed dlp a chance i saw plenty of rainbows and i tried as best as i could to forget about them. To tell someone they have to sit perfectly still and not let their focus change is silly. Movies force you to change your focus and you cant possibly stop yourself from letting your eyes blink and move. I don't see them on my current 4x dlp but i would never deny someone who does.

I'm curious to how many posters who claim rainbows don't exist unless you search for them will gladly teach an lcd user to find vb?

oh well what can you do.

velvetpoet,
I'm no expert, but the more I read, the more I tend to believe that the rainbow effect is the result of a combination of things: sequential color, brightness, contrast, viewing environment, etc. The fact that you don't see them on a 4x and you did on a 2x reinforces my belief. So, it could be that eliminating or adjusting just one of the contributing factors will lesson the problem for some people. (That's a guess, not a pronouncement.)

I was ready to pull the trigger on the Marantz S3 DLP, but after viewing the Samsung 5?" rear projector on Sunday, it has me so scared of seeing tons of rainbows that I may never recover. I went to the store 100% intending on taking the DLP home, since the 46" version fits perfectly in our armoire, but the rainbows were absolutely unbearable!!!! Is this just the Samsung or is it indicative of many displays? How fast is the samsung's color wheel?

As far as the Samsung, information I gathered said they were effectively 5x. You might be one of the unlucky ones - I've sat at BB & CC and am able to see rainbows on the Samsungs if I try REAAAAALLLY hard.

Bump.

I looked through this thread and couldn't find the info that I was looking for, so maybe you guys can help me out. This is a question ONLY to those who are sensitive to the rainbows and can tell me about your experiences.
I see rainbows frequently on a 2x DLP. How much of an improvement, in your opinion, is it when you move to the 3x or 4x wheel speeds? I really like the Picture Quality of the DLP's, but the rainbows drive me nuts when I try to follow a scene or my eyes scan quickly from left to right. I haven't had the chance, and I probably won't have the chance, to try a 3x or 4x projector, so before I buy, I need your advice. I'm not giving up on DLP, I just want to make the best possible effort to get one that won't show me very many rainbows when I watch a DVD movie.
Thanks guys. Right now, I'm thinking about the PB6100, PB6200, the H30 or the Panny AE-500. I'll probably end up with the PB6200 if the 3x wheel speed helps quite a bit.
Thanks again.

I see rainbow on 5700 every minute (it is a 5x color weel), but very very rare on z90 (same 5x color weel). Very strange.

I've posted this before, but I'll recap my experience for you.

I'm the most sensitive of me, my fiancee, and my friends to rainbows. I'm returning my X1 and waiting for the 4805.

I tested out a Marantz $11,000 projector (5x wheel) and couldn't see rainbows. Samsung DLP RPTVs @ Best Buy, Circuit City are also 5x as far as I know, and I can see them only a tiny tiny bit if I purposely try to. Try checking out those RPTVs at your local BB, CC.

My biggest problem is whites - I think the RGBW wheel in the X1 is my problem. I'm crossing my fingers that the 4x on the 4805 will close enough to 5x performance.

what will the street price for the 4805 be? i just purchased a 6100 (happy as hell with it BUT i do see very few rainbows but they are there) and if its similar in price i might return my pj and wait for the 4805.. what do you guys think?

I've seen many, many DLP projectors and been lucky enough to never "really" see a Rainbow... until today.

I sat down with 3x DVDs, 2 darkened rooms, a InFocus 5700 and 7200 projecting on Firehawks.

One of the DVDs was Dark City. I saw several rainbows in the first 10 minutes of the movie, 5-6 in the nightclub sequence that introduces Jennifer Connelly's character alone (Starts Chapter 3). The nightclub is only about 30 seconds long and I think is a great test to see if a projector will work for you- high contrast, black blacks, and a smooth well-mastered artifact free image. Not the DVD to use to check for color, choose something else for that.

I was significantly annoyed by the rainbows. So annoyed that I'm thinking my next projector might be LCoS. At the very least I'll want to demo that same 30 second section again on any DLP I might consider.

I.

I have better than 20/20 vision and I dont see them on the X1 no matter how hard i try. Same with my friends and family. I know they exist but as long as I cant see them I am happy. People need to stop telling others to try and find them for proof. IF you see them fine buy something different. If you dont enjoy it and move on.

When the X1 is in Theater Mode, it doesn't use the WHITE part of the wheel, it makes it black...so if switching the X1 into Theater Mode doesn't help you with the rainbows, then I don't think the white will have anything to do with it. Your vision has nothing to do with it. If you are looking directly at the screen, you wont' see them. It's when you "scan" from left to right, up to down, or turn to talk to someone and then look back, that's when you'll see the rainbows. I mean, don't GO LOOKING for them, that's opening a Pandora's box, in my opinion. I was at an Audio HiFi place today and taught the salesperson how to see the rainbows on the $6000 Samsung DLP TV that they had in there. I'm not giving up on DLP. I'm going to give 3x and 4x a chance, I might even give the 2x Theater Black mode a chance on the X1, but I was hoping to start off with an XGA or higher projector.

I have tried very hard to see them like a fool. Still never saw them on any video mode on my X1. I do watch everything in film mode. I play Xbox in FIlm mode also and it looks like my old Sony tube screen. I never could see myself using presentation mode. It crushes white bigtime.

Does anyone have a complete (or fairly complete) list of projectors and wheel speeds other than the small list right above?

I have the opportunity to view a Dell 3200MP (DPL wi 2x color wheel). Which of the following movies should I view to determine if I am susceptible to rainbows:

Matrix I or II
The Hulk
Spiderman
LOTR I or II

Thanks

Originally posted by ctbrown
I have the opportunity to view a Dell 3200MP (DPL wi 2x color wheel). Which of the following movies should I view to determine if I am susceptible to rainbows:

Matrix I or II
The Hulk
Spiderman
LOTR I or II

Thanks

From everything I've read, it seems most people complain about rainbows in the "fog" scene at the beginning of Pirates of the Carribean, and in the moving torches during the underground scenes in Lord of the Rings I. But to me, any movie would be sufficient to tell me I can't stand a x2 DLP projector.

So far me and my whole family and every one of my friends cannot see rainbows on my X1. We have even gone out of our way to try just to make sure. Of course my friends finding out they are immune went out and bought the same unit. Infocus should give me a cut.

Well, i've almost had my X1 for a year now.. and i can say i NEVER see rainbows anymore. I dont know if its because my eyes have adapted to it or something happens to the projector after a certain amount of time. But I cannot see rainbows.

When i first got it i saw them all the time, but they did not bother me that much. Now i use my projector for about 95% of all media and gaming and I never see them.

Just my input.

Matrix II. One of the first scenes when Neo is fighting the Agents. you'll see it all over if you are susceptible.

Have X1 in local sports bar about 8 months now, and never anyone mentioned rainbows.

Have had an X1 in my home now for about 6 months and same thing.
No rainbows reported by dozens of viewers.

Originally posted by RobsTV
Have X1 in local sports bar about 8 months now, and never anyone mentioned rainbows.

Have had an X1 in my home now for about 6 months and same thing.
No rainbows reported by dozens of viewers.

Where abouts in the area? I am only 15 minutes outside of New Port Richey and never turn up and opportunity to go "demo" a projector ... especially if it is in a sports bar!:D

(X1) I saw them early on, but don't anymore. I told my son about them at the outset. We watch the projector at least 100 hours / week (over a 1000 hours of watch time for him). He's still looking for them.

Fired up my new NEC HT1100 last night with the Matrix Reloaded. 3 people were watching. One person saw rainbows (hundreds) to such an extent that he had a headache at the end of the movie and had to leave. Myself and 2nd person saw no rainbows at all - just fantastic picture.

Obviously some people are extremely sensitive to this problem- no matter what speed the colour wheel. The caveat therefore is Before you buy ANY DLP projector, ensure you are not one of the unfortunate people who are sensitive to this phenomen.

Mookoid, I bet if your friend toughs it out and comes back again (BTW, Matrix Reloaded is about the WORST movie for rainbows) he'll get used to them and even stop seeing them eventually. It's worth it for a screen that size. LOL

Yea just tell him to stare straight ahead and stop looking around the screen! :)

.

It would be a good thing if this was the thread that was linked in the forum rules. (It is not at this moment) The rainbow link provided there is an old one and is not the one the moderators (and most of us) would like to see used.

FYI

Done. You can find it in the Forum Posting Guidelines & the FAQ.

I used a 86 x 86 inch screen and we were sitting very close (too close) so my friend had to move his head around to see the image. I think this contributed to his problem. The 2 other people seated at same distance had no problem at all though. I did notice another thing though: When the image was fairly static it was extremely clear and sharp. However when there was movement things got a bit blurry. Movement was not smooth and images were not clear when moving. Is this a function of DLP projectors in general or just a setup issue? Any ideas anyone??? I will experiment further this evening...

Count me in on the "sees tons of Rainbows" side, but also add me to the "gets incredible headaches watching DLP" team too.

It's incredibly unfortunate. DLP gives a phenomenal picture quality - but those rainbows and headaches are not something I can overcome.

Here's what happened: I got my X1 and was immediately blown away by the PQ. Absolutely amazing. I was trying out DVD after DVD in wonder at the picture, when I began to feel a strong headache coming on.

Now, I'm not prone to frequent or severe headaches, short of dehydration. So this was odd. I wondered if I was tired or needed more fluids or what... However, I began to notice that this headache seemed to be concentrated at the back of my eyes (if that makes any sense).

After a while I put Matrix Reloaded into the player and saw MASSIVE rainbows appear (to my surprise, as I'd forgotten to look for them). After that I saw them everywhere, but said nothing to my wife, who was also watching. I tried shrinking the picture, holding my eyes still (I'm a natural "eye darter" - my eyes dart around the screen). All the while the headache getting worse and worse. My wife left after 1/2 hour complaining that the size of the screen (I only had it at about 70in) was giving her a bad headache. I became suspicious at that point that the rainbows and headaches were related.

As the evening wore on, I found myself surfing the web on my PC, which is in the same room - I was really looking at the monitor rather than watching "The Two Towers" just to get a rest from the headaches...

The next day I'd had enough and took the X1 back. As soon as I told the salesguy I was seeing rainbows and getting headaches he nodded and said it wasn't a surprise to him.

I picked up an Epson S1 to try.

Now, the S1 is no X1 in PQ, I'll say that right off the bat.

Its not bad, but it lacks the visual punch of the X1, and naturally the S1 has much more screendoor (as well as some VB). However I switched it on and gave a MASSIVE sigh of relief at the picture - my eyes didn't hurt, no headaches, and NO RAINBOWS.

I now have the screen at about 86in and we watch every movie we rent/buy on the S1. No headaches for me, none for my wife (it wasn't screensize, it was also the rainbows as she later asked me "what were those color things?").

(Side Note: It was the X1 or S1 for me as both are about $1300 cdn and available in Canada from places with good return policies. The Z1 or Panny 300 are at least $500 cdn more, with 15% restocking fees. Z2, Panny 500 are WAY out of my price range. Most others in the usd $1k range, including the Epson Home 10 and Hitachi Home 1, are simply not readily available in Canada).

X1 picture quality = 9.5/10
S1 picture quality 7.5/10
Not seeing rainbows and getting headaches... priceless.

I now recommend to anyone who will listen:

Go buy the X1 from a place you can easily return it to with no restocking fee. Watch a variety of movies with the people most liekly to watch with you (spouse, kids, roomate, whatever). If after a week of movie watching you are all happy - keep it and enjoy! If however you get headaches or are bothered by rainbows - welcome to the LCD world my friend.

Side note for comparison's sakes: I get a mild version of the headache and see fewer rainbows on the 5x DLP RPTV I demo'ed. So I'm likely out of the DLP market until either a) 10x color wheels, or b) 3 chip DLP in the $2k range. (i.e. see y'all in 2008).

I'd really like to see folks explore the "technical" aspects of this. Seems that we spend a lot of time jabbering about I can or cannot see rainbows.

I'm in the midst of building my HT, and just got the X1. (love it) I occassionally see a rainbow, but the more I watch the less I notice them.

What I would LOVE to read here is more about what might possibly help reduce the effect. I plan to have friends and family over for a night at the movies often. Of course I would want to insure I've done everything possible to make their viewing enjoyable.

I have questions that I don't see anyone asking. Things like:

Grey screen vs white screen. High gain vs low, neutral or negative gain.
Ambient light.
viewing distance
Height of screen .. angle of view. And how all these affect the rainbow effect.

The point is, instead of just running on about this with no valid input, how about we take some notes here? The guys at the "Screens" forum have contributed a lot by making tests and using all kinds of variations to come up with some incredible DIY screens.

Let's compare notes .. experiment and who knows? Maybe this "effect" can be reduced or even eliminated for some of us.

For what it's worth, since I'm in the middle of the HT construction I plan to do some "testing". For example, I already know where I can see the effect every time in a movie. This was with a pure white screen, in a totally dark room with a floor mounted PJ. I've noted the seating position, angle of view etc. Next will be the permanent mounting of the PJ to the ceiling. Again I'll test with the same movie from various angles and ambient light etc. Well you get the idea right? If I find anything I'll post back here.

I welcome anyone else who has actually attempted to reduce the effect to please post your experiences as well.

Oh there's lots of ways to reduce rainbows.

Some of the most effective ones are to show a monochrome movie (either red, green or blue), speed up the color wheel, or simply turn the projector off :).

Hope this helps.

Went to a home theatre store yesterday and the salesman claimed to be demoing a 6x color wheel unit (that doesn't exist, right? 5x is the maximum so far I thought) and I saw rainbows. Guess that rules them out for me, huh..

By the way, Electrified Discounters, where I bought my Mitsubishi XD300U, apparently refuses returns completely. So, now I've gotta try and sell it, as I can't afford a $2500 boat anchor :(..


http://leif.cx/dlplogo.gif

///Leif

I am very curious of the underlaying course of the bad effects of rainbows. I think it is not the matter of seeing, because I have seen post of people getting headaches at even 5 speed wheels. There should be more to it. It is not the matter of seeing it, but the matter of how it affects your connection from the eye nerves to your organ of balance. I find this interesting. So my questions to the people badly affected by the rainboweffects:
Are you also bothered by crt monitors with 60Hz, 75Hz or even 85Hz?
Are you able to read a book (bending a little forward) in moving car, train or bus, that shakes a bit?
Are you very susceptible to cold of heat change?
Are you sometimes affected by nausea, vertigo or headaches?
Ever been in a rollercoaster atraction or other things like that in an attraction park (like disney etc)?
Ever seen the 2 horizontal wires in sony-like trinitron monitor?
Are you bothered by death (sub)pixels in tft-monitor?
Are you bothered by bright moving lights in a disco? (is there any difference after a couple of beers or wine?) (last one is a joke of course)

Also, I am very curious if there are more solutions to help these people, to reduce the effect.

infinitatus:

<-- Bad rainbow sufferrer here, plus headaches (see my previous post).

To answer your Q's:

Q/ Are you also bothered by crt monitors with 60Hz, 75Hz or even 85Hz?
A/ 75Hz is tolerable. Any lower and my eyes hurt.

Q/ Are you able to read a book (bending a little forward) in moving car, train or bus, that shakes a bit?
B/ Yes - no problems there.

Q/ Are you very susceptible to cold of heat change?
A/ No, not that I'm aware of.

Q/ Are you sometimes affected by nausea, vertigo or headaches?
Nausea - no. Vertigo - sometimes at precarious heights. Headaches - only from dehydration or this rainbow effect.

Q/ Ever been in a rollercoaster atraction or other things like that in an attraction park (like disney etc)?
A/ Heck yeah I love 'em. Rode every coaster at six flags twice in one day once. I never get motion-sickness.

Q/ Ever seen the 2 horizontal wires in sony-like trinitron monitor?
A/ Yes, if I look for them. Not really a bother though.

Q/ Are you bothered by death (sub)pixels in tft-monitor?
A/ I have no idea what this means.

Q/ Are you bothered by bright moving lights in a disco?
A/ They are annoying, but they don't give me a headache or anything.


For me, the headaches were constant, whether I was actually seeing the rainbows at the time or not. Simply watching 2x DLP gave me headaches. Looking away made me start feeling better.

As for rainbows, I see them everytime my eyes move about the screen. That is the key. As I'm a natural eye-darter, it was constant in any kind of scene (worse in some).

Infinitatus,

> Are you also bothered by crt monitors with 60Hz, 75Hz or even 85Hz?

I can percieve flickering below 85hz, but I can also get used to it. At a convention years ago I had to run my monitor at 50hz (!) to make it compatible with a PAL projection system, and I actually got used to this without it giving me a headache.

> Are you able to read a book (bending a little forward) in moving car, train or bus, that shakes a bit?

Absolutely.

>Are you very susceptible to cold of heat change?

Picky about temperature, yes I suppose, but it doesn't give me headaches or anything :).

>Are you sometimes affected by nausea, vertigo or headaches?

Everybody gets headaches once in a while, but no more often than usual for me. Nausea/vertigo, nope.

>Ever been in a rollercoaster atraction or other things like that in an attraction park (like disney etc)?

Yep, I love'em!

>Ever seen the 2 horizontal wires in sony-like trinitron monitor?

I see them if I look for them - not an issue though.

>Are you bothered by death (sub)pixels in tft-monitor?

Not at all, I only see them if I look very very closely.

>Are you bothered by bright moving lights in a disco? (is there any difference after a couple of beers or wine?) (last one is a joke of course)

No, I love them. I'm not really affected by strobe lights either. And yeah, there's a difference after a couple of drinks - if there's also house music playing, I have great difficulty standing still :).

My theory why the rainbows are so distracting for me is that while i'm expecting (or looking at) a solid pale colour (like white), all of a sudden i get an extremely bright fully saturated flash of light. If an RGBW colour wheel was used in a different manner (i.e. use white as much as possible, not because of brightness but to minimize the use of the other colours), maybe it wouldn't affect me so much. This is all guessing though.


There's gotta be a better way to do 1-chip DLP. What if they upped the pixel count significantly (4-fold) and coloured individual mirrors red, green and blue? (much like the CCD in a digital camera)

I suppose this would be much more expensive, but you'd save the expensive optics of a 3-chip DLP.

