It's official. I see a rainbow-like effect on every plasma. - Page 14

This is what I've been saying all along. Except LCD does not use PWM at all as it is an active-matrix display (pixels are "on" for the entire frame period). And plasma and dlp are not pure PWM as above but time code based (binary). So the example would be something like this

R RR R
G GG
BB

wikipedia is hardly an authoritative reference, and if you read below in the same article it also states:

"Three-chip DLP projectors can resolve finer gradations of shade and color than one-chip projectors, because each color has a longer time available to be modulated within each video frame; furthermore they have a reduced potential for flicker and rainbow effect"

Now, again, as I stated above 3-chip DLP also creates colors temporally. The positions of each DMD mirror element has only two positions, and there are three DMDs aligned together. That is 2^3 or 8 possible combinations. The combinations are: White, Black, G, R, B, C, M, Y. All other colors are created by dithering these 8 colors temporally.

Note how 3-chip is different than 1-chip in that white is not created by sequential R,G,B. Note also how each DMD element has the full time available to it, and is not restricted by colorwheel timing. These factors lead to greatly reduced or practically eliminated rainbow-type artifacts. The artifacts too, are different in nature from those in 1-chip DLPs, but they are not fundamentally gone or fundamentally something else. They are still the effects of temporal dithering to create colors other than the fundamental colors possible at any instant in the system.

I stand fully by what I said above because it is correct and true. Now, if you want to quibble about semantics about whether the artifacts possible in 3-chip is not the "rainbow effect" that's fine, but that's not an argument I'm interested in having.

There's some great info in this thread lately.

Now I know that I am not crazy. I have been reading the plasma forum since I don't know when and only after I bought my Panny I, too, discovered this thread. I see RBE on my Panny on high-contrast material. I don't see it at all on hi-def sports, which is why I still have the panel.

What it all seems to indicate is that even fewer folks see the RBE (or whatever we choose to call it) on plasmas than on the single chip DLPs. Oh boy!

Anyway:

1. Does it all mean that SED (if and when it comes out) has a good chance of displaying this artifact?

2. What are the technologies that are "easiest on the eyes" for us hypersensitives and still have good contrast ratio and response time (is it LCOS?)

We are definitely not crazy, nor are we alone. I found several online customer reviews referencing this effect and warning potential plasma buyers. My wife sees it now, too (I asked her to look for it). She says she doesn't notice it if not actively looking for it, though. I've looked at a couple of plasmas in stores but it seems much more difficult to notice, probably due to lighting and source material (or is it possible that some proportion of sets are more likely to exhibit this effect due to manufacturing variances?). There seems to be a big difference for me between 1080i and 720p material; the latter is relatively free of "plrainbows" but the former seems to be the worst offender. It's really bad on some SD material, but on some it's not.

I think I have gotten slightly used to it but there are some scenes and programs where they just start jumping out again. I really hate to take the TV back because the picture is better than anything else. Even the LCoS sets are sort of a risk because I don't know how much the SSE will bother me in the home environment (can see it easily in stores, but it's nowhere near as annoying as the RBE).

I believe I stated my opinion on the matter earlier in the thread, but the least fatiguing displays for me are LCD, LCOS, and 3-chip DLP. Those are not necessarily my displays or preference (I use CRTs), but in terms of only viewer fatigue I prefer these.

I keep saying this, but it's uttrly bizarre how incredibly sensitive I am to so many time-based artifacts, such as DLP rainbows (even seeing some break-up on 3 chip models), CRT flicker, LED light break-up...yet I just never spot these rainbows on any plasmas.

Rich, do you have a plasma at home? In stores it's difficult for me to see them (like I said, lighting and source material). In fact, I couldn't see them at all on the Panasonic I walked past at Sam's Club. But the brand new one sitting in our living room has me running around trying to find the pot of gold!

Makes me wonder if there really is some manufacturing variance that causes this. Or maybe a break-in period?

R Harkness. If you want to see the rainbows and/or trails pop in an old black and white movie and you should be able to see them easily after a while. If you want to really see them, then just dart your eyes back and forth across the screen while watching a black and white movie. If you still can't see them then you never will. I rarely see rainbows. (I do see green trails often while gaming. Very easy to see and anyone Ive shown it to can easily see it without trying) However watching the special features on Cinderella Man where they show the original black and white footage of Baer vs. Brodick. It was like I was getting assaulted by green flashes. After 4 rounds i turned it off because i was getting a headache.

