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Discussion Starter · #1 ·
Noticed last night that, on my BenQ 8700, rainbows became noticable when I was really tired and moving my eyes away from the screen. Since I could only see them when turning my head rather quickly, it was hardly objectionable.


A search turned up a couple of references to this phenomenon, but I was just wondering how common this is, especially with the newer color wheels, etc.


James
 

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Yeah, I can see them everytime there's a high contrast image if I flick my eyes from one edge of the screen to the other. This sounds worse than it is, but some apparently find this very annoying.
 

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Discussion Starter · #3 ·
I should've mentioned that I too can see them if I try hard enough -- just like you said, darting my eyes across a high contrast image. Of course, darting my eyes rapidly back and forth across the screen is infinitely more annoying than rainbows, so I don't sweat it :)


Interesting how fatigue lowers that tolerance level, though, to make rainbows noticable in normal circumstances (well, as long as turning away from the screen counts as normal).


James
 

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We cant be seeing rainbows. TI and all the manufacturers contracting with them say only 1% of the population can :rolleyes:
 

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Quote:
Originally posted by Tryg
We cant be seeing rainbows. TI and all the manufacturers contracting with them say only 1% of the population can :rolleyes:
I always knew you were special, Tryg. :)


--Darin
 

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Heck, I see rainbows on my CRT. Different mechanism, but once you learn to see color separation during eye movement you can even see the difference in red, green, blue response times of your eyes split up a CRT image!
 

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Guy, think I posted about this in a similar coin when I observed something in my CRT-based RPTV and couldn't really explain it. Initially, I feared it was my vision until I posted it and several others replied their similar observations.
 

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I see CRTBOWS, if I quickly dart my eyes around I see left over images on my computer for just 1 tenth of a second, I also see QUADCARSBOWS if I'm driving and I dart my eyes around in a real quick jerky fashion I see 4 times as many cars and they all seem to be everywhere and I'm afraid I'm going to crash but if I don't dart my eyes I'm just an average boring joe - or dave enjoying my DLP. david
 

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Quote:
Heck, I see rainbows on my CRT. Different mechanism, but once you learn to see color separation during eye movement you can even see the difference in red, green, blue response times of your eyes split up a CRT image!
I can also do this with my CRT RPTV. (I thought I was alone) :)


Quote:
We cant be seeing rainbows. TI and all the manufacturers contracting with them say only 1% of the population can :rolleyes:
I would have to agree with T1 on this. Every guest, co-worker and family member that have watched movies (and Super Bowls) on my DLP have never complained of rainbows. I've even asked some of them. That number is now pushing past 50 people. Some fellow AVS member (guests) can see them though.

Maybe ignorance is bliss. :)


I use to see them. (Of course I tried REAL hard)

Now I can barely see them even if I try.
 

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Quote:
Originally posted by Kysersose


I would have to agree with T1 on this. Every guest, co-worker and family member that have watched movies (and Super Bowls) on my DLP have never complained of rainbows. I've even asked some of them. That number is now pushing past 50 people. Some fellow AVS member (guests) can see them though.

Maybe ignorance is bliss. :)


I use to see them. (Of course I tried REAL hard)

Now I can barely see them even if I try.
I disagree with TI. I think at least 20% are able to see them if they know what to look for. If they mean only 1% of people report rainbows to the manufacturers, I can believe that. I've hardly heard of any one who can't ever see rainbows if they know what they are and how to see them.
 

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Quote:
I disagree with TI. I think at least 20% are able to see them if they know what to look for. If they mean only 1% of people report rainbows to the manufacturers, I can believe that. I've hardly heard of any one who can't ever see rainbows if they know what they are and how to see them.
We'll agree to disagree on this one. I've actually given up trying to get my wife (and some friends) to see what a rainbow is. She still thinks I'm crazy! :) We're now on our second DLP projector.

Yet she could spot pixel structure on a demo of an X1 before she even sat down. :)


I think 20% is way too high but I agree that 1% is too low.

How about 5% ;)
 

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Quote:
Heck, I see rainbows on my CRT. Different mechanism
Interesting. What is the mechanism ? I can vaguely imagine how this might happen on a single CRT system because there is some coupling between spatial and temporal responses due the shadow mask (or aperture grill). But I can't imagine what the mechanism for a 3-CRT projector would be. AFAIK, the traces on each gun are synchronised.


I had better wave my hand in front of my RPTV when I get home (and my wife/kids are not looking :) ) .....


Brent
 

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Yes, I can also see rainbows on my CRT projector on covnergence tet patterns or white text on a black background. I don't have to try too hard on the test patterns or static text, but moving text is harder and requires some unusually rapid eye movement.
 

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I see them now and then, but wow, I watched SWAT last weekend, and I went crazy, they were everywhere. They appeared to be set off by very quick changes in contrast and brightness that this movie seems to have. It takes away from the "being there" feeling for sure. I also see them more when I'm tired. Never saw anything on my crt, though. Of course any image produced by scan lines can be "made" to flicker by fanning your fingers in front of your eyes or something similar.


Bob
 

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Quote:
Originally posted by Guy Kuo
Heck, I see rainbows on my CRT. Different mechanism, but once you learn to see color separation during eye movement you can even see the difference in red, green, blue response times of your eyes split up a CRT image!
yes me too. But not like DLP
 

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I see rainbows also, I agree with Tryg the percent is a lot higher than 1%. Once you see them they never go away. Or maybe I am having flashbacks.

TI knows this, thats why they are trying to make them less noticeable.


Ross
 

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As for percentage we all know statistics are totally unreliable. With the right questions asked you could probably get 70% people to say that they feel safe in their cars and you might also get the same respons from them stating that they fear getting hurt in their cars. It is all about the questionaire!


As for statistics one could easily claim that 95% of all drivers are unable to read roadsigns. No wonder they can't see rainbows!
 

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Discussion Starter · #20 ·
uh-oh... someone just opened up a can o' worms :eek:


There's plenty of 70+ year old technologies still in use. A notable one is the CRT (1897), a technology that one or two pretty good projectors use :rolleyes:


Old != Bad
 
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