A setup like this would have constant conversion error, but so do LCDs.

What about a 3-chip DLP with three lenses? You'd have the pain-in-the-ass calibration like on a CRT projector, but it would still be easier since DLP panels don't change is size/shape. This would also save the expensive optics that make 3-chip 1-lens DLPs so expensive, I believe.

///Leif

Went to a home theatre store yesterday and the salesman claimed to be demoing a 6x color wheel unit (that doesn't exist, right? 5x is the maximum so far I thought) and I saw rainbows. Guess that rules them out for me, huh..


yes there are 6x (also known as RGBRGB) and the new HD2+ are supposed to work with a 7x as well.

Hm.. What's with these minor incremental improvements?

It's a colour wheel, how hard can it be. Why don't they just make it 15x and be done with it? (I read somewhere that 15x will be imperceptible even to figther pilots - they actually tested).

///Leif

http://leif.cx/dlpsmall.gif

it's not the wheel, but the mirrors. They could use a turbo engine on the wheel, but if the mirrors aren't moving fast enough, or the processor can't move them fast enough then what good is it that the wheel is spinning faster?

The answers to your questions are no. Refresh rate doesn't bother me at all (I never see a flicker). Ditto with the other questions. But I find a lot of the rainbow sufferers on messageboards comment that they do get fatigued by low refresh rates, so there is SOME correlation there.


I find that a lot of heavy gamers see rainbows. Just a pet theory so far. I find a lot of agreement with it. Nongamers so far have no idea what I am talking about. They seem to be immune to the effect.

Let me explain my questions. Some of them were to distract you from the subject and they don't explain anything, but others do.
First of all, let me tell this: I have never been able to compare an lcd projector to a dlp projector (there are no dlp projectors for sale in my town or in the neighbourhood) So, I am not judging here. But according to all your posts, I extracted the following: I see four groups here (I know it is a bit general).
1. You don't see RBE. (maybe you don't know what it is, or you didn't have any aid to see them (I never saw the 2 horizontal lines in a diamontron/trinitron monitor till somebody helped me))
2. You see RBE, but aren't bothered by it.
3. You see RBE and are bothered by it. But you don't get fatigue eyes, headache, nausea or vertigo.
4. You see RBE and are bothered by it, you get fatigue eyes, maybe a headache or even vertigo and nausea.

I think the persons of the last group are also ore susceptible to things that easily can trigger nystagmus or make you sick. These persons are driven mad (ok a bit exagerated) by certain flashing lights or moving objects. E.g.: I can't read in moving car bending a little forward; 75 Hz or lower monitors drive me mad. I get a headache or even nausea. I tend to believe that RBE for some people (fortunately very few) can trigger these symptoms in a similar way. Up til now I can't proof this theory, because I still have to see my first dlp projector and even then, one person is not enough to prove a theory. So I need answers of you. Because if this theory is true, the people of the last group will still be bothered by RBE, even with a highspeed wheel. You will come at certain point then, that you cannot actually see any RBE, but the flicker frequency still remains, enough to give you a headache like a 60 Hz monitor. I hope, I am wrong :(

Rich A,
I agree with you. Some months ago I tried to pose some questions to start a discussion about ways to diminish the R-Effect, but had no luck. As for me, I have never seen a rainbow and I've seen several DLP projectors. My worry has always been the fact that we like to have movie nights with various friends, not the same ones each time. So I've wondered if I had a friend over who saw rainbows, would there be anything I could do to help diminish them that evening. Especially since someone posted that they eliminated rainbows by installing a $20 neutral density filter.
All I've been able to deduce from sources on the Internet is that the combination of sequential color, contrast and brightness causes rainbows, as far as I can tell. Then combine that with saccadic eye movement and you have a recipe for rainbows. There have been lab experiements with subjects watching a spinning cylinder with black and white vertical stripes, and some of the subjects experienced nausea. Some people have reported that turning on a few lamps in the room reduced rainbows, or turning off the white segment. The point is, that if rainbows are caused by a combination of things, then eliminating one or more of the contributing factors could diminsh the problem, in theory. If DLP projectors excel in contrast, then perhaps there is room to reduce the contrast to lesson the rainbows. If a DLP projector has high lumens, perhaps there is room to reduce brightness to lesson rainbows. Of course, I'm merely suggesting temporary measures to try for the benefit of a guest.

Originally posted by jimnc
Rich A,
I agree with you. Some months ago I tried to pose some questions to start a discussion about ways to diminish the R-Effect, but had no luck. As for me, I have never seen a rainbow and I've seen several DLP projectors. My worry has always been the fact that we like to have movie nights with various friends, not the same ones each time. So I've wondered if I had a friend over who saw rainbows, would there be anything I could do to help
<snip>
temporary measures to try for the benefit of a guest.

Ah exactly my point. I'll be experimenting with every aspect .. trying to find a balance where I get the best quality picture with a tilt toward reducing the RBE. I've designed my HT room layout so I have a lot of leeway. The screen is shadow-boxed and even with the ambient light high in the room, the actual screen area is very dark. So I can play with ambient light levels. I haven't mounted the seats yet so I can also play with positioning. Of course brightness, contrast etc. are also to be looked at. Last will be the screen itself. Right now it is a pure white with a slight matte finish. Still more glossy than I'd like. Before I start the wall painting etc., I intend to give the screen a treatment using the Misty Evening paint colour as described in the "Screens" forum.

To date .. I've confirmed the following. Distance to the screen (lessor is worse) I found when too close with a large screen the eye tends to wander and that is where it shows up. Moving back a few feet actually reduces the instances when viewing the same movie. I attribute that to the fact that my eyes are not moving horizontally that much at the greater distance..

Anyway .. some will say it's really an "Optical Dillusion". :p

I have a friend who is an optomitrist. I know he often makes custom tinted glasses for people who are affected by bright lights and other things. It might be interesting to get his take on this. Who knows? Maybe all you need to do is to put on a pair of slightly tinted sunglasses. <grin>

More later ..

Who knows? Get a pair of polaroids and watch the movie:cool:

Originally posted by infinitatus
Who knows? Get a pair of polaroids and watch the movie:cool:

This might be something believe it or not. Today my son came over to get a "sneak preview" of the semi-finished HT. We sat down and discovered that he could see the rainbows much worse than I could. He said it didn't bother him and he could ignore it. But we both see different amounts viewing the same picture. His is more pronounced than mine.

He had to run out on an errand. When he came back I restarted the movie and we both sat down to enjoy it. After 5 minutes he exclaimed, "What happened to the color thing"? (rainbows) He suddenly couldn't see them any more. Huh? Then we realized he had come in from outside and still had on his sunglasses. He has some kind of fancy prescription glasses that have very little tint but a fair amount of polarization. I believe they are a very light grayish tint.

Anyway, he watched with them and without them. Lots of rainbows without .. nothing with. Now this may be specific to his eye/brain/focus thing. I wear glasses myself, but have no prescription sunglasses. Rather just some clip-ons. I tried one myself. Gad-zooks .. seems to work. Not 100 percent in my case, but almost gone. I'll have to sit down and ask my son just what kind of tint etc. his glasses were. Maybe I'll get myself a prescription set made up and see what happens.

He also said that the effect was more pronounced where I still had a "hot spot" on the screen. (I haven't painted it yet and it's still a very shiny white) I'm hoping the Misty Evening paint treatment will help reduce the hot spots. But since he sees them more at the hot spot, I guess there is some sort of correlation involving the reflectivity of the screen and rainbows.

Being an amateur photographer, I have a bunch of fancy filters. I'll have to dig out my circular polarizing filter (looks about the same size as the X1 lens) and see what effect that has. Normally in photography a "circular" polarizer is used with certain types of digital cameras. As opposed to a linear polarizer. I have often used it to reduce or remove glare from brightly reflecting surfaces or to shoot through glass while removing the normal reflection you'd get off the glass surface. It will also enhance colors in the blue spectrum, and is sometimes used to bring the blue sky to a more vibrant color. I think this has some merit.

Has anyone experimented in this area? I would be surprised if not. I think the solution may be to get just the right amount of polarization with a very slight gray tint. So as to not darken the picture too much. If this really works out .. maybe it's something the DLP manufacturers should look into .. might be solvable with a fancy filter ??

Now I kind of doubt this is a solution. I think the fact that some see them and some do not and even some can be made sick from them is fact that it's going to be different for everyone. But hey, if it works for even a few, well that's good no?

More later after I confirm a few things.

Jcebedo had an X1 with optical filters and I believe that it not only improved color but also reduced the possiblity of rainbows simultaneuously. This was my assessment when compared to more expensive projectors at last years Bay Area Shootout in Vallejo. However the downside is that the X1 is even more dependent on light control than before since overall light output is reduced by those filters. If you are projecting in controllable lighting conditions the X1 will still be of very good value and the pronouncement of rainbows would probably be less. The size you'll want is 62mm.

victor-eyd - Thanks for that info. My environment IS very controlable. I can make it almost pitch black during normal daylight hours. But I also have the screen mounted recessed in a shadow box about 12 inches back from the opening. This makes the actual screen area even more dark than the rest of the room.

I'm encouraged by your comments. All my filters are either 52 mm or 82 mm. I've got a few big high end lenses. Not a lot of filters for the 82 mm ones though as they generally cost a bundle. Just a skylight and maybe a neutral density.

Do you have any information as to what filters he was using? There's a large camera "swap fest / flea market" that comes to town every several months. Lots of good used bargains. If I can wait until the next one, I may pick up a few various types in the 62 mm flavor.

Thanks again for the info ..

James had 3 filters: First one is ND8x filter, 2nd is skylight, 3rd is the 81a yellow filter, all attached via thick rubber bands- the ones you find in the produce section. Technut also commented in his FAQ on another user using a ND2 filter, and I've read another using a polarizing filter. It did produce the intended effect of reducing rainbows but at the expense of brightness. But since you have a light controlled room it should work for you.

Originally posted by Rich A
This might be something believe it or not. .
Sorry Rich A, I didn't mean to make a joke about it. I also believe, that a polarized filter could reduce RBE's. It has been along time ago, since I had fysics (optica) in highschool. But if I remember well, a good polarized filter does the trick only in one plane (horizontal/vertical depending on how you rotate the filter). So it reduces the effects only in one plane (and colors too?). If you put 2 well polarized filters, the second 90 degrees rotated from the other, your RBE will probably be eliminated and so is the the whole picture, you will have a black screen. So if you rotate a polarized filter into such a angle that it filters the rainbows, you should eliminate alot of the RBE's. So just try out which rotation of a polarized filter reduces alot. This could be a solution for a lot of people

I find that a lot of heavy gamers see rainbows. Just a pet theory so far. I find a lot of agreement with it. Nongamers so far have no idea what I am talking about. They seem to be immune to the effect. [/B]

Well, the heavy gamer theory makes sense as it is quite obvious that by darting your eyes around the screen you can more easily see rainbows. A heavy gamer may have "learned" to dart their eyes around the screen because they want to focus on everything instead of looking mainly at the center only.


These persons are driven mad (ok a bit exaggerated) by certain flashing lights or moving objects. E.g.: I can't read in moving car bending a little forward; 75 Hz or lower monitors drive me mad. I get a headache or even nausea.

I fit your "category 4" (I saw so many rainbows and got headaches from the one 2x DLP projector I bought that I returned it).

I don't think I'm driven mad by certain flashing lights or moving objects -- don't have a problem with strobe lights, not epileptic, etc. HOWEVER -- I can't read in a moving car (makes me nauseous), and I am VERY bothered by low refresh rate monitors (I run mine at 85 Hz with no problems but get headaches at 60 Hz, not sure about 75Hz). I can see a monitor "blinking" at low refresh rates and always tell people they should up their refresh rate. I also get sick easily (nausea) on ANY amusement park ride that spins in a circle.

I find that a lot of heavy gamers see rainbows. Just a pet theory so far. I find a lot of agreement with it. Nongamers so far have no idea what I am talking about. They seem to be immune to the effect.

Hardcore gamer-no rainbows here.

Must this be a religious war of DLP vs. LCD, or should we better try to gather personal experiences and opinions?

I extensively have tested all kind of PJs: from cheap LCDs and single-chip 2/4/5x DLPs up to 3-chip DLPs and DILAs costing more than my car (I like good cars :-). Often, despite my efforts I couldn't see any rainbows above 4x speeds, while my wife could see them w/o even looking for them. So what, some people are sensitive, isn't it?

Rainbows are not an issue; at most rainbows are a minor, perhaps educated, nuissance. The real problem with single-chip DLPs lies in their inherently compromised principle: 3-rd order aproximation of reality.

Assumption: Our visual 'reality' is continously moving and colored, instead of discreetly in frames and bits per color channel, respectively.

1st order aproximation: additive RGB color composition. Acceptable compromise, as well as the subtractive process. Practical alternatives: none.

2nd order aprox.: moving pictures in 24-30 fps, based on studies done more than a century ago. In reality, good gamers and hi-end closed loop animation applications can make the difference between 24, 30, 50 and 60 fps (all progressive, in stead of interlaced). Practical alternatives: increase the fps as required by app.

3rd order aprox.: field sequential color composition, as in the single-chip DLP engines. This builds on the previous two orders of aproximation --or should I say, tricks?-- but apparently it extrapolates one too many. Net result is excessive load on the visual cortex, because now the brain has to perform a lot more work for colored fields. Hardly a speculation, since some pros have noticed fatigue during long sessions with single-chip DLPs. How much cortex overload only a scientific study may quantify, if TI will kindly sponsor such research :-). Practical alternatives: 3-chip DLPs and GLVs (http://www.siliconlight.com), LCOS and LCD.

Rainbows or fatigue, the concept is crooked to save 2 optical paths, a few lenses, prisms and chips. Instead of compromises that insult the human sensorial and processing capabilities, better invest more in the alternatives, which will eventually bring the cost down for technologies better fit to survive.
I hope that the field sequential color composition will be soon obsoleted and relegated to special applications, too size/cost sensitive for anything better.

Mitch-

Interesting Mitch,

Makes me think we are (after all) trying to make a silk purse out of a sow's ear. Perhaps in reality the manufacturers are trying to fill a low end HT market with a inexpensive product that really saw it's primary use to be that of corporate demonstrations, pie charts and more static type visuals.

I would think the problems caused by the current DLPs would not be as obvious in that business world where Power Point type and slide presentations are the norm.

Necessity is oft the mother of innovation. I need to reduce the rainbow effect. So I'm trying to be inventive. Like I said earlier .. it's all really an optical dillusion. :cool:

not true. we use projectors for presentations and I can definitely tell when it is a DLP because the headaches start in 10-15 minutes

Thanks for that info Tony, I guess the DLP technology isn't a great thing in either case for those of us who see the rainbows. Meanwhile I guess it's either get a faster wheel version or use some kind of bandaid like lens filters or what-ever.

Too bad .. cuz that little 900 dollar X1 PJ sure does have a nice picture. I'm committed to it ($$ restriction) so I'll keep testing.

Rich,

You won't be disappointed with the filters. I saw it vs a Ht1000 and a sharp 10k at the shootout and if anything, its a great value pj for under 1k.

Victor

I am just getting into this subject and I saw two dozens of beamers on display at a specialized dealer (mediastar.de) last week. My parents live near it so my mother took a look, too.
Knowing that I am rather sensitive against dynamic effects (85 Hz is not completely stable for me on my 20" CRT, directly compared to my static TFT display), I flatly told the salesman, "show me the rainbow effect" =). I don't know which device he was then showing us but it was indeed terrible and immediately noticeable even with little eye movement. My mother said this was unacceptable to her for continued viewing.
Then we checked out some high end model with a 6x (300 Hz) colorwheel, and the effect was still visible when I moved my eyes rapidly. The salesman was rather astounded of this and said it was impossible to see for him as well as everyone (? hard to believe) he had shown it previously. I must say it was not that obvious and fairly good when keeping the eyes at about the same spot, but it was by no means invisible. The pattern of the fields with the rainbows looked like several vertical, slightly diagonal, distorted stripes. On the slower device, they had the shape of a boomerang with the bow bending to the right if I remember correctly.
So that's my encounter with DLP ;). Well, I think the solution with the color wheel is a compromise anyway and will disappear when the technology gets more mature. Or they will speed it up to such a high speed that the effect becomes negligible for everyone.
BTW, I did not find the picture that much superior compared to the LCDs. The black level might have been higher, but dim parts of the picture were often too dark. Also, wrong colors were all over the place, each device had its own, completely unique color temperature and only one can be the right one. Frankly said, it looked liked there was no justification to spend a single additional buck for anything above the Z2/AE500 if it's not a CRT beamer. The DLPs did look a bit more CRT/Film-like, but the different color characteristics made it appear that the colors are looking more pleasing subjectively, but still have huge deviations from the correct ones. Made me wonder if the alleged "more natural colors" are backed by objective data.

http://leif.cx/rainbow-test-small.gif (http://leif.cx/rainbow-test.gif)

Click on the image for full res version, but the low res version will work fine for the effect too.

Displaying this static image on a DLP is probably the surest way to see rainbows.

I came up with this idea yesterday, after visiting a bar that had this weird light-bar thing on the wall.

It was a row of red LEDs - 64 leds in a single row (a 1x64 pixel display - mounted vertically).

These LEDs were flickering in a vague pattern.. And I realized that whenever I shifted by eyes across it, an image would POP OUT at me.

Object1___________|Vertical Display|___________Object2

Any time I shifted my eyes between Object 1 and Object 2 (without moving my head), I'd see it.

This was a pretty major coincidence for me, as I realized this is the EXACT SAME REASON / CIRCUMSTANCE rainbows appear. So I tried it, and.. Oh my god.

The two people I showed this image to on my Mitsubishi XD300U were blissfully unaware of rainbows before. After viewing this image for a few seconds, they absolutely understood why I'm selling that DLP projector.

I'm serious, guys. If you like your DLP projector, and is blissfully unaware of rainbows, you should probably not view the image above on a DLP :).

Comments, anyone?