Anyway SED may also have this problem. I notice green trails on my old Sony CRT RPTV, but I have never seen them on my 34" sony XBR.

Also, how many of you that see the rainbows have darting eyes? What I mean is that some people when you look them in the eyes their eyes aren't steady but are constantly shifting or moving about. Ask a friend or someone close to stare at your eyes and ask them if your eyes are steady or they shift around. I have a 50" plasma and sit 7 feet away so I have to naturally move my eyes about the screen and thus sometimes notice rainbows. Do many of you who see rainbows sit really close to the TV? This definetely seems to be a problem with moving your eyes about the screen. If I really concentrate on a DLP and don't move my eyes about (if Im sitting far enough) then I won't see ANY rainbows. As soon as I stop concentrating my eyes may shift a bit every so often and then BAM rainbows.

That makes two of us Rich. I too immediately notice rainbowns on DLPs, but I've never once seen it on any of my plasmas (or any in-store plasmas either).

Three...

I hate rainbow effect on DLP but It's very rare on plasma display. I'm the kind of guy that can see a car wheel pattern at 60mph or fluorescent lightning vibration pulsation...I dont know my eyes or brain is too fast

I already saw this on plasma too, it was a LG plasma with some king of nad dvd player plugged in component I think. It was in a room with Fluorescent lightning( does not help because it flashes every 1/60 seconds ).

maybe it's related to the frequency of the pulsing light from the room and the tv set... but I dont think so because I already saw the same problem in a dark room.

Four solutions to help:

Change the dvd player
Change TV brand ( entry lg model is terrible on that problem)
change component cable to better quality.
Change room light.

that's it.

well that might just mean your not sensitive to time-based artifacts

watch black & white movie or something with a LOT of contrasting blue & yellow & you'll see it

I saw the problem your talking about a long time ago on PBS HD on a pioneer when black and white program was running. Between black and white there were some kind of yellow banding I dont know what is was bizarre but still under the effect of a DLP tv.

I guess I'm lucky since I've never seen a rainbow effect on any HDTV, let alone my HD plasma.

Obviously the vast majority of people don't.

I'm not sure if im seeing the same thing as you guys, here is what I see..

green flashes: if i pause the screen on a dvd where its mostly dark, and a light object on one side, if i dart my eyes around from the bright object to other parts of the screen, I see a green flash where the light object is breifly as my eye moves from it.

so when watching a movie if something catches my attention and i dart my eye around to watch it, it happens to me.

is this what folks are seeing, I was thinking it was just something I had to live with on a big screen, where I see it in a still image.

I've been to Comet today and they were playing a black and white clip on all the latest PDPs. I was looking at the 42 Pioneer and when I moved my eyes to look at the Hitachi, I saw what can only be described as green glow" (similar to rainbow effect on DLPs). I immediately began to notice the same effect on all PDPs on the shop floor but some were yellow mixed with green. Afterwards, I started to notice the same effect in fast sequence videos (in color).



So how many of you are affected by this? I can see rainbow effect on DLP and now this lol. Hopefully I won't see anything on the next display devices (SED and OLED).

Hello,

I have witnessed this same effect. There's actually a thread about the topic already out there, but I can't find it (EDIT: posts have now been moved to this thread). It may have been moved into the Archive or something.

I see it on my NEC 42XR4 occasionally, which is interesting because it uses the same plasma panel as the Pioneer set you first noticed the effect on. When I first got the set, I noticed it quite a lot on high contrast scenes (like movie credits or other black and white stuff).

Now I notice it maybe once per day, and it doesn't bother me. I determined it had a few causes:

1) It's phosphor decay - apparently (according to experts here), green pixels seem to not decay as fast as their brethren, making a yellowish or greenish smear when your eyes track away.
2) If you set contrast and brightness correctly, it mostly goes away. Once I calibrated my set with DVE, 90% of the smearing went away.
3) People who see plasma "smear" seem to always be able to see DLP rainbows. Not everyone who sees DLP rainbows see the smear, but the inverse is true. It's either that we're pickier, or our eyes are better, or something.
4) You get used to it. This was the only real negative I saw on my NEC PQ wise, and within a week I'd gotten used to watching the display and almost never notice it. None of my friends have ever mentioned it.

