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Rainbow Effect

Discussion in 'Displays' started by kumar, May 17, 2006.

  1. kumar

    kumar Well-Known Member

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    Can Rainbow effect be minimized with proper calibration?
    Because what I read in many forums is, not many people have spotted it.
    However considering myself an average joe, first time I saw a Tosh DLP I spotted it. A friend of mine spotted it on a Samsung on the showroom.

    Now both these are factory default settings. Watching Discovery HD, they were showing some AFrican Safari. I was able to feel some head ache/gidiness at times watching the TV. Did not happen in InHD or HDMovie NEt channels.

    Wondering if this is minimizable with proper calibration.
     
  2. ChrisWiggles

    ChrisWiggles Well-Known Member

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    No, not really.
     
  3. Kevin C Brown

    Kevin C Brown Well-Known Member

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    Has to do with the color wheel single chip DLP systems use to generate the 3 colors. I don't see how any kind of calibration could help either. The color wheel is a physical thing. Newer displays use color wheels that rotate faster. That's the only way I've seen it minimized.
     
  4. Mark-P

    Mark-P Well-Known Member

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    The rainbow effect is inherent to the technology. Color wheels with more segments suffer less than color wheels with fewer segments. That being said, individuals tend to perceive it differently. That is, some people (like myself) are more sensitive to it than others. My partner has never seen the rainbow effect on the same projector where I see it quite frequently. Once you get used to it, it's really no big deal.
     
  5. kumar

    kumar Well-Known Member

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    thanks for all your input.
    So when you "get used to it" you don't feel the kinda gidiness I mentioned?
     
  6. Joseph DeMartino

    Joseph DeMartino Well-Known Member

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    Apparently it is a matter of the ability to perceive the rapid color changes. Some people literally cannot see the "rainbow effect". For others it is terribly distracting. Since you seem to be one of the latter, you're probably better off considering a different technology than DLP. Comparable rear projection microdisplays in roughly the same price range as DVD would be LCD RP and Liquid Crystal on Silicon (LCoS). Flat panel technology like LCD (up to about 40") and Plasma (roughly 42" and up) would probably be more expensive. Sony markets their LCoS sets as the SXRD line, which are all 1080p, and JVC offeres their variation of the technology in their HD-ILA sets, which come in 720p and now 1080p models. (I bought my JVC 720p last year. At 56" inches it was the better size match for my room than either the 50" or 61" Sonys and it was a lot cheaper.)

    Some people complain about the "screen door effect" (SDE) with LCD RP, although others say they don't see it unless they're very close to the screen. I was never bothered by the rainbow effect, but have noticed the SDE on some LCD RPs. Any technology choice is a trade-off. None of them are perfect, all have strengths and weaknesses. Because of the SDE, and because I don't see the RBE, my choice came down to DLP and LCoS, which are not prone to it. I was undecided and finally went with LCoS in large part because I got a better discount and better financing on an LCoS set than on the comparable DLP. You may find yourself choosing between LCoS and LCD RP.

    Regards,

    Joe
     
  7. MickeS

    MickeS Well-Known Member

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    I just bought a plasma TV and found out, unfortunately, that there is a rainbow effect there too. I had NEVER heard about this before, and I chose plasma because I had terrible problems with the rainbows on DLP.

    I have found others online who have the same problem with plasma sets. How come this is such a little publicized matter, compared to the rainbows on DLP? Is it just even fewer that see it on plasma sets, does it depend on type of plasma display, have there not been enough plasma displays sold... what is it?

    It looks like I will have to step down in size and buy an LCD instead (to keep it in the same price range as the plasma, comparable LCDs are quite a bit more expensive).

    Beware of this if you're looking to choose plasma instead of DLP.
     
  8. Kevin C Brown

    Kevin C Brown Well-Known Member

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    Yes, ... yes, ... and no.

    [​IMG]

    Big long thread on this over at AVS. Much smaller number of people see this on plasmas than DLPs. (For plasma, supposedly it's due to the different decay rates of the 3 phophor colors.) Some plasmas are worse than others. Many more plasmas have been sold to date than DLPs, by the way. (DLP is still a relatively new technology. Plasma has been around a while.)

    LCD is a viable alternative, but LCD has its own set of issues (the blacks, being the big one). You might try a different plasma manufacturer. Also, if you properly calibrate it (at least with Avia), that does help.
     
  9. ChrisWiggles

    ChrisWiggles Well-Known Member

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    I for one, am somewhat amazed that more people aren't at as bothered by this as DLP. I've explained this in the past, CRTs can also have 'rainbow'-like effects for similar reasons. I think it may be because most people buying plasmas are using them in lit areas or with ambient light which drastically reduces visibility, and further for quite a while the most picky viewers were not generally plasma-users for unrelated reasons, so the folks most apt to be aware of and notice rainbows wouldn't be using plasmas.

    I do know one very picky reviewer who was using a plasma for some time in a light controlled room who is bothered by AFAIK all 1-chip DLPs, but he never mentioned rainbowing on his plasma. I've never asked him specifically about that though, something I'd be curious about.

    I am extremely susceptible t seeing rainbow artifacts, unfortunately. Most viewers will not be bothered at all by things that I might find distracting, so I'm at an extreme. Joe schmoe doesn't know or care about rainbows at all, even with 1-chip DLP.
     
  10. Joseph DeMartino

    Joseph DeMartino Well-Known Member

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    If you aren't married to the idea of a flat panel and can live with a micro-display, LCoS has better blacks than LCD panels or rear projection, no screen door effect and no rainbow effect. And it is priced competitively.

    Regards,

    Joe
     
  11. Kevin C Brown

    Kevin C Brown Well-Known Member

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    Chris- I really think it's because it's a lot more difficult to see. I.e., the spread in colors from (most) DLPs with a color wheel is "slower" than the difference in the 3 color phosphor decay rate for (most) plasmas. Before I got my Panasonic, I tried and tried to see this in a showroom. All the tricks: keep my head steady and waving my fingers in front of my eyes, move my head with my outstretch hand fixed in place, black and white content (supposedly the easiest to see it with: Sin City gets high marks for being "easy" to see this effect with), color content, light and dark ambient, etc. Now that I have my plasma at home, I *think* I saw it once, and I couldn't even repeat it!

    I think I'm lucky. [​IMG] I know people who've returned their plasmas because it distracted them so much.
     

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