///Leif

Simply put, When I first got my projector they drove me nuts for the first week. Now, a few months later, I don't see them at all and have to actually try to spot them while watching movies. Nobody who has watched my system has made any mention of the effect to me either. I swear the longer I have my DLP, the less I see the rainbows.

I'm sure I've just gotten used to them, but that's ok with me.

Bottom line: rainbows have become a non issue for me at least.
projector = pb6200


cheers
paulblack

http://hyperphysics.phy-astr.gsu.edu/hbase/vision/colcon.html#c1

Check this interesting page out concerning our RGB cones. The color section of that website is very informative.

(1) After reading about how our cones are divided into R, G, and B cone cells, the concept of the color wheel is not as deceptive/unnatural to our senses as I previously thought. The color wheel wheel esentially breaks down the RGB components and spreads them across the time dimension...however, "motion pictures" are spread across the time dimension too AND our eyes naturally divide colors into RGB components anyway. So with a color wheel, our eyes actually have to do LESS work to decipher colors than without color wheels since the colors will already be pre-divided:)!!

(2) Many of us have seen the science museum display effect of a half black and half white disc and when HAND spun (not even that fast), what do you get...the rainbow effect!! This means that the rainbow effect can occur even without an RBG color wheel. It occurs whenever us humans perceive speedily changing images under the right conditions (even with pure sunlight as the source). http://www.exploratorium.edu/exhibit_services/exhibits/b/benhams_disc.html and http://www.scitech.org.au/dazzle/download/Daz_BenhamTop.pdf

With (1) and (2) stated, it makes me think (and as many others suppose) that there will be a REASONABLE color-wheel speed in which the RBE will disappear for 99.99% of the population. But because of (2) RBE will be a reality even with LCDs/LCOS projectors.

I've seen it in many different circumstances, including watching rear projection CRT TV's and also in rooms with certain lighting, perhaps flourescent lights with bad ballasts? What I saw while watching the rear projection CRT TV was only interesting in that I saw it and it looked "like" a rainbow from DLP. Big difference was zero headaches and/or eyestrain with the RPTV vs wht I experience with DLP projectors.

I would be curious to know what are the home theatre projectors which have the least tendency to cause rainbows for sensitive viewers. Perhaps I'll scan this thread again. Anybody have a clue what the best projectors are for having minimal or no rainbows?

What dlp might need is a screen that "glows" for a split second, sort of like the glow that you see on a normal crt after you turn it off.

That way, the color-wheel colors on the screen will actuall blend. The perfect "glow time" would probably be about 1/30 of a second or whatever the frame rate of movies/TV signals are or less. In an electrical analogy, it is like a low pass filter designed to smooth out voltage spikes.

A physical analogy would be like the shocks in your car that help smooth out the ride. Right now we are watching dlp without any "shocks"...what is the projector manufacturers' solution? They sell us a faster car so we can drive faster still without shocks!! (i.e. color-wheel spins faster)

"The color wheel wheel essentially breaks down the RGB components and spreads them across the time dimension...however, "motion pictures" are spread across the time dimension too AND our eyes naturally divide colors into RGB components anyway. "

The issue is in *how* "our eyes naturally divide colors into RGB components"; this algorithm is not known yet, but it doesn't seem time multiplexed (may be space-muxed?). The color-sensitive retina in general, and our fovea in particular, is the results of millions of evolutionary years across many species. Projection may arguably be the oldest and most natural image rendition 'technology' ever known to man (e.g., begins with shadows cast on cave walls :-). Yet I doubt the Neanderthalian retina ever expected the R,G,B-flashed image of an attacking saber-tooth ...

"So with a color wheel, our eyes actually have to do LESS work to decipher colors than without color wheels since the colors will already be pre-divided!!"

This is an interesting hypothesis, the anti-thesis of anecdotal headaches; also demotivational for 3-chip DLP PJs. Perhaps TI should pursue this venue and fund some research proving that single-chip DLPs should replace both, 3-chip DLP and GLV technologies (www.siliconlight.com). :-)

"RBE will be a reality even with LCDs/LCOS projectors."

Not many RBE complains or observations so far from LDC/LCOS. To conclude, I find this post educational and entertaining; its conclusions, however, need some form of validation - factual, anecdotal, or scientific.

Mitch-

biomed_eng2000:
Your point 1 doesn't make any sense. Of course we have receptors for the primary colors red, green and blue, that's where the idea to use the additive RGB color composition in display devices comes from - did you think this is matching by chance!?
The concept of the color wheel is indeed quite unnatural, because the color components of movies as well as of vision in the real world are NOT spread over the time dimension; red, green and blue are displayed at the same time.
An ultrafast color wheel might make the effect invisible but this has nothing to do with some weird "pre-divided colors" or whatever you are trying to say there. The RGB composition is an approximation of nature: all 3 colors emitted from a small spot instead of an inifintely small one, and this works because it looks like one spot, given enough distance.
The color wheel is a technical trick that will hopefully disappear once the technology has matured far enough.

I am getting a headache just thinking about this...lol...

Originally posted by cpc
I am getting a headache just thinking about this...lol...

Er .. makes one wonder .. like the proverbial "tree falling in the forest" ... Do rainbows exist if no one is there to see them?

As I said all along .. It's an optical dillusion .. or a "pigment" of your imagination.

Arggghhh ... I'm sorry I said that. :cool:

Originally posted by biomed_eng_2000


(2) Many of us have seen the science museum display effect of a half black and half white disc and when HAND spun (not even that fast), what do you get...the rainbow effect!! This means that the rainbow effect can occur even without an RBG color wheel. It occurs whenever us humans perceive speedily changing images under the right conditions (even with pure sunlight as the source). http://www.exploratorium.edu/exhibit_services/exhibits/b/benhams_disc.html and http://www.scitech.org.au/dazzle/download/Daz_BenhamTop.pdf



What do you guys think of (2)?...where RBE occurs even with PURE sunlight?

Originally posted by audiophobe
biomed_eng2000:
Your point 1 doesn't make any sense. Of course we have receptors for the primary colors red, green and blue, that's where the idea to use the additive RGB color composition in display devices comes from - did you think this is matching by chance!?
The concept of the color wheel is indeed quite unnatural, because the color components of movies as well as of vision in the real world are NOT spread over the time dimension; red, green and blue are displayed at the same time.
An ultrafast color wheel might make the effect invisible but this has nothing to do with some weird "pre-divided colors" or whatever you are trying to say there. The RGB composition is an approximation of nature: all 3 colors emitted from a small spot instead of an inifintely small one, and this works because it looks like one spot, given enough distance.
The color wheel is a technical trick that will hopefully disappear once the technology has matured far enough.

I made point (1) because it amazes me that the color wheel effect works at all!

As a follow up:
Can all the colors be created even if we didn't use RBG but used three other specially chosen colors instead...?? (I am obvoiuosly new to the science of color)

"Er .. makes one wonder .. like the proverbial "tree falling in the forest" ... Do rainbows exist if no one is there to see them?"

Maybe they don't exist when I'm not there. The problem is they do exist while I'm there. It's no pigment.

There is also the YUV colorspace as well as CMYK, the subtractive composition for prints.
About that paper; decent video cameras are not prone to the "color tearing" effect anymore since decades.. this would not appear in any modern production and is not an issue with film cams at all.
Rainbow effects in nature can be caused by refraction through diaphanous material, like water.. I don't think that effect has anything to with temporal spread. DLP RBE is and remains unnatural =).

An interesting note about the RGB color rendition. Sony has released a new still digital camera with a 4th color filter .. they call it RGBE, the E standing for Emerald I think. The claim is that it allows the camera to see and define colors closer to what the human eye perceives.

I wonder if/when this technology might be added to the current DLP color wheel thing.

Read about it here:

http://www.dpreview.com/news/0307/03071601sonyrgbeccd.asp

biomed_eng_2000, On your point (2):
I'm no expert, but I semi-believe that RBE is due to several different factors that can occur alone or in combination: sequential color, changes in contrast, and brightness intensity. Also, a person's suseptibility is a major element which is indicated by known factors like saccadic eye movement, fatigue, eye health and brain function, as well unknown factors.
Some people have been able to eliminate RBE by diminishing one of the factors, like turning on a lamp to diminish brightness.
As for the pure sunlight, that is the lightsource for natural rainbows. I don't see why anyone would assume that water particles in the air are the only possible way of creating a rainbow with sunlight.

As to your follow up: Again, I'm no expert. But I believe the only colors the eye actually sees are red, green and blue. So I'm not sure if you could use other colors to create a rainbow. But maybe.l

http://www.scitech.org.au/dazzle/download/Daz_BenhamTop.pdf

Are there any comments on Benham's effect, similar to RBE but done with a black and white spinning top instead of a dlp color wheel. Perhaps what people are attributing to RBE is actually the Benham effect.

On similar note, can someone lead me to an article or experiment in which double blind tests of LCD/CRT/3DLP vs single PLD have been done in relation to people correctly identifying RBE?

For example, it would be interesting to see if people incorrectly say a projector is exhibiting RBE when they are actually viewing an LCD.

Hopefully this link has not already been referenced...this answers my question as to how fast a dlp color wheel needs to spin in order to eliminate RBE (at least this is what RCA's research with the military has indicated)

http://www.extremetech.com/article2/0,3973,1153392,00.asp

biomed_eng_2000,

VERY interesting page. Love the mpeg demo. Works to show that rbe pretty good. Thanks ..

Haha, the wheel speed necessary to eliminate RBE would be around 25000 RPM. I guess this mechanical problem won't allow single-chip devices without RBE for a long time.
And there don't need to be any blind tests done, the effect is easily visible and I doubt it is only for a small percentage of people. That statement rather looks like marketing nonsense to me. Anyone not seeing RBE on a 2x device must have really "slow eyes", the effect is very obvious.

At higher wheel speeds such as 4x and 5x, I just wanted to make sure RBE was not a "video snob" issue.

i.e. Like some audiophiles say they can hear differences between a high end $20,000 100 watt solidstate amplifier and a $600 100 watt solidstate amplifier. (Double blind test have shown that there is no humanly audible difference under those test parameters).

Originally posted by biomed_eng_2000
At higher wheel speeds such as 4x and 5x, I just wanted to make sure RBE was not a "video snob" issue.

i.e. Like some audiophiles say they can hear differences between a high end $20,000 100 watt solidstate amplifier and a $600 100 watt solidstate amplifier. (Double blind test have shown that there is no humanly audible difference under those test parameters).

Did any of you guys look at the Mpeg sample of RBE on that web site that biomed- sent?

I think we are missing something. The fact is that the RBE was RECORDED by a camcorder. By shaking the camcorder the resultant video clearly showed an exaggerated form of RBE. Note this wasn't a human eye seeing this but a camera capturing it.

IMHO this seems to be a very mechanical thing. Why some are affected more than others is now even more puzzling after viewing that clip. The effect can easily be duplicated by a shaken camcorder.

BTW, I am one of those who CAN see the RBE. I've only had my X1 PJ for a month now, and am still in the construction phase of my HT, but I have tried various experiments. I've found the following that may or may not be of interest.

1. Right out of the box I deliberately TRIED to see them. And I DID. Not bad, not a lot, only a few times in certain scenes during a long movie. It was more of an aggravation or distraction than any other kind of physical problem.

2. I have some classic B/W movies, (Citizen Kane, etc) I thought watching those should be pretty bad. BUT try as I might I could NOT see any RBE on those B/W movies.

3. I have actually LEARNED to ignore them. I now can sort of turn on or off the effect at will. Don't know how ... I just start a movie and clear my mind and lean back in the chair, concentrate on the "whole picture" ... and no rainbows. Take the same movie and concentrate hard looking for them and I see them. VERY curious.

biomed_eng_2000:

It is obviously not a "videophile snob"-issue if someone like me, who does not even own a beamer, checks out the picture at a showroom for the first time and sees the RBE on a 6x wheel device immediately. In my first post in this thread, I have also described how it looks and how it differs from the shapes shown by a 2x device.

And about the audiophiles, well, I hate their snobism as well, that's why my nick is the opposite of 'audiophile' =). $600, btw, is not enough for an amp that sounds the same as top of the line models though.. even on pages of some anti-audiophile engineer, I read an estimate of $800 for the material alone when building a "perfectly sounding" amp. Production models usually cost several times the amount of the parts, hence such an amp can easily cost $2000 to $3000.
When ranting about audiophiles, I would talk about nonsense like $10k cables =).

I fail to see some of the points made from post #321 on. These seem highly speculative:

1. RBEs are a general issue for any imaging technology; they are not associated solely with 1DLP. Therefore, color-wheeling 1DLP is equivalent to any other PJ technology (LCD, LCOS, 3DLP, GLV).... (?!)
2. Field-sequential color wheeling (time-muxed RGB) may be in fact beneficial to the human retina and visual cortex - despite what studies and anecdotal evidence have shown so far (artifacts and headaches). Thus, 1DLP emerges as potentially the most desirable PJ technology.... (?!)

biomed_eng_2000, intelectually I enjoy your speculations wrt. colorimetrical issues, yet some immediate derivations may mislead the reader (unless you produce some form of PJ-specific proof - even proof by authority is better than none). E.g, prove RBEs *and* increased visual cortex activity (headaches) with 3DLPs or LCDs. To quote from your links "To this day no one theory can completely explain the illusion created by Benham's Top."

Until then, the single-chip DLP remains a technical compromise that fills (for the better or worse) a low-end market niche and some special applications, quasi-static displays. For HT/moving pictures this compromise is arguably inferior to anything else available today in PJ technology at the same price; whether or not acceptable, this is a personal issue. People choose to drink, smoke or abuse their cellulars irrespective of health consequences; which they often unwittingly ignore. Same with color wheeling - visible or not, RBEs are but the tip of the iceberg.

Mitch-

"Why some are affected more than others is now even more puzzling after viewing that clip."

I think it has something to with if you did drugs in the past or not. I find out those who don't see them haven't done drugs. Those that have, do. I'm a have and wala another successful sample. I guess I expanded the mind a little to much. :)

It would be interesting to see:

(1) If there is a correlation (either proportional or inverse) of severity with people's observation of 1dlp chip RBE and Benham's effect.

OR

(2) If there is a correlation with the severity of the RBE and a person's maximum eyeball speed (i.e. the maximum speed in which a person's eyeball can move from side to side.

The above tests might be able to differentiate if RBE is a "rod/cone/nerve/brain" phenomenon as would be indicated by a correlation of (1) or
merely an "eyeball muscle speed" phenomenon as would be indicated by a correlation of (2).

Since we don't have the answers to RBE, perhaps we can disect the questions into easier to answer ones.

For those of you who can not see rainbows and want to see it for yourself, try the following trick:

Turn on your DLP projector (any make or model - even 5/6X color wheels)
Get a small mirror of any kind (a lady's foo-fooey mirror will do just nicely) and stand in the middle of the image throw (basically, stand in front of your screen). Angle the mirror so it projects part of the image on another wall. Now gradually move the mirror and watch the 'bounced' part of the image as it moves. The faster you move the mirror, the more rainbow color effect you'll see. For obvious reasons you'll want to pick a light colored part of the image.

There you go - it's simple - for all of you who think it's a minor thing, imagine it happening everytime something moves quickly. Uggghh!

My son was visiting today and we did a couple more tests. He sees more rainbows than I can, and in places that I can't see them at all. What was most interesting was that I have a "hot spot" on my screen (not finished yet) and he says the rainbow effect is most prominent there.

After the tests he put on his prescription sun glasses and we enjoyed a movie .. sans rainbows. Even the ones in the hot spot disappeared when he watched with his shades. As mentioned earlier, his sun glasses tint is very minimal .. so it didn't really dim the movie very much.

I wonder if a neutral density filter at the PJ would have the same or similar effect on your son's viewing?

Back a ways in this thread we discussed filters. That plus a polarizing filter are a couple things I'm going to try on the PJ (as soon as the local camera swap fest comes to town) They usually have a bunch of vendors selling used filters. Otherwise to get the correct size (large) filter at a new price would be more than I'd like to spend just to test it.

In #344, Fido_one proposes a simple test. Whereas I haven't tried it yet myself, this should work because moving the mirror amplifies the moving speed of the reflected image. From basic optics, 1st a reflection doubles the angular speed; 2nd, it amplifies this movement proportional with the distance. Try this with 1DLP, 3DLP, LCD, LCOS.

Mitch-

I dunno. Sometimes I think you guys don't really read all the posts. (yes in some cases it can be daunting) Back a ways in this thread I posted a link to a web site that also had an actual sample of the rainbow effect ON VIDEO. You don't need to be able to see rainbows, nor do any special tests. Just play the video.

The guy had a white circle being projected by his DLP Projector. While the projector was running, he used his camcorder to record the image off the screen. While recording he shook the camcorder. The result is that the camcorder recorded the RBE. Because of the heavy amount of shaking the effect is even more dramatic.

Here is an attachment of a still frame taken from the 5 minute clip. The important thing to realize here is that this RBE was NOT being seen by a human. It was recorded by the camcorder. I won't go into what that means or doesn't mean, but I find it interesting that the phenomenon is more "mechanical" and can be duplicated or perceived by hardware .. not the human eye. It doesn't take a rocket scientist to see that the effect can be keenly observed in a controlled environment .. Ie amount of movement, direction, type of video being projected, yadda yadda. This attached snapshot was taken from the video after examining the 29.97 frames per second video, frame by frame and saving one frame as a *.jpg.

Hey Rich,
FWIW RE hot spots - I was watching the beginning of a B/W movie on my old 53" Sony RPTV last night (20,000,000 Miles To Earth). I have a hot spot in the center of my Sony. When a boy in a checkered shirt passed into the hot spot, I saw colors.

I think that camcorder was delusional and had an anti TI agenda, since i don't see rainbows they don't exist


signed: DMD proponent


:)

Thank you, Rich, for the snapshot in #349. It's additional relevant evidence that visual effects of RBE type can be recorded; therefore one can conjecture that RBEs are more than sensorial artifacts, visible only to selected individuals. RBEs are factual and recordable, i.e. an objective phenomenom.

OTOH, the mirror proposal in post #344 is a simple subjective test, useful to those who whish to compare multiple 1DLP PJs, w/o having multiple hours (required!) to spend with each unit. Valuable, though subjective, this mirror is a tool I'd use for pre-purchasing decision.

