sony kp51hw40 shows green

Discussion in 'Archived Threads 2001-2004' started by Lawrence Ch, Jun 22, 2002.

  1. Lawrence Ch

    Lawrence Ch Auditioning

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    Hi all,

    I just picked up a new sony kp51hw40 rptv and I'm quite astonished with the picture quality. I always thought rptv had substandard picture clarity compared to direct view. Anyways, there is one thing about the picture that bothers me. When I look at the screen and then shift my eyes left or right, I see flashes of green and a little blue on bright colors, especially white. Is this normal for rptvs?
    I performed the flash focus on the sony to self calibrate, but I still see the green. It also happens when you turn your head. Maybe I'm just crazy for noticing these things...I'm not sure what to do. When I'm focusing my eyes on the screen it's fine...nice and clear and no green around the edges or anything. It's only when my eyes start to focus away from the screen.

    Can this be fixed with proper calibration? I haven't picked up the avia disc yet, but I will....Hmm maybe today...

    I still have week or so to return it if it's a defect. I think I'll go to Circuit City and see if I get the same effect there too.

    Thanks in advance for you help fellow home theater enthusiasts!
     
  2. Mark Larson

    Mark Larson Supporting Actor

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    Oooh. I've never seen the DLP rainbow effect, but is this it?
    However, the TV is a CRT? [​IMG]
    I have never seen it with my FPTV.
     
  3. Steve Schaffer

    Steve Schaffer Producer

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    If you don't see it when you look straight at the tv, but only when you shift your eye focus to the side or up and down, this logically cannot be caused by the tv. The tv has no way of knowing you're shifting your eye focus.

    I had a similar phenomenon with an Hitachi analog rptv.

    I usually eat in front of the tv, and with the Hitachi I saw green flashes when my eyes shifted focus from the screen to the plate of food on the coffee table in front of me.

    Others have reported this green flash thing with other makes of rptv, including Toshiba, always associated with movement of the eye's focus from the screen to something to the side or up and down.

    The general consensus in the past has been a theory that the eye's color receptors "decay" at different rates or some such, especially when moving the eye's focus from the screen to other objects.

    Your not the only one who's seen this, but it's not a defect in your set.

    I have the KP57HW40, and though I don't see the green flash on this one I can swear that at times I get a really weird effect.

    Sometimes when I shift my eyes really quickly away from the screen I think I see rows and rows of tiny computer generated numbers on the screen for a fractio of a split second. And no I do not drink or do drugs.
     
  4. Lawrence Ch

    Lawrence Ch Auditioning

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    OK...I went to Circuit City and checked the rptv showroom. Most of them showed some green flashes but it wasn't as obvious as mine at home. Not satisfied with what I was seeing, I checked out the theater room which had one rptv...I think it was a Hitachi. Anyways, this one showed the green flash effect easily. One thing I noticed was that in this theatre room, they had no flourescent lights like the main showroom. They had dimly lit halogens from the ceiling...similar to what I have at home. I wonder if ambient lighting has something to do with all this. But at home, I see the green in pure darkness, dimly lit halogens and natural sunlight. I would say when it's completely dark, the green effect is most prominent.
    Oh well, I guess I'll get used to it and will start to forget about it...I hope [​IMG]
     
  5. Steve Schaffer

    Steve Schaffer Producer

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    Lawrence,
    I think different people have different degrees of sensitivity to this green flash phenomenon. You and I both have seen it on Hitachis, you see it on a KP51HW40 but I don't on the essentially same KP57HW40.


    Last time there was a thread on this, about a year ago, it was started by a gentleman whose wife saw it constantly even when looking straight at a Toshiba rptv, yet he never saw it at all.


    An amusing thing about that Hitachi I saw the green flashes on:

    I once had occasion to make a connection at the back of the set while it was turned on and saw a distinct greenish glow through the ventilation holes in the back of the set. I thought for a while that this meant there was possibly light leakage from the green tube and that this might be the cause of the green flashes.

    I removed the front speaker panel of the set and turned it on to see if I could possibly build a shield of some kind to correct the green tube light leakage.

    To my surprise there was no light leakage from the green crt. Instead I found that the circuit boards that covered the bottom of the set were studded with at least a dozen green glowing LEDs! Why there should be green glowing LEDs on the circuit boards of an rptv where nobody would normally see them is totally beyond my comprehension.
     
  6. Allan Jayne

    Allan Jayne Cinematographer

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    It is possible that the light from the phosphors on the green "gun" decay at a slower rate than from the other guns.
    All CRT phosphors have a decay rate, and it is supposed to be selected (controlled by choosing and mixing) and there is a tradeoff between ghosting and comet trails (longer persistence) and flicker (shorter persistence.)
    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     

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