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Discussion Starter · #1 ·
Any recommendations on a "reference" DVD to test whether I can see the rainbow effect on a Sammy DLP? The Sammys seem to have everything I'm looking for, but I cannot justify the purchase if I am susceptible to the rainbow effect (I watch a lot of DVDs).
 

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FWIW, I never noticed the rainbow effect when viewing the set in stores; once I got it home, I started to notice it but, luckily, it doesn't bother me at all. It's so fleeting and only happens in limited circumstances that it just isn't a big deal - I assume it bothers some people more than it bothers me.


In general, if you're looking for it, you want to look for light on dark. Something like The Matrix might work. But the surefire way to see it, if you are going to see it, is just to pause any movie where there are white titles (i.e. the credits after the movie) on a black background, then quickly move your eyes from onscreen to offscreen.


I also notice rainbows more when my eyes are more tired, i.e., late at night.


I also noticed something really funny yesterday - I had a spoon, tablespoon size, regular silver spoon, and my back was to the TV, and I noticed rainbows on both the concave and convex surfaces of the spoon, which was reflecting the light from the TV. I could actually stare at the rainbows if I moved the spoon quickly up and down like this.
 

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That spoon phenomenon is not related to the rainbows one can see from

spinning color wheels on DLP sets. Waving a shiny metal object has the

ability to separate parts of the spectrum from any light source.

Wave your spoon under a fluorescent light sometime, that effect should be

really pronounced.
 

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Quote:
Originally posted by jjf12cu
I had a spoon, tablespoon size, regular silver spoon, and my back was to the TV, and I noticed rainbows on both the concave and convex surfaces of the spoon, which was reflecting the light from the TV. I could actually stare at the rainbows if I moved the spoon quickly up and down like this.
There is no spoon.:D
 

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Out of curiosity, I just tried that... it didn't work. I would think you'd need some some refraction going on to seperate colors.
 

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I was first able to see it in the dark scenes from The Hunt For Red October. That said, rainbows weren't a major problem for me or my wife, and would not keep us from purchasing a Samsung DLP. I'm just waiting to see if the new LCoS sets arrive before I pull the trigger.


If you have to create a situation to see rainbows on the DLP, you probably won't be too affected by them.
 

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I think you will see it if you move you fingers in front of your eyes very quickly. I can see it on front and rear projection DLP projectors. Also, I can see it better in my peripheral vision (looking at the side of the TV and seeing it on the other side). I think if you use the TV as expected it shouldn't be that bothersome. It isn't something to worry about especially if you cannot see it in the first place. Don't look for problems--sometimes it is better to live blissfully.


Cheers
 

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Quote:
Originally posted by zvogt
That spoon phenomenon is not related to the rainbows one can see from

spinning color wheels on DLP sets. Waving a shiny metal object has the

ability to separate parts of the spectrum from any light source.

Wave your spoon under a fluorescent light sometime, that effect should be

really pronounced.
Ah - but this is different than the typical rainbow seen during diffraction (like with a prism) - as anyone who has a Samsung probably knows, the "rainbow" is not actually a rainbow at all in that it does not have the full ROYGBIV spectrum, but you actually just see red, blue and green next to each other. Same thing in the spoon...
 

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Quote:
Originally posted by jjf12cu
FWIW, I never noticed the rainbow effect when viewing the set in stores; once I got it home, I started to notice it but, luckily, it doesn't bother me at all. It's so fleeting and only happens in limited circumstances that it just isn't a big deal - I assume it bothers some people more than it bothers me.
same here,i NEVER saw them in stores either but started to notice them a day or two after getting my set.i`ve had the dlp almost 2 weeks and i rarely notice it now,maybe once or twice a night if that.

I haven`t done any major SM tweaks yet(just gamma and delay),can someone point me in the right direction for some more shadow detail help?

no DVI dvd player yet,will that help?no dvi stb either.

i`m using a panny dvdrp56 through component 1 and TOS dst3000 in comp 2.
 