Next, we should carefully distinguish between the color-wheeling's (more or less) visible RBEs and the seemingly associated subjective overload of the visual cortex, aka headaches. According to anecdotal evidence, cortex overload is possible even in the absence of any visible --to a given person-- RBEs. While this issue needs more study, i support Mr. Powell's position:

"And even for some who cannot see the rainbows, the sequential refreshing can produce eyestrain, visual fatigue and headaches." http://www.projectorcentral.com/optoma_h30.htm

I recommend caution and multiple test sessions to all those --including family and friends-- who consider 1DLP projection technology of *any* speed for HT applications.
Mitch-

I believe that the color of the screen, and maybe even the type of screen has alot to do with seeing rainbows. My friend and I have the same projector , the x1. At his house, with just a tan wall for a screen, I can see no rainbows. At my house, however, with a baehr ultra white painted screen, the rainbows are visible to me.

Mainly on white , fast moving objects, inside a dark area. Also, on the credits of most movies where the white names scroll down a black screen. It, like others have said, becomes evident when I look away from a white object to another area real fast. There is a very fast flash of color bars.

I have noticed that on one game that had alot of rainbows I did get sick. I got so quesy I had to stop playing. This, in fairness to the discussion, could also have been becasue I was playing a long time, and just getting used to the big screen size. There was alot of rainbows in that game though.

Noone else viewing a movie at my house has mentioned the rainbows . Had I not knows what to look for I might not have quantified my problems. I would still see them, but probably not have viewed them as a flaw so much.

All in all.. my infocus x1 provides a wonderfull picture so I am keeping it. If the new 4805 was out, I might give it a shot.

I sure am glad I bought my SONY HS10 LCD projector. I would hate to have to provide sunglasses to all my family when they watch a movie!

Originally posted by actonweber
I sure am glad I bought my SONY HS10 LCD projector. I would hate to have to provide sunglasses to all my family when they watch a movie!

Sunglasses .. ;) My example was for testing. I've had about a dozen people view my setup. Only one (besides me) saw them and that was my son. (Who eliminated them with the sunglasses) After I finish my tests, and determine the correct "prescription", I'll just get a filter for the lens. No sunglasses needed. <grin>

But I must say, even though my X1 is RBE-impaired, the color, contrast and brightness are outstanding. I went though special pains to keep the room extremely dark, and now find I can run the PJ in just a dimly lit room with no problem at all.

I think when I finish the screen painting and change it from a very glossy pure white to a Gray flat finish the RBE will be lessened a lot.

FWIW, I've been watching normal network TV (both 4:3 and wide-screen) for about a week (a couple hours a night) and at this point the RBE has become a non-issue.

Hello. Just chiming in with some RBE thoughts...

I had an NEC LT240 and an NEC HT1000. I could see rainbows on both of them. I did have queasiness issues with both, although the feelings lessened as I got used to them. I returned the HT1000, and sold the LT240. Strangely, the LT240 had the sharper picture - perhaps the HT1000 was faulty, thus exacerbating the RBE.

I also demoed a Sharp DT-200 (aka long throw Sharp Z90). Rainbows were rare, even while watching the battle scenes in The Two Towers. After seeing rainbows on the DLPs, I began to see similar artifacts on my 40" CRT RPTV, in the same scenes. A 5x color wheel pj just might make RBEs a non-issue to me (only occasional flashes, I hope), although I would like to demo the new HD2 or HD2+ projectors with high lumens first before plunking down $$$ on something like the excellently valued Benq PE8700.

I like the idea of eyeball speed being a factor. Saccade I think it is called?

Hypothesis: The more tired your eyes, the slower the rate of eyeball travel when it moves around the screen. When the eyeball moves slowly, your brain will sample more frequently WHILE the eye is moving, and the angular speed of the eyeball will cause one to see the color separate. When the eye moves from point A to point B, the color wheel may be displaying green - thus, your brain perceives green only. From point B to C, the wheel may be at the red segment, thus you will see a separate red image. However, because your eye has moved, the image will not be lined up exactly.

BTW Rich, what kind of sunglasses does your son use? Polarized? What kind of tint? What brand and model?

I played with a circular polarizer on the NEC LT240 and the NEC HT1000. It didn't make any difference with rainbows. But then it could be the reflectivity of my walls negating the effect of the polarizer. Walls with a bit of texture (ie. painted with eggshell-like paint) might make rainbows worse, for example.

Interesting comments. Thanks .. As for my son's sunglasses, they are prescription. Not a name brand. But they are sort of a light grey, and are polarized.

I've been enjoying the HT so much that all work has come to a stand still. ;) So I haven't painted the screen yet. I hardly notice the RBE at all now.

I've also found that plain old greyish tinted polarized clip on sunglasses work very well for me too. I normally wear glasses.

But interestingly enough, I also find that if I watch the movies WITHOUT my glasses, the RBE is just about gone. My eyesight isn't so bad as to need the glasses when watching the big screen. More for reading and driving (so I can see the street signs BEFORE I pass them) Harrrrr.

Another note .. I thought I'd really have a problem with my old movie B/W shows. I have a modest collection of full screen old classics (4:3) in black and white. (Citizen Kane, To Kill a Mocking Bird, some old Bogart movies etc.) So far they show RBE to me the least. If at all.

Thanks for the reply Rich! This thread isn't quite dead yet! ;)

I wonder how different polarized glasses are from regular circular polarizers. You have to rotate the lens with the circular lens to get the effect you want. I wonder what angle polarized sunglasses use?

The light drop from a circular polarizer is roughly the same as an ND4 filter (or is it ND2?) I think. That's quite a huge light drop. Do your sunglasses drop the apparent brightness by a similar amount? You said there was hardly any loss, but I'm thinking it is your irises opening up to let in more light...which is very interesting in itself with regard to RBEs. :)

Dang, I really have to find an HD2 DLP projector around town here...I'm itching to try Casablanca, Dark City, and Matrix Reloaded on them.

Well just to add a note or two, (which I may have mentioned before). There's a "hot spot" on my screen and it seems like if I am going to see any RBE, that's where it'll show most often. My screen is home made and is recessed about a foot into a closet that does a really fantastic job keeping the actual screen area dark. I haven't even painted the inside black yet either. The "shadow box" effect was really quite stunning.

I devised an interesting variable masking setup (which works really great) but believe it or not, even when I don't use the masks, the light spill over when watching 16:9 frame on a 4:3 screen is very hard to see. Of course the black felt mask makes it disappear completely.

My sun glasses are not very dark. A very light grey actually. The combination of the "black hole" that the screen is in, coupled with the slight dimming from my sun glasses really makes the whole thing just about as good as it gets. Now that it's finally gotten warm enough, I think I'll bring the screen out to the garage and paint it. The only issue left for me now is that hot spot. People who have watched movies cannot believe the screen is home made. This whole thing was done as an excerise to see just how inexpensive a half way decent HT can be built.

Just wish I had more real estate to work with. Still waiting for the local camera bazzar to come to town so I can pick up a few filters to experiment with.

Lastly, I don't notice the lowering of brightness when wearing the sun glasses. The room is very dark, and as I mentioned the screen itself is in a very dark hole. So much so that I actually had to turn DOWN the brightness, contrast and colors. Still there is plenty of "punch" in the displayed video, even with the "shades" on.

Strangely, the LT240 had the sharper picture - perhaps the HT1000 was faulty, thus exacerbating the RBE. Not strange at all. I found the 240K to be sharper than the HT1000 as well. The review at ProjectorCentral.com also noted how sharp the 240K is. (Not 100% sure if you are referring to the 240 or the 240K though)

Hmm. I can't remember the difference between the 240 and the 240K...the one I had I purchased in May of last year I think.

I was at the new Best Buy in Calgary, and checked out the Samsung DLP RPTVs. Not bad...the 61" was particularly cool, aside from the poor picture...how can they make Finding Nemo look so bad? It was even hooked up to component inputs with progressive scan...weird. But, I couldn't see any rainbows, and they were barely noticeable when I went into the TV picture menus. However, there was a lot of ambient light from the overhead lights - when will they ever place the high-end tvs in a dark room?

I was starting to feel some tension behind my eyes after a few minutes. I did not get that feeling when looking at a non-DLP TV of similar size, although that could have been a fluke. I suppose not having a DLP projector for nearly a year has untrained my brain. ;)

Unfortunately I could not find a place that can demo a Benq 8700 to me...that local dealer that sells it said they would demo it for me, but they have no light control and no showroom. D'oh!

I'm hoping to visit a home theater shop and see if I can handle the new brighter 5x HD2 projectors...if I can tolerate it for more than 30 minutes of viewing I might pull the trigger on the 8700.

Anyone experience rainbows on the BenQ PE-8700? I'm looking to buy one if rainbows aren't evident. If yes, then I will probably go with the Panasonic 500u as my alternative.

Any info would be appreciated! Thanks in advance...

Jason

At the recent Canuck Shootout 2, I don't recall anyone at all seeing any rainbows on either the + or non + 8700. However, I did read about one person who did see them even on this pj so if you are highly susceptible, the likelihood of you seeing them is greater than most. You really should demo first to be sure. They may go away though over time for you given that the color wheel speed is fairly fast. But it's an expensive gamble to take.

I also demoed the X1 and saw rainbows with in a minute of hitting play on DVD (ahh, that's what everyone's talking about)... I only used the X1 for another two hours during the next 10 days and did not see them again but two hours is not very long. My very brief exposure to rainbows was enough to make me consider other projectors. So I bought an older Epson 5500 LCD and a Sony CRT.

This is a great forum but I have to say that saying "any other threads about rainbows will be deleted" seems kinda silly. I mean if you think about it, Every single topic on these boards is discussed over and over and over again. If the mods want to limit discussion .. then why not lock all threads up right now because rainbows are no more the subject than any other topic.

The mods have to understand that this place is organic in nature. It's always growing with new members. Threads like these assume that this place is limited to the current members only... If I knew member posts about rainbows, why not treat it like any other topic and let it run it's coarse.
I don't know. It just seems silly to me tell people what they can and cannot post about. Members should feel that they can disuss all aspects of Projectors related topics..not just the ones the mods say are ok.

ou812, if you had to see as many "rainbow" threads sprout up as the Mods have you might see things differently. All the Mods agreed that this was the right choice, the past result was multiple daily rainbow threads that just resulted in two sides bitching at each other. This is why we also delete the LCD vs DLP threads when they get out of hand...

BTW, If all new members read the FAQ and Forum Posting Policy there wouldn't be a problem. ;) I'm still deleting rainbow threads that most people didn't even know existed.

Besides, now we have a great source to refer to when people have questions about rainbows.

Originally posted by Kysersose
ou812, if you had to see as many "rainbow" threads sprout up as the Mods have you might see things differently. All the Mods agreed that this was the right choice, the past result was multiple daily rainbow threads that just resulted in two sides bitching at each other. This is why we also delete the LCD vs DLP threads when they get out of hand...

............ BTW, If all new members read the FAQ and Forum Posting Policy there wouldn't be a problem. ;) Yea but who takes the time to read those?:D

Besides, now we have a great source to refer to when people have questions about rainbows. True but than again, Why not condense all the information and give each subject it's own topic and tell everyone they can only post in the relevent topics? NO NEW TOPICS! because when you think about it.. there really are no new topics.

:D I still think it's silly but.. You're the mod not me!

Yea but who takes the time to read those? Exactly my point.


True but than again, Why not condense all the information and give each subject it's own topic and tell everyone they can only post in the relevent topics? NO NEW TOPICS! because when you think about it.. there really are no new topics. Because rainbow discussion was far outweighing everything else.

I still think it's silly but.. You're the mod not me! Thanks, let's move on.

,
The lastest thing I've been hearing is that some people seem to adjust to the rainbows- meaning after a certain amount of time they no longer see them.. Anyone heard this?

Yes. I also think it has been discussed in this thread.
I myself (thanks to this forum) spent countless hours searching for rainbows when I bought my first DLP projector. After about a week I learned to just watch the movie. No more rainbows.... I "may" spot one once a week if I'm lucky.

Still no complaints from family, friends, or co-workers. My wife still thinks they don't even exist. I guess for her they never have...

Originally posted by Kysersose
... My wife still thinks they don't even exist. I guess for her they never have... Yea, that's how my wife is with the bills!:D

I saw rainbows on the Runco 710, which is supposedly based on the Benq 8700

I felt that I could get used to the rainbows, but after watching X Men 2 for about 20 minutes I started to feel sick

I was still thinking of taking a chance on the 4805, figuring I would eventually get used to the color wheel, and would have ordered from a place with a 30 day return policy

I reconsidered due to the fact that I have 2 small children and don't know how this stuff will effect them

I didn't really take guests into consideration, although I can just imagine my mother saying "your movie projector made me sick"? hee hee, but you know moms

Anyway, I ordered an HS20, it should arrive next week

Diana

ou812, if you had to see as many "rainbow" threads sprout up as the Mods have you might see things differently. All the Mods agreed that this was the right choice, the past result was multiple daily rainbow threads that just resulted in two sides bitching at each other. This is why we also delete the LCD vs DLP threads when they get out of hand...



I agree with the policy, but I must admit that I think it is taken too far some times. I can agree that any thread that is only about rainbows should be merged or deleted. But threads like http://www.avsforum.com/avs-vb/showthread.php?s=&threadid=414253

I can't understand why it was closed. It was comparing two pojectors. Yes there was some rainbow discussion in it, but it was primarily comparing two projectors.

The lastest thing I've been hearing is that some people seem to adjust to the rainbows- meaning after a certain amount of time they no longer see them.. Anyone heard this?


I think they said that they see less or that they got used to them and don't bother them as much

Yea, that's how my wife is with the bills!

lol

Unfortunately, I can see rainbows on the X1 and the faster colorwheel ScreenPlay 5700 when it is pitch dark. However, with proper ambient lighting, the rainbows disappear or are less apparent. I suggest that people play around with ambient lighting before dismissing all DLP projectors on the basis of rainbows.

Yes, I believe they do go away for some people. I bought an X1 back in Oct. and was highly supceptiable to seeins rainbows. Tried filters and stuff to really no avail (they did have an effect, just not enough or at signiticantly reduced PQ).

I have now watched nearly 1000 hrs of HDTV, DVD, etc. and no longer see Rainbows, this has been the case for many months.

Some notes:

I have never seen rainbows while playing Xbox games.
Having a little ambient light in the room helps reduce rainbows.
Rainbows rarely to never occur on HDTV content
I have never seen rainbows on SD material

Image size relative to head movement, ambient light are all factors that affect whether you'll see rainbows and how bad. In the media, points of brilliant white light and at points of large scence contrast will be the sources of rainbows.

I think I focused on the issue to much in the beginning and once I gave up and just watched, my problems went away and the smile on my face grew larger. I don't even think about rainbows anymore...

Do rainbows go away the further you sit back? I'm considering a 96" diag at 15 feet back...

Jason

Originally posted by DRulz
Do rainbows go away the further you sit back? I'm considering a 96" diag at 15 feet back...

Jason
I've heard a few people suggest that sitting farther back helps. Less "darting" of the eyes I suppose...

THanks Kysersose...

Well hmm.. I still can't really make up my mind. If I had the money for a $10k projector I would, but my budget really is $3750 max.

Know of any DLP projectors that have NO rainbows whatsoever in this pricerange?

I would go for something like the HT1000... even some people who have complained of rainbows on 2x colour wheels said that they don't see them on faster colour wheels like that on the HT1000.

If you can test out a DLP try and do just that...

P.S. I've never had any problems with my 240K and it's only a 2x colour wheel.

Well.. now I started to consider the Z2....

Hmm... have you noticed any rainbows whatsoever...? I would love to see some screenshots of it if any are available on the net...

Jason

Me personally, after having the x1 for a week:

Turned it on for mounting and calibration purposes. Saw a rainbow about every 5 minutes. Couldn't help it--I think it has something to do with my eyes just naturally whipping around movie screens trying to soak up detail, along with my wanting to read really fast and being a video game junkie a long time ago. My eyes just naturally dart around. Plus, once I saw one, I was kinda looking out for them.

Finally got it mounted and calibrated--and calibrated again--and tweaked. Watched 3 or 4 movies--and now I only see them when I want to see them. I've somehow managed to slow my eyes down, I think. Of course, the ND2 filter and gray screen I'm using help, but after awhile, much like fan noise and other interferences--your brain just naturally tunes things like that out after awhile. At least in my case. I don't hear the fan running unless I try to listen for it, and I don't see the rainbows unless I think about rainbows.

For me, the trick is to get absorbed into the movie I'm watching. Which isn't hard if it's a movie you own: If you own it, chances are that's for a reason ;) . if you're focusing more on the story the movie is telling and less on how the picture on your proj is playing, you're not going to notice Rainbows because you're not thinking about seeing them

That's not to say they still don't pop up every now and again. but I'm lucky to catch one or two a movie, if that. And in that case--I'm comparing it to a dirt blob on a print in the theater, or a scratch here and there. Something I can write off rather easily.

I'm curious...for those who get headaches/nausea/eyestrain when watching DLP, has it gone away? If so, how many hours of viewing did it take before it didn't bother you?

For me, I got used to it after about 50 hours (30 on an NEC LT240K, and 20 on an NEC HT1000).

Last weekend I demoed a Sharp Z12000U, and I had some eyestrain - but it wasn't that bad at all, and could easily ignore it. A few days before I watched a Samsung 61" DLP for 15 minutes at Best Buy, with full store lighting, and I noticed a bit more eyestrain than with the Sharp. So, in a way, my brain "forgot" to deal with the eyestrain, which was absent a year ago when I watched Below on my LT240K.

Originally posted by maxleung
I'm curious...for those who get headaches/nausea/eyestrain when watching DLP, has it gone away? If so, how many hours of viewing did it take before it didn't bother you?

......

