DLP Rainbow Progress Thread

Discussion in 'Displays' started by Doug Miller, Mar 21, 2004.

  1. Doug Miller

    Doug Miller Supporting Actor

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    Hey Everybody --

    Wanted to talk about the "Rainbow Phenomenon" on DLP. I've had my Sammy 43" DLP for a little over a week and am one of the guys that can see it. (It makes me think of They Live -- "I've got one that can see , gotta love that movie.)

    Anyway, being an idiot, I was trying to see the rainbow... and well, it worked. At first the rainbows seemed really frequent and jarring. I've noticed that over the last few days, my eyes seem to be adjusting a bit and I'm seeing them less. We watched Harry Potter Sorceror's Stone last night and I only saw them once or twice.

    I'm curious on how everyone else's experience with rainbows is going. How are your eyes adapting, etc? I know the one thing I'm still noticing is that my eyes get fatigued watching it, and I'm curious if this is something that fades. The Doc' has always said that I have better than perfect vision, and I don't want that fading away over a TV [​IMG]. HD looks so damn pretty on the thing that I want to hold onto it, but want to know what the future holds.

    Thanks,
    Doug
     
  2. Jason GT

    Jason GT Second Unit

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    I had some eyestrain initially, though I was sitting pretty close (8-9') from a 50" set.

    As for rainbows, I don't think that there's ever any real "adaptation" to them; some people (apparently) are highly susceptible to rainbows. Personally I see them in classic rainbow situations (high contrast + motion), nowhere else.
     
  3. Michael Osadciw

    Michael Osadciw Screenwriter

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    It's unfortunate I can't watch single-chip DLP too long without getting a serious headache. I really like the colour and depth perception of DLP over other displays. But when I watch it, not only do my eyes get fatigued, but my brain does as well. I don't even have to 'see' colour wheel for that to happen. My brain is picking up something I can't see visually and makes my head feel heavy and hurt...very strange. It's not fun, especially when I have to look at them all day sometimes. Hence, I'm sticking with LCD for now.

    Mike
     
  4. Gabriel_Lam

    Gabriel_Lam Screenwriter

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    Doug,

    One thing you may want to try is using some bias lighting behind the TV (it should not throw any illumination on the screen itself). This tends to help a bit. Use a very dim lamp or something. If that helps, spend a few more bucks and get some D65 bias lighting.
     
  5. Eric Samonte

    Eric Samonte Screenwriter

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    I had an X1 before, great pj but I suddenly saw them. At first I thought it was just a glitch or something, like pixelation then, suddenly it reared its ugly head that I couldn't stand it. I returned it. So a few weeks later I happen to pass by a Samsung DLP. Lo and behold I got a glimpse of rainbows again. While I wasn't getting any headaches and such, I do see them wuite easily that I believe, I'm one the few who are actually susceptible to them. As for "getting used" to rainbows, I don't think I will be. Then again, maybe a 4x wheel might make a world of difference.
     
  6. Scott L

    Scott L Producer

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    Yea have any of you guys seen a DLP with a 4X color wheel? I wonder if the effect disappears completely or we need to go even faster.
     
  7. ChrisWiggles

    ChrisWiggles Producer

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    No, not even the 5x color wheels eliminate rainbows for me.
     
  8. DaveGTP

    DaveGTP Cinematographer

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    I still see rainbows on our X1, but lately it's hard to tell. I think my brain has tuned out a few of the tinier rainbow effects. I have watched very little that is not anime lately (beyond a bit of Babylon 5 and a bit of *cough* some, uh, LOTR movie. Anime shows rainbows only VERY infrequently, as I mostly see them in high-contrast, light on dark, black on white, type scenes.

    I still see a lot of them in very dark movies. I have demo'd a 5x Marantz $12k projector at a HT shop, and didn't see any trace of rainbows. Although, I'm not sure if there was enough contrast for me to be victim to it badly. Samsung RPTVs I can only see them on it if I deliberately try to generate them, and it is very difficult to see.

    I've got an Infocus 4805 on pre-order for upgrade - I'm confident the 4x wheel will get rid of most, or almost all, of the rainbows for me. General comments on the AVSforum rainbow thread and Optoma H30 thread indicate that an upgrade to 4x gets rid of the vast majority of rainbows for a majority 0f people. Some are still victim, though.


    I have a theory that the more of a videogamer you are, the worse the rainbows will likely be. In my small, unscientific sampling of people, so far, the gamers (me and a buddy) see them the worst, followed by the semi-gamers (fiancee, a couple of friends), followed by non-gamers (fiancee's parents). Fiancee's parents, when questioned, have no idea what we are talking about. This is based off comments from those who have seen the X1 in action. Just a theory.
     
