White to black transition problem?

Discussion in 'Beginners, General Questions' started by Mason Y, Jan 11, 2004.

  1. Mason Y

    Mason Y Extra

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    Sorry, I'm posting in the newbie area because a: I'm a newbie and b: I don't know what this problem is called so I don't know what to search for.

    When I watch a scene with say a white face, and then the scene changes to a completely dark scene, for a split second I can still see the face of the person in the last frame before it disappears. This also happens when a light colored object moves across a dark background causing a streak while it moves (i searched "streak" but didn't come up with anything like this).

    Does anyone know what this is called and what the cause is? I'm not sure if this is a new problem or I just never noticed it, but it made X2 unwatchable.

    Thanks in advance [​IMG]

    KV32HS500
    Toshiba SD-4900
    Monster component cables
    Marantz 4300 receiver
     
  2. Don__C

    Don__C Extra

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    Have you adjusted your contrast. Sounds like its set skyhigh.
     
  3. Mason Y

    Mason Y Extra

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    Actually I have my contrast set as best I can with DVE. I'll try turning the contrast ("Picture" setting I think) down even more and see what happens. Thanks.
     
  4. ChrisWiggles

    ChrisWiggles Producer

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    This is phosphor decay. Most likely you see a green leftover remnant of bright objects if the screen goes dark very quickly, as in changing scenes, or moving bright objects on a dark background. Phosphors used can have different rates of decay, depending on the set, etc. TVs for consumer use generally have slow phosphor, especially regular TVs, as the refresh rate is very slow, this helps minimize flicker. That's why often you need to have your computer monitor much higher in refresh, because the phosphors used are often much "faster." Green tends to be the slowest, if this is what you are seeing, there isn't much you can do about it. Having a correctly darkened room only seems to make this more visible. I would play around with a little room lighting, and your calibration, and see if you can't reach some sort of middle ground.

    Hope that helps! [​IMG]

    If i can dig up an older thread or two over at AVS, I'll link them. I don't know my chances of finding them though. Try searching around for phosphor decay though, you might dig something up.
     
  5. Mason Y

    Mason Y Extra

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    Thanks Chris. Looks like this is my problem. I'm not sure if it's always been there and just noticed, or if it's a new problem. It just jumps out at me now. If this problem persists I'm gonna kick myself for spending all this $$$ on this set.
     
  6. Jack Briggs

    Jack Briggs Executive Producer

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    Mason, as Chris notes, you're seeing phosphor lag. Your only remedy is to reduce your contrast as much as possible. The HS500 series of HD-capable displays is a good one; you've chosen a very decent set. Just the nature of the technology.
     
  7. Mason Y

    Mason Y Extra

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    Well after doing all I can to fix this, I can say that it's not going to go away. Red push, CUE, and EE are nothing compared to phosphor lag. Simply horrible and makes alot of dark movies unwatchable (X2 and Underworld were a waste of $$$ for me). If this is the way the HS500 is, I'm sorry but I would not call it a "very decent set". If this is the nature of the technology, then I say get a set with another type of technology.

    I'll take red push, CUE, and EE over phosphor lag any day.
     
  8. Allan Jayne

    Allan Jayne Cinematographer

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    The term "comet trail" is often used to describe the ghosting streak of a small bright object moving across the screen due to phosphor decay (phosphor persistence).

    A picture tube with phosphor decay optimized for interlaced TV will show more ghosting with progressive scan. Actually the decay is still not quite right to prevent "seeing scan lines" on an interlaced TV.

    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     

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