For movie watching it took about 10 movies or so. I still see rainbows occasionally on bright white scenes or when credits run in some movies, but the eye strain and headaches are non existant now. I do however still get some naseau while playing many games. First person shooters seem to be the worst and I can get in about 30 minutes before I have to stop due to nausea. It is gettting better though. Need for speed underground really does not affect me that much now and when I first started playing it was rough on me. I did some research and it could also be that some people are more likely to be affected by dizziness due to eye Rapid Eye Movement. For instance some people can get on a merry go round or roller coaster with no ill effects...and some cannot. Many of those same people in the "not" category are usually severely affected by motion sickness wich is basically what I think is happening with many wayching the DLP's.

Like many people who suffer from motion sickness on the sea.... your body usually becomes use to it after a while...sometimes a long time.

Curious to know how many people suffer from this and also are easily affected by motion sickness in other areas ( back seat car rides, fast moving rides, ocean boat rides, waterbeds and so forth,.

Just a thought...

Originally posted by maxleung
I'm curious...for those who get headaches/nausea/eyestrain when watching DLP, has it gone away? If so, how many hours of viewing did it take before it didn't bother you?

......

For movie watching it took about 10 movies or so. I still see rainbows occasionally on bright white scenes or when credits run in some movies, but the eye strain and headaches are non existant now. I do however still get some naseau while playing many games. First person shooters seem to be the worst and I can get in about 30 minutes before I have to stop due to nausea. It is gettting better though. Need for speed underground really does not affect me that much now and when I first started playing it was rough on me. I did some research and it could also be that some people are more likely to be affected by dizziness due to eye Rapid Eye Movement. For instance some people can get on a merry go round or roller coaster with no ill effects...and some cannot. Many of those same people in the "not" category are usually severely affected by motion sickness wich is basically what I think is happening with many wayching the DLP's.

Like many people who suffer from motion sickness on the sea.... your body usually becomes use to it after a while...sometimes a long time.

Curious to know how many people suffer from this and also are easily affected by motion sickness in other areas ( back seat car rides, fast moving rides, ocean boat rides, waterbeds and so forth,.

Just a thought...

Spektrum,

I just noticed after not having my Xbox connected to my X1 that I am getting a bit nauseated from gaming.
It depends on how fast the motion of the game is. I never had it before though.

Riding a roller coaster might not apply. That's more of an actual "motion" and is more physical than anything else.

Same with car or plane sickness. I doubt it's the same thing. There are no "rainbows" involved.

I used to see rainbows but have never suffered from things like roller coasters, plane or car rides. Even reading while in a moving car does not bother me. (not so for other people I'm told)

The DLP RBE is easily duplicated with "non-human" techniques. As was mentioned somewhere (maybe in this thread) you can take a camcorder and point it at the screen and move the camcorder from side to side quickly while recording, when you play back the captured/recorded video the RBE effect is clearly visible.

To date, I've never heard of any camcorder suffering from nausea or headaches. <big grin here>

So the problem has something to do with certain people's eye movement and the fact that those people see them. I believe there are even people who actual don't "see" or should I say "notice" them but are still susceptible to physical effects caused by them.

Something not mentioned here are "subliminal" messages. We all know that said "hidden" messages can be incorporated into films and such by adding it a frame or two within the 30 frames being played at 30 fps. We don't "see" the message .. BUT our brain does. So I think some people can be affected by RBE without even realizing they are there.

In regard to the subliminal message thing, just out of curiosity I once did some tests. Made up something that had every 30th frame over-written with the phrase, "Rich is a GENIUS". After watching the movie for a half hour I felt really smart. :D :D :D

Just kidding .. but the Subliminal message really do work on most people. So much so that the government did something a while back to stop it. (If my memory serves me well)

The whole point is I DOUBT it has anything to do with the physical realm akin to motion sickness. When you ride on a plane or in a car, you don't see those rainbows. No matter how much you move your head or the roller coaster is bouncing around.

Further experiments that I've done seem to show some interesting contrasts. I have several black and white classic movies that I have recorded to DVD. Believe it or not, (for me anyway) the RBE is almost non-existent when viewing those B/W on my DLP. In fact most of my "home made" DVDs (captured from a cable tv feed) almost never show RBEs. They are, of course not the quality of a commercial DVD (still quite nice though) but now that I think about it, I really don't ever remember seeing RBE with them.

Tonight, for kicks .. I'll try a couple things.

1. watch a bunch of my home made DVDs.

2. Convert a commercial DVD that I know I can force myself to see RBE, to B/W and then view it.

3. Try ripping a commercial DVD and lowering the bit rate and re-burning it.

4. (and this may take some time) Re-recording a movie or segment at 60 fps. I "think" I can do this and keep the playback normal by doubling every frame, (which would make it play slower) but then also doubling the FPS which should make it playback at normal viewing rates.

Meanwhile my un-finished home theater is still unfinished. :(

I have several black and white classic movies that I have recorded to DVD. Believe it or not, (for me anyway) the RBE is almost non-existent when viewing those B/W on my DLP.

I found the same thing watching The Seven Samurai. I am susceptible to rainbows mainly with white on black - particularly on the edges of the white. I think all the shades of gray help keep things less starkly white on black.


As far as motion sickness, my wife gets motion sickness, and dizzy with 3D games given too much motion, but has no problem with the DLP. She sees less rainbows than I do.

Originally posted by Rich A
Riding a roller coaster might not apply. That's more of an actual "motion" and is more physical than anything else.

Same with car or plane sickness. I doubt it's the same thing. There are no "rainbows" involved.

I used to see rainbows but have never suffered from things like roller coasters, plane or car rides. Even reading while in a moving car does not bother me. (not so for other people I'm told)

:(

Yeah, I think I was not clear on my above post. I was seperating hte rainbow and naseau phenomenon. It is obvious what creates the rainbows, but less obvious why not everyone sees them. I think that the nasseau is associated to the eyes rapidly moving from one fixed point to the next. I do not believe that rainbows casue nasseau.

Similar rapid eye movement occurs like stated above when you are on a ride where things "whizz" past and the eyes cannot stay focussed. Likewise, when you are on a boat and your eyes are constantly moving from one point of reference to another as the horizon dips and rises can sause sickness in some.

I am not really guessing that the same people that suffer from motions sickness also are able to see rainbows, but am guessing the people who suffer from nasseau while playing games on or watching large screen DLP's also suffer from other types of eye movement and motion sicknes as they are all related.

Who knows. just a theory and I was curious to see how many people are affected by both of these .

When I was young I used to experience a lot of motion sickness (nausea) while riding in cars or trying to read in a car. I also got sick at DisneyWorld in the Canadian pavilion with the 360 degree movie screen. You walk into the theater - there are no seats - and you hold onto the handrail and look all around you. Ugh, the horsebuggy scenes always made me sick. Oh and the flyby around the rocky mountains with a 360 view - there go my cookies!

When I watch DLP, I feel a certain tightness behind the eyes - the familiar eyestrain. The sensation is akin to watching a computer monitor with fast-decay phosphors (flicker is much more obvious) set at 60 hz under bright flourescent lighting. Even better: watching an interlaced computer display - anyone remember using the Amiga computer at 640x480 interlaced NTSC? Or even worse: 640x525 interlaced PAL! :D

I expect the eyestrain to go away when I "retrain" myself to watch DLP again...I had no troubles a year ago when I had a couple of DLP projectors after a few dozen hours of watching.

Some questions:

On a 5x (six segment) color wheel DLP, the images are updated 300 times a second right? Or rather, each color is updated at that rate. A full image frame with RGB components should then be updated at 100Hz. Or is it really 60 hz, where it takes 2.5 passes through all 6 segments to get a complete 24 bit color image?

Also, what is the duty cycle of the 5x DLP projectors? That is, how long are the mirrors turned on and how long are they turned off if projecting a 100 IRE field? I'd suspect that the less time they are on, the more apparent the flicker would be, even subconsciously. CRTs have a phosphor decay time that reduces apparent flicker, but DLP does not...when a mirror is off so is the light! Perhaps this DLP flicker is the cause of nausea and eyestrain in some people, which is not apparent on CRTs with long phosphor decay times (no flicker if the decay is long enough).

I'm guessing that flashes of light at 300Hz can be noticed by people if, within that 1/300th of a second, the light is only on for, say, 1/5 of that (1/1500th of a second) - aka 20% duty cycle. If DLP could do 100% duty cycle, then I'd bet that incidences eyestrain/nausea would be drastically reduced.

Ok that's enough of my rambling. :)

Originally posted by Spektrum
Yeah, I think I was not clear on my above post. I was seperating hte rainbow and naseau phenomenon. It is obvious what creates the rainbows, but less obvious why not everyone sees them. I think that the nasseau is associated to the eyes rapidly moving from one fixed point to the next. I do not believe that rainbows casue nasseau.

Similar rapid eye movement occurs like stated above when you are on a ride where things "whizz" past and the eyes cannot stay focussed. Likewise, when you are on a boat and your eyes are constantly moving from one point of reference to another as the horizon dips and rises can sause sickness in some.

I am not really guessing that the same people that suffer from motions sickness also are able to see rainbows, but am guessing the people who suffer from nasseau while playing games on or watching large screen DLP's also suffer from other types of eye movement and motion sicknes as they are all related.

Who knows. just a theory and I was curious to see how many people are affected by both of these .

Ah I understand. And on second thought have to agree with you. Thanks for the explanation.

Originally posted by maxleung
When I was young I used to experience a lot of motion sickness (nausea) while riding in cars or trying to read in a car. I also got sick at DisneyWorld in the Canadian pavilion with the 360 degree movie screen. You walk into the theater - there are no seats - and you hold onto the handrail and look all around you. Ugh, the horsebuggy scenes always made me sick. Oh and the flyby around the rocky mountains with a 360 view - there go my cookies!

When I watch DLP, I feel a certain tightness behind the eyes - the familiar eyestrain. The sensation is akin to watching a computer monitor with fast-decay phosphors (flicker is much more obvious) set at 60 hz under bright flourescent lighting. Even better: watching an interlaced computer display - anyone remember using the Amiga computer at 640x480 interlaced NTSC? Or even worse: 640x525 interlaced PAL! :D

I expect the eyestrain to go away when I "retrain" myself to watch DLP again...I had no troubles a year ago when I had a couple of DLP projectors after a few dozen hours of watching.

Some questions:

On a 5x (six segment) color wheel DLP, the images are updated 300 times a second right? Or rather, each color is updated at that rate. A full image frame with RGB components should then be updated at 100Hz. Or is it really 60 hz, where it takes 2.5 passes through all 6 segments to get a complete 24 bit color image?

Also, what is the duty cycle of the 5x DLP projectors? That is, how long are the mirrors turned on and how long are they turned off if projecting a 100 IRE field? I'd suspect that the less time they are on, the more apparent the flicker would be, even subconsciously. CRTs have a phosphor decay time that reduces apparent flicker, but DLP does not...when a mirror is off so is the light! Perhaps this DLP flicker is the cause of nausea and eyestrain in some people, which is not apparent on CRTs with long phosphor decay times (no flicker if the decay is long enough).

I'm guessing that flashes of light at 300Hz can be noticed by people if, within that 1/300th of a second, the light is only on for, say, 1/5 of that (1/1500th of a second) - aka 20% duty cycle. If DLP could do 100% duty cycle, then I'd bet that incidences eyestrain/nausea would be drastically reduced.

Ok that's enough of my rambling. :)

Good stuff. Where were you guys 5 kazillion posts ago? :p Uh .. maybe some of this was already mentioned? Naw I doubt it .. I'd remember. But I'll be darned if I'm going back to the beginning of this thread and read them all just to check. haaarrrrrrrr.

Hmmm, good point Rich! I should reread all the posts in this thread again! Oh...check out this thread:

http://www.avsforum.com/avs-vb/showthread.php?s=&threadid=416641

In it is an interesting explanation of "fusion" vision by eyedoc...it might be responsible for nausea/eyestrain in some people when watching DLP:

http://www.avsforum.com/avs-vb/showthread.php?postid=3992308#post3992308

ok don't shoot me I didn't read all 20 pages. What exactly is a "rainbow" I was looking at projectors and came across mention of it here.

A rainbow is a flash of red, blue and green colors that will appear lightningly quick to some people who are sensitive to this phenomenon. It is native to DLP projectors only and is due to our visual perception being faster than the speed of the color wheel spinning in the pj which determines the colors that we see on screen. Projectors with faster spinning color wheels help to alleviate this problem and for many, eliminate it altogether. It doesn't matter how fast the wheel spins to a very unfortunate few though.
Many do not see rainbows and some others who do are not bothered by them. Still others not only see these but also experience headaches and therefore to some, DLP is at this time unwatchable a technology to them.
These rainbows tend to be quite obvious when viewing black and white material or white credits on a black background. In other words, scenes where there may be a level of high contrast involving absolute whites and blacks. Many claim to be able to replicate this phenomenon unnaturally by shaking one's head rapidly from side to side or wildly waving their hands in front of their eyes.
The good news is that a lot of people have reported to have gotten used to these rainbows over a period of time and that they have lessened significantly numerically and in overall impact.
So chances are, if you try a DLP projector and see rainbows, over time you may be one of the fortunates who realize that they don't see them anymore or see them so infrequently that it is a non-issue.
They may not show as often on a gray screen as opposed to for instance, a High Power one. For some, rainbows are exacerbated on brighter screens.
It is important to train your eyes to view or take in the entire screen at once, rather than darting your eyes back and forth from side to side or up and down. This eye movement can create instant rainbows on demand and so it's vital to keep your screen size to a proper dimension related to your room size and viewing distance. Too large a screen will force you to look around a lot. A perfect size will allow you to relax and just look at the screen, absorbing the entire image naturally and comfortably.
Hope this has helped W0ss.
It's kind of ironic that you would ask this question in a thread that's all about rainbows. It would be a good idea in the future though to try out the search function if you don't feel like reading a lot of pages in a particular thread. You will find it to be an invaluable tool for answering questions such as this. Then, after doing this and you still haven't found what you're looking for, you can tap the minds of your new friends here who will be more than happy to help.
Good luck!

Wayne

to understand rainbow you must understand how a 1 chip DLP works. It does sequentially a red picture, a green pictyure and then a blue picture. In the most part your eyes/ brain will see these three pictures and put them together as one picture. for insteance if there is a spot that is full read/green/blue you will see white.

now what are rainbows? well simply put, sometimes in some spots of an image you will see some of each of the components (i.e. flashes of colours)


when do they happen? in high contrast scenes (i.e. black and white movies are good for this), or (artificially) if you move your eyes a lot

Which means that RBE are essential 'afterimages': don't move your eyes and you don't see them, regardless of image content, drop brightness and you don't see them any more, or at least much less often...

I think that brightness is the single most important factor for rainbows and one of the reasons they tend to occur less often is that your PJs bulb looses brightness over time... Sure colorwheel speed is important but I think that brightness is of almost the same importance, otherwise it is hardly understandable that by using ND2 filters you can reduce rainbows for 2x PJ significantly.

Peter

one of the reasons they tend to occur less often is that your PJs bulb looses brightness over time

inteesting theory

I am pretty sure that this in one of the key factors, together with self -conditionend avoidance of eye movements...

I've had my Benq 8700 for over a month now. Right away I noticed that eyestrain was hardly evident for the first several hours, and then completely disappeared after that. Not even excessive dry eye - well, at least when compared to staring at a computer monitor with fluorescent lighting all day, anyways. :)

Because I am projecting a mere 65" diagonal image, it is very bright. Probably in the 40 ftL range. I see rainbows frequently in high contrast scenes, but they are not bothersome at all. In fact, I have to concentrate a little to consciously "see" them.

Just for kicks, I turned on my 4 year-old calibrated CRT RPTV, and I noticed the infamous CRT "rainbow" effect - where the green phosphors decay much more slower than the red and blue ones (red being slower than blue) - I see yellow after images that last even longer than a rainbow from my 5x color wheel Benq. Isn't that hilarious? :D

Originally posted by AnthonyP
to understand rainbow you must understand how a 1 chip DLP works. It does sequentially a red picture, a green pictyure and then a blue picture. In the most part your eyes/ brain will see these three pictures and put them together as one picture. for insteance if there is a spot that is full read/green/blue you will see white.

now what are rainbows? well simply put, sometimes in some spots of an image you will see some of each of the components (i.e. flashes of colours)


when do they happen? in high contrast scenes (i.e. black and white movies are good for this), or (artificially) if you move your eyes a lot

Re: Black & White movies. I've been archiving a lot of old BW classics to DVD. Citizen Kane, To Kill a Mockingbird, etc. Most of them I see no rainbows at all. I did a whole batch of early silent films ... and saw no rainbows. Most of the home made DVDs I have made of favorite TV shows in color show "almost" no rainbows. However I used to be able to see RBE on a lot of the commercial DVDs I bought.

It's been a few months now ... and the degree of RBE is MUCH less. I think you can train yourself subconsciously to ignore them (if you can put up with them long enough to do so)

When I first got my X1, and could see the RBE clearly, the first thing I did was to try some of my classic BW movies. I was surprised they didn't have the problem.

On the high brightness and contrast .. I'll agree for sure on that. I have a "hot spot" on my unfinished screen. When I do see the RBE it's usually in that hot spot. (still haven't gotten around to painting the screen yet.

Whatever you do DO NOT! I repeat DO NOT! Do a lot of work from a HTPC inside a command prompt (Black Background/White Text) with a DLP projector. That right there is a good tough test for a DLP projector.

Here is a new rainbow demonstration:
http://img105.exs.cx/img105/8051/rbetestar2wz.gif

This is how I see the reainbows.
Short intense flashes of bright light (with some colors around it in a gradient way).

Are you referring to the flash from the object the girl takes?

You know its really weird, Ive seen rainbows in samsung dlp tv's but in most dlp projectors I've seen I've not noticed it. So far I've seen all the Sharp DLP's and a BENQ PE7800. Is this really that big of a problem?

After reading about 5 pages worth of this post...a small minority see them....and of that minority some find it is excrutiating and ruins their experience while others it doesnt bother too much and they can train themselves to not see them as much or at all. Im just trying to find out if I am susceptible to them or not without actually seeing a DLP projector...which Im guessing is impossible.

ted1001 finally a picture is worth a 1001 words .

Just say no to rainbow...

In my experience, it's not just rainbows. It is possible to learn to over look them, especially on projectors with better color wheel designs.