I really think the main factor in noticing the smearing is paying very close attention to the display, being picky about its PQ. Once you get more casual about watching the set, and make proper display adjustments, it goes away.

Trent

Thanks for the great replay. It would defiantly bother me cos I play games time to time and knowing it's there will dive me insane. It's like finding a dead pixel on an LCD lol.

PS: It is true that the latest PDPs from Samsung no longer suffer from this and the green trail issues?

You're welcome.

This effect is inherent to some degree with any phosphor-based display (CRT, Plasma, probably SED if it ever comes out), so I doubt Samsung has overcome it. However, I've noticed that some brands seem to be less susceptible to the problem.

I still chose plasma because of all the PQ advantages it has over LCDs, despite this little factor.

Trent

I'm not a big fan of LCD either but looks like I have no choice lol

PS: I haven't seen the same effect on any modern CRTs but, I do hate after glow lol

Well, don't jump ship yet - properly calibrate a plasma in a store and see if the problem is still there. Mainly, turn down the brightness and set the contrast to a reasonable level. That's what took care of my issue.

Trent

Add me to the list of those who see the "rainbow effect" on plasma's. I discovered this little treat after I made my purchase. I never noticed them in any show room. At the risk of sounding paranoid I think the video retailers show video that is designed to eliminate this effect!

I was hoping it was just something that would go away after the set was broken in but after reading many of the posts here I guess I'm stuck with it! I see more than just the usual yellow and green flashes I get the whole spectrum of color, an added bonus! Because of this I can only watch for a short time if the all the light are off. Adding a light behind the display helps. I still see the flashes but they aren't as pronounced. Unfortunately the wife likes the lights off for movies. I will look into getting a proper light in the 6500K to help...I'm sure it won't be cheap!

I've calibrated the display using an AVIA DVD and while I highly recommend this to anyone...it's a vast improvement to the "torch mode" settings...the "effect is still present! Some DVDs and TV shows are worse than others. I'll just have to live with it until a better technology comes along. That, and when I can convince the wife into dropping another wad of cash..."h*ll" should be frozen over by then

I'm just adding my voice to the minority that seem to have this problem.

I have noticed the "yellow" flash issue on my Pany TH50PX60U

It showed up tonight a number of times watching "Underworld Evolution" on my SA8300PVR - HDMI @ 1080i

It's such a temporal thing, that sometimes you are not sure what has happened.. you just all of a sudden get a visual "jolt".

Othertimes it's certainly noticable as "yellow"

Especially noticably yellow when the characters were in front of some strong lights in a fairly subdued enviroment, near the begining.

I've seen some "rainbow" effects as well during other programing, and I find watching my new plasma a bit of an eye strain for more than 2 hours.. I'm sitting 10 feet away.. before this I had a 27" CRT

Oh, and that E3 Rainbow 6 Video posted earlier... I see the yellow flashing.

I am not sure if I mentioned this yet (I seem to remember writing about it somewhere) but, yes, I noticed the rainbow effect very quickly after owning my first plasma. I had hypothesized that this effect is due to the fact that the screen is being "pulsed" rather than scanned like a CRT. Basically every RGB subpixel is flashing at 60hz (or 72hz on some plasma's) but since all the pixels blink at the same time your eye can pick out the individual RGB light being emitted. To me it is not a big issue as I really only notice the effect on plasma's when I move my eyes around rapidly (much the same with a CRT, the flicker is really only noticeable when I do the same).

I'd suggest that these problems are not only hardware related, but are likely the result of differences in individual sensitivity in perception. The fact that some posters "see" colors in black & white images proves that it's a major issue for some.

I don't understand the mechanics of it, but visual illusions involving color, shape, and movement are quite well known. See this page for examples:

http://www.ritsumei.ac.jp/~akitaoka/index-e.html

Some display technologies may be worse in this regard, but ultimately it's individual perception that's the main problem.

i have a pioneer 5070 and have yet to see any flashes of yellow...and i almost always watch it in a dark room.

Is that one of the 72Hz Pioneers?

I don't think that makes a difference. I can see it on a pio 5060 which also does 72hz for movies. I think it just depends on your eyes, and some of us are a little unlucky, heh.

are you guys talking about banding??? all HDTVs have banding to some level...it all has to do with both the internal electronics AND how well the original content is encoded.

No we are not talking about banding. And not all displays have banding problems.