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How do I tell if I suffer from rainbows?

Discussion in 'TVs' started by Grobnic, Jul 10, 2005.

  1. Grobnic

    Grobnic
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    I'm considering a DLP TV (SAGEM 45HD is the front runner) but I'm concerned about the rainbow affect.

    Can anybody tell me a good way to check if I suffer from this plague?

    I've been into currys & comet and have no problem with the HD stuff the use to demo the set, but as most output will be SD or years yet I'm not confident I'm not a sufferer. I don't want to spend £,000's and find when I get it hope I can see rainbows.

    :lesson:

    a secondary question...

    Is anybody aware of any up-coming improvements to DLP to banish rainbows forever? I've read about 7 bit wheels and new chips but I'm just confused :confused:

    Please excuse dumb questions from a newbee
     
  2. hornydragon

    hornydragon
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    look at lower quality boradcasts in varying ambientlight, ambient light has a big impact on rainbows
     
  3. LV426

    LV426
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    3 chip DLP will banish rainbows. LCDs have been 3 chip since for ever, pretty much. DLPs will catch up. On front projection, today, GBP25k will buy you a totally rainbow-free 3-chip job from SIM2. And beautiful, it is. Prices will fall and 3-chip will get into TVs in due time.

    Any single chip (and therefore, sequential colour) device is bound to generate some sort of temporal artefact, visible by some people. All that faster wheels and/or more segments can ever do, is reduce somewhat, the proportion of people and/or occasions, that the artefact is seen by/on.

    If you aren't affected, go out and enjoy your single-chip DLP. But do be sure, before you part with cash.
     
  4. Mark_a

    Mark_a
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    Try looking off to one side and occasionally whip your eyes back to the picture. Also nod and roll your head a bit, or failing that blow raspberries at the screen. If none of that produces rainbows then you're probably not all that sensitive to it.

    Regards

    Mark
     
  5. mrmoo

    mrmoo
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    The kind of image the little blighters love is a point or edge of light against a dark or black background. Imagine a dark room and a door open a crack with the light on outside. Then flick your eyes quickly across the image. You may see a rainbow from the bright source as you eyes more. For me its worse if the room your in is low light, like your front room. So you may not seem them in a bright showroom, in fact you may not see them for quite a while just standing and watching. I'd recommend asking around and see if anyone lives near you for a demo or a decent showroom with a dark studio.
     
  6. neilmcl

    neilmcl
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    One thing you can do if you decide to take the plunge is to make sure whoever you buy from has a good returns policy, preferably up to 28 days and don't forget to keep all of the original packaging.
     
  7. Grobnic

    Grobnic
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    Thanks for all the replies, I feel a trip to Currys coming on (I may leave some of your advise out or I'll get taken away never to return :devil: ). :thumbsup: :thumbsup:

    Any idea on time scales for 3 chip rear projection TV? projectors are not really an option for me.
     
  8. LV426

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    A couple of years, at a guess. Pure guess, though.

    In the meantime, there are three things you must do to ensure that (as with most people) one-chip DLP is OK for you:

    1: Demo
    2: Demo
    3: Demo.

    .........the TV you intend to buy, in conditions as close as you can get, to those you will experience at home (I doubt you'll achieve this at Curry$). Lighting levels, viewing distance, the TV itself, and (most importantly) the viewer ALL have an impact on this issue. Don't forget to take along any family members etc., who will be sharing your TV.
     
  9. NicolasB

    NicolasB
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    I have a theory that people who can look at a CRT computer monitor refreshed at 60Hz and not perceive any flicker are unlikely to see rainbows, while those who can detect CRT flicker in the corners of the screen even at 75Hz probably will.
     

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