  9. Max Leung

    Max Leung Producer

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    I could see rainbows even on an NEC HT1000 (DLP 4x) projector. Plus eyestrain, like looking at a dying fluorescent light.

    I can only see rainbows on a 5x DLP on very high contrast images, such as credits rolling. However, the eyestrain is still there unless the projector brightness is lowered, or on a multi-thousand dollar screen (like a Stewart Greyhawk or Firehawk).

    I blame DLP for making me see rainbows on rear-projection CRT televisions. [​IMG] [​IMG]
     
  10. Guy Kuo

    Guy Kuo Supporting Actor

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    I first learned to see rainbows on my LT150Z, a slow 2x color wheel machine. It was so bad that I was ready to get rid of the machine. After many many hours of watching that projector, I still could see rainbows readily. The difference is that my brain no longer registers them as anything special. On my HT1000, I still can make myself see them, but I simply don't register them as a problem any more. I believe some of us do become accustomed to seeing and ignoring this color separation artifact. There is a skill you gain to see them. Thereafter you can readily make them appear by moving your eyes. With further adaptation, the rainbows effectively disappear from your consciousness.
     
  11. ChrisWiggles

    ChrisWiggles Producer

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    I couldn't help but chuckle at that one! [​IMG] [​IMG]

    If anyone cares to donate a 5x HD2+ projector, I'd be glad to test out whether my susceptibility to rainbows decreases over time [​IMG]

    That and probably you train yourself not to jump your eyes all around the screen, which helps a lot too.

    Dave's gaming theory is an interesting one, I don't think its unreasonable to think that gamers view images differently than non-gamers. I indeed used to game, you get used to picking out all kinds of moving things everywhere on the screen, and discerning and identifying things without looking at what you're trying to see. Might be a factor in seeing rainbows worse. I know that flicker is annoying to me, as well as anyplace with flourescent bulbs. Those drive me nuts, especially since all libraries seem to have them, drives me bonkers while studying.

    It's probably a reaction of not actually "seeing" the rainbows, which is easy enough to do if you dart your eyes around ridiculously on high-contrast stuff, but more when you move your eyes around during normal viewing, I "see" something moving/amiss, in the picture that I would register as some sort of "enemy" if I were gaming. It just kind of distracts me from the entire picture. I've tried gaming once on a DLP projector, and it was impossible. I got a headache almost immediately(it was an old one though), not only because it was too big, but also because it seemed like I kept seeing people that weren't there, probably just rainbow artifacts that I interpret as enemies. I get the same distracting thing with CRTs that are have interlaced flicker, or aren't using a high enough refresh for their phosphor decay time.
     
  12. Anthony_J

    Anthony_J Stunt Coordinator

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    For those of you that can see rainbows or have eyestrain...

    Did you find that it was a gradual realization or was it something that can be immediately spotted when looking at a DLP?

    I'd love to get a DLP, but I hate buying a set and then realizing that I see the rainbows...
     
  13. DaveGTP

    DaveGTP Cinematographer

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    Immediately spotted on high contast scenes. Try Gandalf heading down the stairs with the torch into the Minas Tirith library in FOTR, or any LOTR scenes with swords in the dark (Moria, Weathertop).

    I hear Men in Black is another movie notorious for them as well.

    Anything dark on light or vice versa. Othertimes, I find the rainbows are either not noticeable unless you try, or just nonexistent, for me.
     
  14. Ralph Jenkins

    Ralph Jenkins Stunt Coordinator

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    I'm not sure if it's possible to post a screen shot of the "rainbow" effect. For me, it's just something I sometimes see for an instant if I look away from the screen very quickly.

    The effect is more pronounced in movies with high contrast images. The Godfather is one example.

    There is also an episode of the British TV show Coupling in which the screen is split down the middle for most of the episode. You follow the male characters on one side of the screen and the female characters on the other. Because I had to keep darting my eyes back and forth, I noticed an occasional "rainbow."

    For the most part, though, I usually don't notice it. Movies like The Matrix Revolutions and Monsters, Inc. look very impressive on the DLP.
     
  15. Chester II

    Chester II Stunt Coordinator

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    Anthony dude,

    Don't worry about the rainbow effect so much. On my Plus Piano HE-3200 which has a 4-times color wheel (i think) I notice a flash of rainbow ONCE in a while. It doesn't bother me, doesn't give me headaches, and I could care less. Now when I upgrade my projector within a year or so I'll definately try to buy at a minimum, a 4x machine, but I'm really more concerned with brightness, resolution, etc.