My main complaint, is the eye strain associated with the color wheel rendered image. There is a pressure to minimize your head/eye movement around the screen. It's particularly evident in the opening fight scenes of Gladiator.

My switch from the NEC HT1000 to the Sony HS-51, eliminated that eye strain immediately and has made for a much better personal viewing experience.

I was able to enjoy the HT1000 for a long time, just over two years. But this fall, I became more sensitive to the color wheel effect. I have no idea what changed. Perhaps my prescription has drifted just enough to cause an uncomfortable imbalance when watching a color wheel rendered image.

While I was glad I was able to enjoy the HT1000 for a long while, I am also glad the HS-51 is such a wonderful alternative.

Originally posted by AudioVogue
After reading about 5 pages worth of this post...a small minority see them....and of that minority some find it is excrutiating and ruins their experience while others it doesnt bother too much and they can train themselves to not see them as much or at all. Im just trying to find out if I am susceptible to them or not without actually seeing a DLP projector...which Im guessing is impossible. Yeah, a small minority see them and yet this 'topic' seems to get repeatedly discussed over and over again.

Nice spin, there.

Yeah, a small minority see them and yet this 'topic' seems to get repeatedly discussed over and over again. That's because we like to discuss things over and over again on this forum sometimes. I've still yet to find anyone away from this forum that is bothered by rainbows. We're talking a lot of movie parties and Super Bowls here. The Super Bowl is a great test due to its length when you include the pregame. (Even without it...)

Hearing about rainbows and actively looking for them is the biggest mistake.

Yes, some people see rainbows or have eye fatigue whether they want to or not but they are definitely in the minority. (In the real world)
I say "in the real world" because so many issues get blown out of proportion here.

My advice is always the same, try and see a DLP setup for yourself and don't go out of your way (head shaking) to see rainbows. You'll know if you are bothered by them. Don't let anyone else convince you that you are without judging for yourself.

I've also seen plenty of "I was afraid to buy a "DLP" because of all the talk of "rainbows" on this forum. I'm glad I didn't listen!"

I know we like to repeat-discuss, but it still takes a critical mass of individuals to make up the discussion. If you do not see RBE then why would one discuss it, let alone mention it?

Also, I'll repeat it for the benefit of some: not everyone knows what RBE looks like, but they may be seeing it (and even annoyed by it), but not put two and two together.

BTW, I do not have to actively look for them. I am that super-small minority (nyuck, nyuck, nyuck) that can see them even when not trying to look for them. I wish my brain would play nice, but it refuses.

For me the RBE is a little problem compared to the flashing/intermitent/unstable LCD pixels. I can´t open my eyes to my Epson EMP-800 LCD projection in bright scenes, I feel it is damaging my eyes, like the sun. DLP refresh rate is arround 1ns, when LCD is arround 10ms: 10000 times more stable!


At least with DLP I can start viewing a movie... :)

Sounds like maybe a little more research should have been done before you bought that LCD.

That's because we like to discuss things over and over again on this forum sometimes.

agree


I've still yet to find anyone away from this forum that is bothered by rainbows. We're talking a lot of movie parties and Super Bowls here. The Super Bowl is a great test due to its length when you include the pregame. (Even without it...)


that is youre experience, but I disagree, the super bowl is not a great test, it is one of the worst, it is not how long, but what is shown, and there is not much white on black

Hearing about rainbows and actively looking for them is the biggest mistake.

agree

Yes, some people see rainbows or have eye fatigue whether they want to or not but they are definitely in the minority. (In the real world)
I say "in the real world" because so many issues get blown out of proportion here.

agree, just like screen door ......

My advice is always the same, try and see a DLP setup for yourself and don't go out of your way (head shaking) to see rainbows. You'll know if you are bothered by them. Don't let anyone else convince you that you are without judging for yourself.

agree, and would say the same holds for every technology and projector, but I think seeing some movies or clips that would show how bad it can get is not a bad thing

I've also seen plenty of "I was afraid to buy a "DLP" because of all the talk of "rainbows" on this forum. I'm glad I didn't listen!"


agree, but I have also seen the same for LCD and bad CR or bad SDE

I know we like to repeat-discuss, but it still takes a critical mass of individuals to make up the discussion. If you do not see RBE then why would one discuss it, let alone mention it? I'll have to argue "critical mass of individuals".

If that were the case there would be legal action or at the very least callbacks of some kind.
The fact of the matter is, rainbows bother a very small amount of the general public who view DLP. Can we agree on that?

I actually ask a lot of the viewers who pass through my HT. (After the movie is over) Not one of them has ever admitted to headaches or seeing flashes of coloured light. Most of them look at me like I'm crazy. I'm pushing over 60 viewers since I began with my old LT150.

Let's not blow this out of proportion. This really does not bother "most" people. I do feel sorry for those that are troubled by DLP.
All the boardrooms around this office use DLP presentation PJ's. No critical mass of individuals screaming of headaches yet. And I work with Doctors. They would be the first to complain. ;)

Why? In my experience there are those who simply return the projector if they were not aware of the problem before their purchase. Then, there is the safe harbor TI can take as there is nothing they can do to overcome your saccadic masking condition.

BTW, CRT scan-lines and LCD SDE didn't seem to bother enough people to keep them from being successful technologies either. And yes, they do have their small minority representation about being bothered, too.

As long as we agree that it is a "small minority" then I don't have a problem.
That's my point.

If that were the case there would be legal action or at the very least callbacks of some kind.

1) it is a limit of the technology, there cannot be a call back (what will you do replace them with LCDs), we are also not talking about anything critical, so I cannot imagine even if it affected 50% of people that there would be a legal case. If it was brought before me and I was a judge I would just tell them "don't buy a DLP if you don't like it or it makes you sick, there are other techs out there"

2) DLP makes me sick and there are some DLP projectors (mostly the portables) but I never came out of a meeting telling them "your projector makes me sick) and don't forget people would probably think it was because of a bad presentation (man that was so bad my eyes are running and my head hurts). As for rainbows, they happen with movement and contrast, so except if someone goes fancy with PP there should not be any problems in conference rooms and even in fancy powerpoints, any movement would be minimal

As long as we agree that it is a "small minority" then I don't have a problem.

I don't think anyone has ever argued that point (except for a few people that say that RBE does not exist)

I have never insinuated that is was a big problem, meaning a large number of people or high percentage of people. But I do have to wonder if an agenda exists for saying its overblown or that its not just a minority, but a small minority. No independent research firm has condicuted jack as far as I know. Sure, some reports have come out and look to the roots of who paid for them. I invalidate them automatically.

I don't think anyone has ever argued that point (except for a few people that say that RBE does not exist) Quite the opposite, there are some people on this forum that act like "x" shouldn't buy a DLP because "x" is sure to be bothered by rainbows. That leads me to believe that they think "most" people are bothered by DLP.

Knowledge is everything to me. I'd rather be informed than not. I'd rather offer information to help someone else make an informed decision they are planning on making anything than withhold information and let them walk a plank. And I've stood next to people that observed 'something' and didn't know what it was until they described it to be and I offered information to help them more accurately identify what they were looking at (whether they are looking a scan-lines, screen, door, RBE, dithering, macroblocks, veritcal banding, raster illumination and air-light scattering, etc.).

Its bad enough the common consumer is treated to a dosage of ignorance followed by a dosage of misinformation that sitting back and playing apathetic is just, well, unreasonable to me. But, I guess only diamonds are cherished in their flaws. :)

if an agenda exists for saying its overblown or that its not just a minority, but a small minority

I do agree with the over blown, especially since things here are either over blown or not talked about at all. :-) so why should this have a different standard, but minority and small minority, anything under 50% is a minority and I just take it that they mean that it is no where near 50%. I have no idea what % of people are affected but I would think a small minority of people have even seen digital projection and of them much less then 50% are affected.

there are some people on this forum that act like "x" shouldn't buy a DLP because "x" is sure to be bothered by rainbows

I don't remember anyone acting that way

Anthony, I'm shocked! Really I am.

Ferret, Knowledge is great. But when a new user reads a few "Better make sure that you are not susceptible to rainbows" It can be a bit overwhelming.

Like I said before, we've all seen posts where a new member comes back and is relieved that they don't see any rainbows. When in actuality most people don't even have to worry about it. You would think by the way some threads go on that most people DO see rainbows. IMHO

Originally posted by TheFerret
Sounds like maybe a little more research should have been done before you bought that LCD.


Yes, I didn´t research at all. But it is 3 years old...


What is the lowest refresh rate of all LCD projectors nowadays? 5ms? 1ms?



Regards

I have read that the expensive Sony Qualia 004 has a pixel response time of 5ms. (5000 times the response time of DLP) The key is the fall time, but it is considerable compared to the rise time. DLP is so different..

http://ultimateavmag.com/videoprojectors/504sony/index6.html


People should be worry as well about response time. Something like this:
"Better you are not sensible to image unstability.."


I can´t work with LCD TFT displays(fatest have ~8-30ms response time), it is worse with a bigger projected image. I DO see clearly rainbows and blurred image with every movement, even with a 5x color wheel, but I see at least a stable image.


Regards

That's because we like to discuss things over and over again on this forum sometimes. I've still yet to find anyone away from this forum that is bothered by rainbows.

Discussion is what a forum is all about. I have found numerous folks outside this forum, who are affected by color wheel artifacts. Almost every major projector review, takes color wheel artifacts into account and grades a projector performance accordingly. So while fewer people may experience problems, the problem does exist for some and is a worthy topic of discussion in many forums and professional reviews.

As long as we agree that it is a "small minority" then I don't have a problem.

Why should we have to agree to your perspective?

I have not seen anyone present polling data from forum members or outside this forum, to properly support any qualification regarding how many people can see or are affected by DLP color wheel artifacts.

What we should be trying to determine, is why some folks are affected and others are not. Does it have to do with prescription contacts/glasses? Or inherent eye problems such as astigmatisms?

Every projector has pros/cons. A buyer should be able to have all of the facts to help select the best balance of pros/cons to serve their HT needs. One of the best places to get the facts, is on AVS.

Perhaps we could have a >$3500 forum poll to gauge what % of our readers are affected by color wheel artifacts?

Byte,
I didn't mean as long as we ALL agree. Just the members I was talking to. I wanted to know if we were on the same page.

We were.

As far as I'm concerned it is a very small minority. My experience comes up with this result. When you have fifty to sixty different people over to watch movies over the past few years and not one of them seems to be bothered (and keep coming back for more movie nights), I think it's safe to say that the problem isn't major. At least in this research group.

What we should be trying to determine, is why some folks are affected and others are not. Does it have to do with prescription contacts/glasses? Or inherent eye problems such as astigmatisms? I agree.

Every projector has pros/cons. A buyer should be able to have all of the facts to help select the best balance of pros/cons to serve their HT needs. One of the best places to get the facts, is on AVS. I also agree.
But when "rainbows" become a real "fear" for new users I think things have gone too far.

Originally posted by Kysersose
But when "rainbows" become a real "fear" for new users I think things have gone too far.

And this is were I will respectfully disagree.

Any projector artifact which could influence an owners enjoyment, needs to be fully understood in advance, rather than after the fact.

Although FEAR is a pretty strong word, when I think about spending thousands of $$$ and then discovering an artifact cripples my viewing enjoyment, fear does not seem to strong a word. In fact, I would be very angry if the existence of the artifact was nondisclosed or described as something very minor, only to find out it had a huge personal impact. This goes for any artifact.

I'll agree there is no need to create hysteria over one artifact type. However, reasonable discussion to map out ALL projector design artifacts, only serves to benefit a buyer in his/her decision process.

I'm just glad to see the marketplace offering a greater range of competitive choices, so folks can do their homework, ask questions, and come away with a decision to best meet their needs.

I'll agree there is no need to create hysteria over one artifact type. However, reasonable discussion to map out ALL projector design artifacts, only serves to benefit a buyer in his/her decision process. I agree with this.

I just know from personal experience that a couple of members have been talked out of buying DLP without even knowing if they are bothered by rainbows. That spells fear to me.

I won't mention any names.

We basically agree, check the projector out for yourself and make up your own mind. This is the best advice.

With so many DLP TV's and projectors today that shouldn't be a tall order.

I'm just glad to see the marketplace offering a greater range of competitive choices, so folks can do their homework, ask questions, and come away with a decision to best meet their needs. Once again, we agree.

And i bet i could easily find some touting (which is fine) and blindly recommending (which is not so fine) a product or technology without even understanding that buyer.

While is seems a great many are trying to be polite here and not upset the smoldering emotinos that the DLP religion can present (as does CRT religion, LCD religino, etc.), its still difficult accepting someone forwarding what I would consider hollow conclusions.

This particular thread reminds me of the burn-in thread seen in the CRT forum and RTPV forums from time to time. There isn't a need that I can see to put down a thread but rather just insure accurate information is provided for the buyers that may be reading it.

Like I said before, we've all seen posts where a new member comes back and is relieved that they don't see any rainbows. When in actuality most people don't even have to worry about it. You would think by the way some threads go on that most people DO see rainbows. IMHO

I agree, and I have seen such posts. But let's be honest, is it better A) for one person that is not affected to buy something other then DLP or B) avoid the subject not to "scare" people and have people regret their purchase because they cannot stand it and they cannot return the projector. I pick A, I don't gain anything if someone picks DLP or LCD or LCoS, but it is good helping someone not to make a bad decision

I have always said that people should look at projectors before they buy, simply put most of the stuff that are important to the pic is not in the specs (lenses: some focus better, scalars: some make softer/harder images.....) and we don't all have the same taste. And I have been shot down many times on this forum with comments like "not all people have equal access to high end shops and it is not always easy"

When I first purchased my X1 I looked really hard for rainbows. I did see them if I stared and shook my head. I decided I could live with them. As time went by I would occasionaly see them (mostly if I remember to look for them). I am at 2500+ hours on my first bulb and it wasn't until I saw this thread that I realized I hadn't seen them in a very long time. I don't know if its because the bulb may be dimmer, the color of the screen (I used to project on a plain white wall), the projector just got better, my eyes are so used to watching DLP that my brain has ignored them, or a combination of the above.
I have sent my X1 in for repair (Noisy color wheel) and miss it alot. Sending the projector via UPS was like putting a loved one on a airplane. I eagerly await its return.
I have to honestly say the X1 has been the BEST electronic purchase I have ever made and it has spoiled me so much that watching television while it is gone is painful.

Even if I did still see the rainbows, it would be worth it.:p

When I bought the X1 I didn't have to go looking for them at all, but rather it was like b!tch-slapped in the face with them. In fact, after a couple of week the intended role for the X1 in my home was completely hindered to a point of being worthless--which is why I returned it.

RBE is not linear in any sense of any notion. How well one sees or doesn't see RBE for a given product can be completely different for the next person. I would love to not see RBE, but until I get a labotomy, TI introduces a cheap, highly-effective drug for me, etc. DLP is not too serious of am option for me.

No one should rule out a DLP product based on a written word alone. If one is not going to audition then they are not being true to themselves, or their money.

HouTxGuy: not too be mean, but I don't think

I did see them if I stared and shook my head

I don't think this is what any one means with seeing rainbows. I thoink what pople need to realize is that for the rest that "do" see rainbows thaey are there most of the time and you don't need to do anything to see them.

HouTxGuy,
To be honest, I don't even think that seeing rainbows is the big issue. I can see
rainbows, but they don't bother me. (Nor does seeing SDE on my LCD.) I went
with LCD because my wife is one of the few for whom DLP does not work. She gets headaches and becomes quite sick very quickly.

Before I bought my projector we looked at quite a few DLP's with the same result each time. My wife never knew what technology she was watching so my decision was clear. Almost every place I could have purchased the projector from would have had a stiff restocking fee. This forum helped me avoid a big mistake since I probably would have gone for one of the first DLP's had I not been aware of the potential problem.

For newbies much of what one reads on these forums can create
unnecessary anxiety. Between vertical banding, SDE, low contrast
and poor shadow details, I am not sure how anyone would ever survive
with an LCD projector. But somehow, we manage to thoroughly
enjoy ours.

I agree that no one should rule out DLP before buying, but I am very glad
that this issue was discussed.

The ultimate rainbow torture test is watching Sky Captain and the World of Tomorrow (Widescreen Special Collector's Edition) (2004) .
The abundant use of green screens for CGI effects wreaks havoc with the rainbow coalition ....

Just say no to rainbow .

Most people, I suspect, do not see rainbows or see very little of them to be bothered. But there are those who clearly see them (I'm one of the unfortunate ones), and it all started soon after I 'learned' how to see them from this wonderful forum. My son keeps asking me what they are about, and I've decided not to teach him. Is that so bad? Not so, IMO, since he obviously can't see them. My son is not the only one who just can't see them, it appears, as I've come across many (actually the majority) who are just like him.

As for me, I'm most certainly not bothered by them, and I'm also thankful that I don't get headaches even after watching many hours on my 2x colorwheel projector. So far, all my guests have no complaints, but only praises for my lowly setup.

So, to be fair to our friends who are considering DLP, we should just advise them have a look at DLPs (the slow colorwheel ones) before they spend their money. I suspect the majority of them will not be unhappy.

Are there rainbows, apart from those after the Flood? Yes, if you can see them. And if you can see them, do they bother you? Personally, I'm very happy with the blacks and the smooth image I get from my DLP.

Allow me to give this thread a new push...

... folks who see and are bothered by rainbows or other color wheel artifacts:

Do you wear glasses or contacts?

Is there anything special regarding your eye sight?

Do you have dyslexia?

I'd like to see if folks who suffer from artifacts, have anything in common.

I wear glasses to see far. My eyes are uneven as far as how well they see close up, but they are well balanced to see far. I suffer from mild dyslexia when reading.

The main effect I feel is a form of pressure to keep my eyes and head steady, although under certain conditions I will get a head ache behind my eyes.

Maybe we might find somethings we share which contribute to our observance and discomfort with the artifacts.

I see them and at this point I do not mind TOO much. I am experiementing with a 4805 and see rainbows on dark scenes with white portions (like a neon sign in a night shot). For the price of the 4805 they are tolerable. If I paid more than $1500 I would be frustrated, and more than $2000 I would be pissed. For the price, I will accept this issue.