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Quote:
Originally posted by Mfusick
Gladiator is the worst movie I have seen ..... on my DLP
Wow, I just watched Gladiator last night on my DLP and it looked really good. (Or are you just saying the movie sux?)


Anyways, to answer the post, if you want to see rainbows you can use a test DVD live Avia or DVE. Just put up the white cross hatch pattern or the aspect circle. Move your eyes and you should see rainbows. Note that this is of course an extreme example, and won't approximate normal viewing. For a normal DVD, I've heard MIB and MIB II are "good" for rainbows.
 

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Discussion Starter · #13 ·
Thanks for the replies. I am not "looking" for rainbows per se - I just want to see whether I notice them during normal viewing, i.e., I don't plan on doing anything while watching the "reference" DVD that I wouldn't normally do (no shaking head side to side rapidly). While checking out a Sammy at BB, I did notice rainbows while watching the short ESPNHD promo commercial that's a 5 second spot with the ESPN logo moving against a black background but I don't consider this promo normal viewing.
 

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If you really want to know if you can see the effect or not, just put in any DVD that has the THX Optimizer feature. Play the optimizer test called "aspect ratio" or something like that... This test is a black screen with a thin, white circle in the middle. Then quickly look at one far edge of the screen, then the other, moving your eyes, not your head. If you don't see the effect in this process, I would be confident that you'd never see it...


Just to clarify, you said that you cared about this because you "watch a lot of DVDs", the effect is an artifact of the single-chip DLP design, it affects any source under the right conditions, and will occur on any current single-chip DLP design.


I see the effect easily, and I live with it just fine... Do I wish it wasn't there - yep! Would I trade out my DLP for something else currently on the market in the same price range - nope!


Jeff
 

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 here is an example of the rainbow effect using the THX optimizer on the sammy DLP. like many have stated, this is an extreme example and not reflective of real-world viewing, just thought i'd share...
 

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dyevin, great example!


I just saw my first rainbows last night!! Of course I was trying to see them though. I had to move my eyes quite rapidly to see it. Under normal viewing conditions I never see them. Maybe those that seem them easily just have very twitchy eyes! :D
 

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Quote:
Originally posted by jjf12cu
I also noticed something really funny yesterday - I had a spoon, tablespoon size, regular silver spoon, and my back was to the TV, and I noticed rainbows on both the concave and convex surfaces of the spoon, which was reflecting the light from the TV. I could actually stare at the rainbows if I moved the spoon quickly up and down like this.
This is a motion effect, not diffraction or refraction as some have hinted. When you move the spoon quickly up and down, one of the many frequencies in your motion lines up with the frequency of the color wheel in the DLP set. Repeated long enough for your eyes to focus in, and you will see the separate colors appearing in different places in the motion, as if they are suspended in place. For example, spoon high catches the red, spoon lower catches the blue, spoon low catches the green. The spoon makes a handy instrument because it reflects light well.


The same effect is easily seen with florescent lights. These cycle between two emission states 60 times a second. Wave your hand or a pencil fast and repeatedly under a florescent and you will see alternating light and darker colors. To me the colors look like pale yellow and blue. This is a cool way of teaching how florescents work and why they can cause some people to have headaches. BTW, that same thing happens to me when I watch a DLP set - I see rainbows whenever I move and end up getting a headache pretty quickly.


Heaven help those who watch DLP with the florescents turned on! :eek:


HDD
 

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What were you doing when you were shooting that video? ;-)
 

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Quote:
Originally posted by Amazingly Smooth
What were you doing when you were shooting that video? ;-)
Apparently fending off the Blair Witch...


:D



It certainly does show the effect, but I don't have to make those kind of movements to see it myself!
 

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Quote:
Originally posted by dyevin
here is an example of the rainbow effect using the THX optimizer on the sammy DLP. like many have stated, this is an extreme example and not reflective of real-world viewing, just thought i'd share...
The color separation in this clip is more likely a limitation of the camera

rather than the display. But, that being said, it is still a similar principle

and actually does a good job of representing the concept of the problem,

even though what it's showing isn't technically the same.

The clip is a good tool to teach people what symptoms to look for.
 
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