    Good luck dude,

    Chester
     
  16. Max Leung

    Max Leung Producer

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    I had a chance to demo a Sharp Z12000U (5x wheel) during the weekend. It was calibrated and projected onto a 110" Firehawk screen (big bucks). Rainbow was noticeable during the opening scenes of Dark City, but the projector was set to cinema light levels (about 12-15 ft-lamberts), so it wasn't too bothersome. I was sitting at roughly 2x sceenwidth distance.

    I was surprised that I hardly saw any rainbows except in the first minute of Casablanca...probably my brain was learning to ignore them. Matrix Reloaded's first fight scene (Upgrades!), not noticeable except when a street light was in the frame.

    There was a tiny bit of eye strain/tension while watching, but I was able to push it out of my mind. I think the lowered brightness is a big factor. Unfortunately, my girlfriend got a serious headache during Matrix Reloaded, from the huge light behind Agent Smith's head ("I have something for him"). I hope this is just an isolated incident related to too much sun at the zoo. [​IMG]

    I will likely be ordering a Benq 8700+ this week. A Momitsu V880 player will hopefully be delivered to me by the end of the week. I will also be looking for Hoya 72 mm ND (neutral density) filters to dampen the light output, as I will only be projecting onto a 70" screen. Seating distance of 1.5x-1.75x screen widths away - i haven't decided yet.

    I fully expect to ignore rainbow on a 5x projector given time. Eye strain/tension could be alleviated by popping some Gravol, and if my girlfriend still has issues then i will still have my 40" RPTV as backup (behind the screen). :p)
     
  17. Max Leung

    Max Leung Producer

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    I had a chance to demo a Sharp Z12000U (5x wheel) during the weekend. It was calibrated and projected onto a 110" Firehawk screen (big bucks). Rainbow was noticeable during the opening scenes of Dark City, but the projector was set to cinema light levels (about 12-15 ft-lamberts), so it wasn't too bothersome. I was sitting at roughly 2x sceenwidth distance.

    I was surprised that I hardly saw any rainbows except in the first minute of Casablanca...probably my brain was learning to ignore them. Matrix Reloaded's first fight scene (Upgrades!), not noticeable except when a street light was in the frame.

    There was a tiny bit of eye strain/tension while watching, but I was able to push it out of my mind. I think the lowered brightness is a big factor. Unfortunately, my girlfriend got a serious headache during Matrix Reloaded, from the huge light behind Agent Smith's head ("I have something for him"). I hope this is just an isolated incident related to too much sun at the zoo. [​IMG]

    I will likely be ordering a Benq 8700+ this week. A Momitsu V880 player will hopefully be delivered to me by the end of the week. I will also be looking for Hoya 72 mm ND (neutral density) filters to dampen the light output, as I will only be projecting onto a 70" screen. Seating distance of 1.5x-1.75x screen widths away - i haven't decided yet.

    I fully expect to ignore rainbow on a 5x projector given time. Eye strain/tension could be alleviated by popping some Gravol, and if my girlfriend still has issues then i will still have my 40" RPTV as backup (behind the screen). :p)
     
  18. Cameron Yee

    Cameron Yee Executive Producer
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    In my demo of the X1 I saw RBE during movies with high contrast images. During gaming, however, not so much. I mostly played Halo, which does not have a lot of high contrast environments.

    I think if I had purchased the X1 with no knowledge of RBE I could have lived with the discovery. I kind of learned to ignore them, but once in awhile they would seem more obvious. For folks who have never seen it it's actually a strange thing to describe. It's very akin to the afterimage one sees after a camera flash, but it just doesn't persist like one. You see the flash of color and that's it. Despite my awareness of it I still react in a "Did I just see that?" manner becuase it's usually not persisting in my vision.
     
  19. Cameron Yee

    Cameron Yee Executive Producer
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    In my demo of the X1 I saw RBE during movies with high contrast images. During gaming, however, not so much. I mostly played Halo, which does not have a lot of high contrast environments.

    I think if I had purchased the X1 with no knowledge of RBE I could have lived with the discovery. I kind of learned to ignore them, but once in awhile they would seem more obvious. For folks who have never seen it it's actually a strange thing to describe. It's very akin to the afterimage one sees after a camera flash, but it just doesn't persist like one. You see the flash of color and that's it. Despite my awareness of it I still react in a "Did I just see that?" manner becuase it's usually not persisting in my vision.
     

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