I've seen rainbows since the first Sammys hit the stores. All I had to do is quickly look back and forth to see them. The newer technology has considerably reduced them for me. Now I only see them in certain situations.

My vision is great. At 60 hz I can see flicker on monitors, which goes away at 85hz.

I see rainbows occasionally on my Sammy 43" DLP. They're not common but they do bother me when I see them. The contrast between white and black usually does it for me.

I'm looking at getting a projector for my home theater and am hesitant at getting a DLP because of it. I'll demo one in a store somewhere first.

The strangest place I've seen rainbows is in Walt Disney World's Haunted Mansion attraction. They recently upgraded their projectors for their singings busts effect to DLP and I definitely knew they did it. I've ridden this ride hundreds of times (I live in Orlando) and one day, rainbows suddenly appeared. I read online that they had recently swapped their projectors. It was BAD for me there. I couldn't even look at the singing busts without seeing rainbows. However, the next time I rode it, a couple weeks later, I saw no rainbows, and have not since. I cannot explain this.

I have astigmatism in at least one eye (I forget if it's both) and wearing my glasses definitely reduces the rainbows. I am near-sighted (need glasses to see far) and it greatly helps my eyes to wear them while watching any TV, video games, or movies.

I also can see monitor refresh rates up to 85Hz.

I purchased a lower end dlp as a second projector after having a 720 p lcd projector. rainbows were easy to see for me and very bothersome. most of my friends saw them as well.Still, it seems silly to read comments like "just say no to dlp" If others have a positive experience with these machines than i do not see the need to try to convince them to be unhappy. but then it always annoys me when my own mother wants to tell me what i should order off a menu.

It annoys me too and I'm 50 years old!! :) :)

I have experience with 3 DLP projectors so far, all with 2X color wheels. The first was a BenQ 6100, the second was a X1 and more recently a X3.

I thought that DLP was out for me, I saw rainbows like crazy with the 6100 and X1, and pretty much dismissed them and bought an LCD. Then we got a X3 at work and after reading over and over again that some people who saw RBE saw it diminish over time, I decided to try and sit through an entire movie with the X3, as I only had a few minutes with the other projectors.

For the first 10 - 20 minutes I saw RBE on the X3 just as before, and my wife said that she saw it a few times, but after about 30 - 40 minutes, it almost went away for me, and completely went away for my wife. I never got a headache or eyestrain either.

So, being that its a 2X wheel, I am convinced that I could handle a 4X without any issues, and I will certainly consider DLP when its time to upgrade.

I think that the members on this site that tell us RBE "people" to give it some time are right, especially if I noticed them diminishing only after 30 - 40 minutes......and I was looking for them! I have read here that some don't seem them at all anymore after a few weeks.

Finally, just to keep on the same level here, I am severely near-sighted and wear contacts. I can't sit in front of a monitor unless its 75hz or higher, and most indoor florescent lighting gives me a headache after awhile.........

I see rbe like crazy, x-1 and then 4805. most of my friends cannot. i actually could not see rainbows until i was told they were there and began looking for them.

I don't think an "Ultimate Rainbow" post can be ultimate without a link lke this: http://eo.ucar.edu/rainbows/

Hi,
I would have thought RBE would be more noticable the wider the viewing angle. Anyone having to move their eyes about the screen to take in the movie is more likely to see and be affected by RBE. Conversely anyone who typically sits staring like a zombie at the screen, taking everything in without moving their eyes, is less likely to see RBE. For people who don't like moving their eyes, I imagine, they would sit further from the screen.

Real Zombies would only be pretending to watch the screen while they scoped the room for living flesh.

I've seen RBE, but it was at a friends house and I wasn't able to experiment. I have a CRT FP.

Cheers,

John

I saw rainbows immediately the first time I plugged in my 4805. They were everywhere. My first thought was "gosh, why do I have to be part of the crowd that see them?!". It was also then that I remembered seeing them briefly on a friend's DLP TV, except I didn't know what they were then. Given that I could see them on a friggin TV, and how often they showed up on the Infocus, I suspect I am in the extra sensitive group. That said, it never occured to me to return the projector, I couldn't live without the picture size and those gorgeous colors!

Strangely enough, after 6 weeks of ownership, they pretty much dissapeared. So yeah, there is definitely some adjustement going on.

I am near sighted, but lost my glasses some months ago, long before I got the projector so I never did see with my glasses. That I can go a few months without glasses should tell you that my eye sight isn't really that bad. I used them mainly for watching movies and driving (mostly night) and will get new ones very soon...

I can see them with the 4805 some times more than others but just for a while..say 20 minutes perhaps less. Is like m brain needs to adjust and eliminate it and then everything is fine. But yeah, watching a B&W sequence like the beggining of Van Healsing is a killer for me if I do it right away...if I wait a little then its fine and btw, that scene has some detail doesnt it?
Regards

Looking at purchasing the DLP with 5X color wheel, how does the RBE reduce in relation to the speed of the wheel. Also, I looked at a DLP in a store for 10 minutes and did not see any RBE, but concerned about others.

Looking at purchasing the DLP with 5X color wheel, how does the RBE reduce in relation to the speed of the wheel. Also, I looked at a DLP in a store for 10 minutes and did not see any RBE, but concerned about others.
I see no rainbows on my H31.

Hi all
i'm a newbie on VP but i've buy an Optoma H27 since 1 month....
Getting some rainbow effect , i've found many post about it in this forum....
One of the supposed solution is an ND2 filter ... ? to reduce 50% of brightness....
If it's really working, why don't simply reduce brigthness on your VP setup ????
don't understand why buy something more, if you can do the same with the setup menu for free ?
may be because i'm newbie ;)
thanks for your explanation ;)

My wife has always been very susceptible to the RBE effect. And I am very happy to say she sees next to none with the Optoma H79 PJ. I have been thru DLP tvs, and other pjs (BenQ and Infocus) and feel a ton of relief. Must be the 8 segment color wheel with the DC3 chip... Whatever it is we are not complaining!

I could see the RBE quite a bit when I first got my Infocus X1 a little over a year ago. I hung in there and like magic about 3 months later they sort of "disappeared". After that even when I TRY to look for them I can't find any. I don't know if it was my subconscious screening them out, or the PJ breaking itself in or something, but now .. I'm RBE free.

I did a lot of studying of this and found it's most pronounced when the reflecting surface has a lot of gain or is very "polished". I used to also have a "hot spot" on my home made screen, which totally disappeared when I painted it with an eggshell white. The picture now is beautiful, no hot spots no RBE.

This thread sounds like it all gets down to "issues!"...and who's got em...and others are trying to put "theirs" (issues) on someone else.!!! That's not good.
I hear a lot of people here stating that "people with sand in their shoes should not be irritated by it!" And "people have no reason not to like chololate over vanilla",etc.
Well I see rainbows on most DLP pj's I look at. And the headache I get is very real too often. But then I've got to wear sunglasses in bright light, and my eyes get dry real easy too. Still, I don't get why some here are trying to make others who do see rainbows believe they can't, or shouldn't. Kinda dumb really.
I'm more interested in which PJ's tend to show the least RBE compared to others, from people who are sensetive to it!
That all said, the "piss poor" black level i see on LCD pj's is all too real, and NOT SUBJECTIVE! When are they ever gunna fix that problem? I will believe the hype on the new LCD's when I see em, not any sooner.
For now, I'm searching through all the DLP's that I can live with.
Anyone see the CL410 from Runco?

Is this an accurate test to see if you may not be happy with buying a DLP unit such as the Infocus 4805?

http://www.ausmedia.com.au/DLP_Sensitive.htm

That all said, the "piss poor" black level i see on LCD pj's is all too real, and NOT SUBJECTIVE! When are they ever gunna fix that problem? I will believe the hype on the new LCD's when I see em, not any sooner.
For now, I'm searching through all the DLP's that I can live with.

Have you seen a well calibrated Sony HS-51?

While there is certainly room for additional contrast improvement, the HS-51 has been a welcome relief.

I was initially able to adjust the RBE on my NEC HT1000. Then out of the blue I began having trouble. I tried several alternate DLPs, and nothing satisfied. Then I took a shot with a HS-51.

Wow. I was finally able to enjoy hour after hour of movie watching. Challenging scenes like the battle at the beginning of Gladiator were no longer torture.

DLP has gotten better in the last year, particularly with the H79. However, I am more likely to consider the Sony Ruby as my next upgrade.

Well I noticed the rainbows on my X1 when I first got it and yes they bothered me a little. You only see them if you switch your eyes or move your head fast. It only took a few weeks to get used them and after a month or so I rarely evan noticed them. I know some people complain about headaches, I never had that problem.

Is this an accurate test to see if you may not be happy with buying a DLP unit such as the Infocus 4805?

http://www.ausmedia.com.au/DLP_Sensitive.htm

Those optical illusions are pretty interesting. I can see movement on probably 25 % of them. Most noticable to me are the circles and rings and a few of the patterns that seem to move outward. The flashing black lights do nothing as far as I can tell.

I do have the 4805 and have only seen one rainbow in the year that I have had it and that happened very late at night (around 4:30 AM) when I was extremely tired and was using the THX Optimizer on The Incredibles. The image was a white circle on a black background and I could see the circle flash red, green and blue.

The next night I tried to duplicate it and could not do it. This led me to believe the only reason I saw the RBE effect the night before was because of being extremely tired.

The interesting thing about the optical illusions is that they only indicate if the viewer is motion sensitive, which I am. However, those illusons did not bother me, but the 4805 did (and it wasn't RBE! - which I didn't see). After self-analyis, I determined that the 4805 gave me a headache because of 2 factors: 1) it was way too bright, and 2) the panning blur - temporal dithering? - drove me crazy (saw it on a 7205 also).

Other 720p DLP PJs that I saw, did not bother me, so it's brightness and how the motion artifacts are processed that bother me, not RBE.

NOTE: I also have a slight problem with a too bright HC3 (1/4 HD LCD PJ), so it's a combination of brightness, resolution and motion artifact processing that effect me.

When i first got my 4805 about a year ago i did not notice RBE. Although a few months ago i did start to notice it. I cleaned my filter last weekend. Problem is gone. probably coincidence so im not saying that if you clean your filter it fixes it. but it did for me. But then again i kinda liked the RBE. There was a time in my life that i paid for drugs to make me see stuff like that :)

perhaps someone could tell me how fast the colorwheel is in DLP rptv's? I have never seen a rainbow in those, but was plagued by them with the X1 - i'm hoping that I won't see them when I get the screenplay 4805.

Just to toss my 2 cents in...

I generally have very sensitive senses and can often hear a TV or CRT monitor a room or more away due to it's high pitch whine. I also see flickers in flourescent lights and monitors that have refresh rates below 75hz. I tend to be more bothered by bad display and audio technology more than most of my friends and am even more suseptable to bad smells giving me headaches and causing discomfort.

I can definitely see RBE if I shake my head during almost any scene and find it worst during bright white on muddled background (usually in first person shooter video games of the WWII era as they tend to have bright white aiming reticules on grey/green/brown backgrounds. The high contrast reticule against the low contrast background is even worse for me than bright white on black).

When I first got my 4805 I found my eyes darting around alot becuase they weren't accustomed to such a huge screen, now that I am more comfortable with it and I can relax and still get the whole picture in my range of vision I find I notice it far less frequently and it's often more of a "oh there it is again" sort of feeling than an "oh man that hurt my eyes" feeling. Sort of like seeing a stuck pixel in an lcd that is usually more or less invisible as a solid color passes over.

I consider myself one of the ones who can see it but isn't bothered significantly by it most of the time. I have had to cut a few games out of my library due to it and it annoys me when a show seems to really force it to the fore front a lot (UFC fights seem to do it for me a lot with the contrasting ring/posts/lettering) but overall I am ok with it.

That being said I think that some people simply have more adept senses and can detect thigns (and hence be bothered by them) that others can't. Somewhat like people who can't tasted the acid in brussel sprouts that makes them impalitable to some.

No matter how small a market it effects I think its important to bring up because it can cause significant discomfort and be an expensive experience. Kind of like an alergy to nuts and nut oils that effects very few people it's important that everyone be educated about it and it's effects as they can be dramatic.

I have always been able to detect rainbow effect in DLP screens but never thought much of it because it is not a dominant technology in my life and when I did notice it was often in short periods in areas where I simply took it as a discomfort that came with the experience; places like presentations, conferences, store displays and entertainment centers (similar to the affore mentioned disney issue).

Generally I would notice it in passing, not so much that the source was unwatchable but it was noticeable. In stores I would see it a bit on a TV and think maybe it was the video they were showing, the lighting or my curent state of tiredness. During presentations I attributed it to the technology in the projectors but it never occured to me to think what it would be like to experience it regularly during my extended movie and tv watching. Also in those cases it was often in a well lit room where contrast of the display was washed out significantly by flourecent lights which I think decreased the perceptability of it.

This I think is significant because very few stores will provide the kind of setup you are likely to have when using your projector. During daylight when I watch my projector it is significantly more washed out than my blakout night time conditions however I can feel that it is far more gentle on the eyes (as I think any lower contrast display will be). I also notice that my darting eyes see less RBE during the daytime. At night however when it's very dark I can easily see RBE during fast actions seens and it makes some of my games near unplayable.

With restocking fees, shipping and sometimes a straightup inability to return a non defective unit I think this should be thoroughly explored. Many times a little thing can become much worse over prolonged exposure or different conditions. If this can effect your enjoyment of a multi thousand dollar investment I think it's well worth examining thoroughly.

I put it up there with buying a car, certainly not as expensive for the PJ alone but consider the money people put into a nice home theater setup based around the PJ and you could easily reach the tens of thousands, only to be foiled by something you could have noticed if you had been informed and really checked.

For me it would be like buying a sweet new sports car after an hour test drive, likeing everything I saw, buying all the aftermarket stuff for it, having my garage redone to accomdate my sporty new ride and give me that luxury custom feel to my car experience only to find out that a well known issue is that the AC in this particular car ONLY runs super cold and a few people who are sensitive to coldness get numb in their feet from it....

Not something I could I have found out during my test drive, not likely something I would ever notice and definitely something that could ruin my enjoyment of the car during my hot sommer cruises down the freeway.

You don't want to be too hot, you don't want your feet numb and it just sucks that if you had known about this you could have avoided it. Now if you can get the dealer to do a trade in (probably taking a loss on the value of your car) your aftermarket parts and custom garage may need to be redone and repurchased.

Yes I know that was long winded but it just seems that people who don't have this issue gloss over it and act like it's not an issue. As someone who has had issues with almost every technology short comming (from TFT LCDs shadows to flourecent lights to speakers that have performance issues inaudible to may others) I think its important to make sure everyone knows all the possible shortcommings when they make big purchases so that they can enjoy them.

Nothing sucks more than the feeling of being stuck with something that sucks, whether it sucks or just sucks for you.

If it doesn't bother you, good, if it doesn't bother 99% of the population good, but there is a reason wheel chair ramps and brail labling is as important as it is... sometimes the little things in life can really suck when you are that 1%.

perhaps someone could tell me how fast the colorwheel is in DLP rptv's? I have never seen a rainbow in those, but was plagued by them with the X1 - i'm hoping that I won't see them when I get the screenplay 4805.

Last I knew they were 5x...

maybe i'll be safe/okay with the 4805

I'm using the Optoma DV10 which has a 4x speed 7 segment color wheel. Owned it about 2 weeks and the lamp count shows 20 hours (includes calibration with DVE).

I am super pleased with the quality having watched LOTR, Moulin Rogue, Fifth Element, Criterion Collections' Bad Timing. Then last night, I put on SIN CITY. Extreme black and whites with super high contrast. Started seeing rainbows everywhere. Scared the tarnation out of me ~ since up until then, I had only read about RBEs and never seen one. I mean I thought I was a lucky one who was impervious to RBE. My viewing enviroment is a veritable light controlled cave.

Now after having read through all these posts, I realize that that SIN CITY is simply a RBE-friendly movie and displays one of the weaknesses of DLP technology. I don't see RBEs in normal programming and will test later tonight to make sure that RBEs are not seen in normal (not black and white) DVDs.

Funny, I didn't see RBEs even during DVE calibration which features black and white patterns. But let me assure the doubters, RBEs are definitely real and exist. For some it's a tolerable annoyance, for others its a toture to be avoided at all costs.

I hope in my case, it's just due to the high contrast black and white nature of SIN CITY and doesn't become an unwanted guest in every movie I see on my DLP.

I just bought the sp4805 and I also own the Optoma ep719 (2x wheel)

Its pretty clear that if you're planning on watching video DONT get a projector with a 2x color wheel. Too much eye strain and if you dont feel it others WILL.

I still see some rainbows with the sp4085 but the eye strain has been reduced to zero and I am happy for that. The rainbow now is just a minor visual effect instead of discomfort.

Why on earth manufacturers still make projectors with 2x color wheel is beyond me!

and I agree, Sin City is THE worst movie to watch on a DLP projector. I dont care what projector you have you WILL see rainbows in sin city. A 6x color wheel isnt even going to stop them, no way.

Why on earth manufacturers still make projectors with 2x color wheel is beyond me!Because "most" people don't see rainbows and have zero issues with it.


and I agree, Sin City is THE worst movie to watch on a DLP projector. I dont care what projector you have you WILL see rainbows in sin city. A 6x color wheel isnt even going to stop them, no way. Believe it or not there are some people who don't see them at all. Even while viewing Sin City

Yes, it's true.

...and I agree, Sin City is THE worst movie to watch on a DLP projector. I dont care what projector you have you WILL see rainbows in sin city. A 6x color wheel isnt even going to stop them, no way.


Unfortunately, Sin City is also a movie which shows any flaws in grayscale tracking, and most of the low cost alternatives to single panel DLP have issues with grayscale linearity.

Add an auto IRIS into the mix, and grayscale tracking is even tougher if there are color shifts associatied with the IRIS open/close position.

Believe it or not there are some people who don't see them at all. Even while viewing Sin City

Yes, it's true.

No problem with Sin City here (H31 - 4x). I'm actually very prone to motion sickness, so I'm not sure why rainbows don't affect me. My wife and I actually watched 7 hours straight of "24" on Saturday - no eyestrain or headaches to speak of...

-Mike

No problem with Sin City here (H31 - 4x). I'm actually very prone to motion sickness, so I'm not sure why rainbows don't affect me. My wife and I actually watched 7 hours straight of "24" on Saturday - no eyestrain or headaches to speak of...
-Mike

Count yourself among the fortunate and be sure to perform your annual sacrifices to the DLP gods for your blessing. :)

As a follow up to my posts above, I put in Stuart Little 2, recalibrated with DVE and then watched a bit of Constantine and haven't seen any RBEs since the Sin City affliction. A big whew!

But I am aware of eyestrain. I do notice that if I focus more on the story than the "picture quality" and stop tweaking my PJ settings endlessly that I am less aware of the eyestrain. Maybe the eyestrain is simply due to prolonged watching in a dark room.

Update: I changed the screen from a Draper matte white 72" width to a Graywolf 92" diagonal. The corresponding decrease in brightness (PJ has to cover a much larger picture) and going from white to a gray screen has eliminated rainbows when viewing Sin City.

Therefore, I agree that one way to reduce RBEs with a bright projector is to lower the overall light output using an ND filter. The kind of screen you are using also plays a part in the perception of RBEs.

Right now I'm just a happy camper enjoy my DLP PJ on a daily basis.

You don't get to see how many threads we delete and close on a daily basis. I own an LT240K and have no problems with rainbows.
IMHO "Rainbows" are blown WAY out of proportion in this forum.
I've still yet to meet ONE person who can see them that is NOT a member of this forum.

Just look at it this way... this is the only place to talk about rainbows from now on. If you don't want to read about rainbows then this should be the only thread that you have to avoid. We're not picking on DLP, we're just trying to avoid multiple rainbow threads day after day.


I would rather tolerate an occasional rainbow than a persistent screen door effect!!
I find SDE really annoying.

I have a sure fire way to see the DLP rainbows and I use it on PJ's I bring home to checkout. (so far only 2X PJ's tested)

My wife bought me Atari revolution as a gag gift for Christmas, yes the old system loaded with those very cheesy games. My sons always make fun of dad's "groovy" game system compared to XBox.

We fired up Pong and holy fa-shisel, following that white square ball across a 9' screen .... it looks like a comet with the colored tail. This was on a 2X DLP projector. It only appears on a fast moving ball too! Slow moving it is not so noticeable.

I ordered an IN76 last week. Sometime in the future we will run the pong test!

Oh and the only headaches created were caused by me crushing their butts in Asteroids. Let's not speak of Halo.

Seriously, with a gain of 1.5 screen and high lamp mode we had 2 headaches out of 15 viewers one 6 hour movie night. Once we went to low lamp mode and reduced the screen gain, the eye strain headaches were eliminated.

k

:confused: What is it that will help improve Raimbows on DLP, the speed of the colour wheel or the segs?

Would a Colour wheel with 6 segs and 5 speed be better for less rainbows than a 6 seg 4 speed wheel?

I see rainbow with the 4 speed but wonder if the 5 speed would be better?

Time...time will fix you. I can see RBE, even on rear projection units however whenever I quite looking for them and focus on the movie im watching I rarely get a glimps anymore. It isn't that big of a deal IMOH, and i can see them quite well. Oh but I think that the faster the color wheel is the better it is for RBE to be eliminated.

One way to solve the color wheel artifact is to eliminate it by going to a 3 panel DLP projector.

Color wheel limitations have been discussed at length and I don't think we yet have a solution for those who are affected by color wheel artifacts.

Perhaps there will be one final push to help improve color wheel performance of the next generation 1080p DLP projectors.

However, with 1080p 3 panel LCD, LCos & 720p DLP making some headway below $10,000, forcing the color wheel issue may become a moot point.

Incidently, I was able to enjoy a NEC HT1000 for 2 years before I began to have trouble watching it. I auditioned the BenQ 8700+ and InFocus 7205 and they were not any better. I almost tried the H79, but bought the HS-51 instead. I now own the HS-51A. I look forward to upgrading but the 51A will hold me over for a year or two.

I have posted many times about my wife and her severe RBE.. The H79 has been her best pj out of all the ones I have had. I contribute the 8 segment wheel with 5X speed with her lesser RBE. I would like to try another 720p pj but many of the newer ones are 4X with 6 segment color wheels. She would kill me if I ever changed. I would think the sony ruby would solve this but I am a big DLP fan. So yes bytehoven I guess I will be "stuck" with the H79 til the 3 chippers are here and more cost effective. I could try a single chip 1080p but it would have to great for me to attemp it...

I have posted many times about my wife and her severe RBE.. The H79 has been her best pj out of all the ones I have had. I contribute the 8 segment wheel with 5X speed with her lesser RBE. I would like to try another 720p pj but many of the newer ones are 4X with 6 segment color wheels. She would kill me if I ever changed. I would think the sony ruby would solve this but I am a big DLP fan. So yes bytehoven I guess I will be "stuck" with the H79 til the 3 chippers are here and more cost effective. I could try a single chip 1080p but it would have to great for me to attemp it...
so do you think 5x speed almost fixes it?
The segs have nothing to do with fixing it do they?

The segments on the 79 have the two dark green segments. You will get some that will say that there should be no difference from 4X to 5X or 6 segs to 8 segs. Then some will say that 4X is better. But after going thru all this RBE with my wife (I even took her to an eye doc) I can say that for her the 8 segment has made a world of a difference. That and probably the 5X speed. The other pjs had 6 segments and 4X and then 5X speed. She would get bad headaches and couldn't finish a movie. The H79 she will still see them but they are far less strenuous. I may very soon here permanately mount a ruby and be done with it. But she does also love the picture on the 79 and it blends in nicely with the ceiling. The newer Optomas 7100 and 7300 I could get for a great price but with only 6 segs and one being a 4X speed I would be worried she would slip back into RBE mode. I guess they figured they had to keep costs down to remain competitve with all the cheaper 720 pjs hitting the market. I still think for anyone with severe RBE 8 segments is the way to go.. Plus 5X speed...

I just picked up my first projector (optoma ep719). I've been just using it to test out a slideshow dvd and haven't noticed anything wrong with the picture. With just looking at the slideshow in a normal fashion I don't see rainbows, but could when i shaked my head. So I was pleased with my purchase until i noticed a little flicker on some white letters. When I paused my dvd player, a white "jvc" logo pops up and I'm seeing the some sort of flicker on all the white areas. I don't know why I didn't notice it before but now I can't stop seeing them. I wasn't sure if this was some sort of a rainbow effect as well. I took a closer look and it seemed to be different colors flashing in the white area. Is this because of the slow color wheel? Is this normal for this projector? If it's normal for this projector then I'll probably just end up keeping it but if there's something wrong then I'll exchange it or get something better. If I add a nd filter will it help it at all? Sorry for the novice questions. thanks

I have a SONY LCD pj and love it. Blacks could be better but ...... My bro-in-law has your projector and experiences no rainbow problems. BUT, that being said, the one time I watched a movie on it I had a splitting headache afterwards for several hours. Sooo, I will stick with LCD technology until the better DLP or plasma get cheaper.

I have a SONY LCD pj and love it. Blacks could be better but ...... My bro-in-law has your projector and experiences no rainbow problems. BUT, that being said, the one time I watched a movie on it I had a splitting headache afterwards for several hours. Sooo, I will stick with LCD technology until the better DLP or plasma get cheaper.

I have the Sony 51A LCD and I also find it's a reasonable compromise until 3 panel DLP projectors come down in price.

My issue with single panel DLP was not rainbows, but rather headaches as you have mentioned. Especially with brighter DLPs like the BenQ 8700+ and InFocus 7205/7210.

Some have reported the H79 is a great DLP and much easier to watch, but I have not tried it.


Instead, I decided to switch from the Sony 51 to the 51A for a little more contrast, and have invest in a very good calibration to take the grayscale tracking issues associated with LCD projectors. If I had the extra cabbage to spare, I would probably buy the Sony LCos Ruby projector, which also has wonderful contrast, and better grayscale tracking and uniformity than LCD.

Hopefully the next generation LCD projectors will solve some of the current LCD problems. Until then the 51A is doing very nicely.

I have a SONY LCD pj and love it. Blacks could be better but ...... My bro-in-law has your projector and experiences no rainbow problems. BUT, that being said, the one time I watched a movie on it I had a splitting headache afterwards for several hours. Sooo, I will stick with LCD technology until the better DLP or plasma get cheaper.


Is what I'm describing (white areas and letters flickering) the "rainbows" that everyones talking about? I thought they were seeing rainbows during fast movements or when your eyes move quickly across the screen. When I go up to the screen I can see the stationary white areas flickering. Can you can look or remember if your brother-in-law's projector did this? thanks for the reply

Hi all
Great thread
I would really like one of these projectors but am worried about RBE with the 4x colour wheel.I was affected with the earlier slower models but have been unable to get a demo of these.
Anyone who is suseptable to RBE i would love to know if you can see them with these models and if so how bad is it.
I got a demo of the Z2000 with its 5x wheel and only saw it a couple of times and i was really trying hard to see them.(could live with that)
Please help.I am so close to buying one of these.

Cheers mark

Hi guys! I posted a few rainbow questions in other threads and was chastised for it and even had my question belittled my 2 snob members who shall remain nameless. I recently sold my optoma h57 PJ which had a great pic. but unfortunately for me, produced the dreaded RBE on some occasions. It varied depending on the material but any really dark show like Buffy or Angel gave me problems. I stuck with it and it got better. I am now looking at the IN76 or the HC3000. I'd love to get the h78, (5x speed) but all of the overheating and prematurely aged bulbs have got me worried. Anyone who IS RBE susceptible have any experience with the IN76 or the hc3000? I would appreciate your opinion!
Thanks Dave

This evening I experienced RBE... while driving! I suppose it isn't true RBE, but I can see it quickly becoming a problem when more cars start getting this.

First, I will say that I can see rainbows if I look for them. I have a 1X DL500 (first generation DLP with a 1X color wheel) I've had it for about 5 years, and have no problems watching, but I can see rainbows if I dart my eyes on purpose.

Okay, the problem. I was behind what I found out was some sort of Cadilac sportscar. I noticed whenever I looked around, the tail lights would break up into several images of lights! When the brake lights came on, the problem ceased. So apparently the normal running mode is to have the LED brake lights strobe, and come on full time when stopping to make them brighter. When I say they strobe, you don't notice it if you just look straight at the light. Only if your eyes move. Just like with a DLP projector - you have to move your eyes around to see rainbows.

I just have to wonder what night time driving would have been like if ALL the cars had these new strobed LED tail lights! For those of you bothered by RBE, might want to check this out. This could become a safety issue for night time driving.

Imagine if someone is drinking while driving and they see this... :eek:

Woah! That's insane! Great! Something else I have to worry about!


;)

I've owned the PB6200 for about a year, and I've been using it in a HT setup for that entire time. For the first couple of weeks after I set up the HT, RBE drove me nuts. I'm the only one in the family who see the darn things, and I thought I was going to have to drop the whole HT idea until more affordable projectors become available.

Well, today, a year later, I don't see 'em anymore. Wierd, huh? Actually, if I "look" for 'em, I can see 'em, but they have not bothered me in recent memory.

Maybe my eyes/brain have learned to ignore them? Who knows, but I can tell you that they were a problem 1 year ago, now they're not.

:)

I just have to wonder what night time driving would have been like if ALL the cars had these new strobed LED tail lights! For those of you bothered by RBE, might want to check this out. This could become a safety issue for night time driving.

Believe me, I know what you are talking about. The new LED lights on some cars are driving me nuts. Our city's buses are now using them. And I only found this out first by the first hand experiencing the bizarre trailing/strobing effect of seeing those brake lights in front of me, especially at night time. If there is a bus in front of me, every time I dart my eyes past it the tail lights break up into annoying strobed trails across my vision. This does not happen at all, even if I try to elicit the effect, on cars with typical rear lights.

As you say, I can only imagine how distracting things could be with every car using those lights (and...yeah...I have problems with rainbows on DLP displays).

Interesting - here in England I've noticed some LED traffic lights have started to pop up around the place. I always notice them strobing as well. Isn't it funny how annoying it is once you've noticed it?

Also, I've definitely seen this rainbow effect (on 1 projector at least) and I can see slow-refreshing monitors. I'm slightly short sighted and possibly slightly dyslexic. Maybe this is a pattern emerging? Or maybe it's just a pattern in the kind of people who frequent these forums! ;)

I would like to figure out if I am affected by this "rainbow effect" but I can not find anywhere locally that has a DLP projector on display/demo. I was leaning towards the HD1000u but not knowing if it will drive me crazy sucks.

So for the time being, I may just buy a LCD projector and stick it out until I know for sure. =P

As I said all along .. It's an optical dillusion...


Uhh, no... it's "dELusion."

Haha, that's a funny phrase, though. I like it. That, and the "pigment of your imagination," LOL (even though light doesn't use pigments). :)


Actually I can see RE (not "RBE," just "RE," since "rainbow" is only ONE word--it isn't "rain bow"--and more accurate would be a term like "SE," "spectrum effect," anyway) once in a while, and it doesn't bother me--I don't run into it so often that it would drive me nuts. Heh, if I saw it all the time, then yeah, it would be rather distracting!

Well, I don't even see all the spectrum colors when that happens, usually just green and then blue or blue and then green (so therefore, it isn't really even true rainbow effect). When it happens to me, and since it only happens in those very short little bursts when I move around quickly (not while I'm trying to keep a still focus on the screen), I just find it a little interesting and/or amusing.

Ya know something? I wonder if several of the higher-resolution electronic signs are made of DLP, because I often see this effect while driving past them! What do ya think?

Uhh, no... it's "dELusion."

Haha, that's a funny phrase, though. I like it. That, and the "pigment of your imagination," LOL (even though light doesn't use pigments). :)


Actually I can see RE (not "RBE," just "RE," since "rainbow" is only ONE word--it isn't "rain bow"--and more accurate would be a term like "SE," "spectrum effect," anyway) once in a while, and it doesn't bother me--I don't run into it so often that it would drive me nuts. Heh, if I saw it all the time, then yeah, it would be rather distracting!

Well, I don't even see all the spectrum colors when that happens, usually just green and then blue or blue and then green (so therefore, it isn't really even true rainbow effect). When it happens to me, and since it only happens in those very short little bursts when I move around quickly (not while I'm trying to keep a still focus on the screen), I just find it a little interesting and/or amusing.

Ya know something? I wonder if several of the higher-resolution electronic signs are made of DLP, because I often see this effect while driving past them! What do ya think?

RBE like WWW is just the accepted acronym...

RBE is not limited to DLP, DLP just gets the lion's share of blame because it makes it easier to see for those afflicted. You can see RBE on CRTs and other display technologies as well.

RBE like WWW is just the accepted acronym...

RE is not limited to DLP. DLP just gets the lion's share of blame because it makes it easier to see for those afflicted. You can see RE on CRTs and other display technologies as well.


1. "RBE" and WWW are not acronyms. They're just plain initialism abbreviations. Acronyms are initialisms that are not only abbreviations, but which are pronounceable as if they're words themselves. For example, LASER and RADAR are acronyms.

2. Regardless of whether "RBE" is what you believe to be supposedly what you call "the accepted" abbreviation (in your own words), that doesn't mean it's correct. RE is more correct, and should've been generally accepted, and can still be generally acceptable. RE (or even better, SE, for "spectrum effect," since this effect is not an actual rainbow) is what should've been the generally accepted abbreviation.

3. Your point to try to compare "RBE" with WWW actually doesn't make sense, because while the words in WWW are three separate ones (world, wide, and web), hence why WWW makes the sense that it does, the words that some people errantly abbreviate as "RBE" instead of RE are only the two words, "rainbow" and "effect." Therefore, "RBE" and WWW don't compare directly even though you, for whatever incorrect reason, errantly thought they do.


Yeah, that's why I asked if the newer full-color electronic signs--at least the high-resolution ones--are DLP-based, since with DLP, RE has a lot more potential to be seen than with the other technologies. I don't remember seeing RE very easily, if at all, on older, low-resolution full-color electronic signs, most of which are made up of individual LEDs. I can't remember any time I've ever seen RE with CRT or LEDs. I'm not saying that it's never happened, though. Maybe I've seen it with LCDs, but I don't think so, except that like I'm saying, I don't know what the new high-res signs are made of (could be LCDs, but I wouldn't be surprised if they're DLP, although that would be pretty interesting).

How could RE be caused by a CRT, anyway, since CRTs have a somewhat persistent glow that DLPs don't have (which I don't know if LCDs have or not, but CRTs would have the most of because of their phosphors), and since CRTs can show all colors at once rather than having to quickly flip between colors in the same space? Why would LCDs and plasma screens have that, if they don't quickly flip between colors in the same dots like DLPs do (especially plasmas, since they have a somewhat persistent glow more like CRTs)? And how could LEDs ever cause RE, based on the same reasonings as in my questions about the other non-DLP technologies?

3. Your point to try to compare "RBE" with WWW actually doesn't make sense, because while the words in WWW are three separate ones (world, wide, and web), hence why WWW makes the sense that it does, the words that some people errantly abbreviate as "RBE" instead of RE are only the two words, "rainbow" and "effect." Therefore, "RBE" and WWW don't compare directly even though you, for whatever incorrect reason, errantly thought they do.



WWW stands for Worldwide Web - worldwide is ONE word.

I have been writing HTML since it was version 0.9

...
How could RE be caused by a CRT, anyway, since CRTs have a somewhat persistent glow that DLPs don't have (which I don't know if LCDs have or not, but CRTs would have the most of because of their phosphors), and since CRTs can show all colors at once rather than having to quickly flip between colors in the same space? Why would LCDs and plasma screens have that, if they don't quickly flip between colors in the same dots like DLPs do (especially plasmas, since they have a somewhat persistent glow more like CRTs)? And how could LEDs ever cause RE, based on the same reasonings as in my questions about the other non-DLP technologies?

You are talking about a specific cause of the "Rainbow Effect" as produced by DLP - it's called nystagmus. On a CRT it's also called moire, but, you still see a similar behavior or "rainbow".