I have "phosphor trails" on my 34xbr800...do you?

Discussion in 'Archived Threads 2001-2004' started by John_V, Jan 20, 2003.

  1. John_V

    John_V Agent

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    When watching any video source on my 34xbr800 that has a moving bright area surrounded by a dark area I can see noticeable "phosphor trails". Remember the old arcade game Asteroids? Well, it's not as bad as that game, but it's still visible.

    One easy place to spot it is fast-moving credits at the end of a movie or TV show. When the credits have white text on a black background, the text leaves little blurry trails behind it.

    For reference, the set is in "Pro" mode with the picture setting at less than half. SVM is off. I see the trails regardless of picture mode or brightness setting, though. I suspect this is because the set is new...I probably have less than 40 hours logged on the set. Perhaps the phosphor coating needs to "burn-in" a bit? Has anyone else noticed this on their set? I'm hoping it'll go away after time...

    Here's a good way to look for these "trails":

    -Find a movie that has scrolling credits with white text on a black background (just about all do).
    -Roll the credits, then hit PAUSE on your DVD player.
    -What the bottom edge of some letters, then hit play. You should see a faint blurry trail that follows the letters once they start scrolling again.
     
  2. Jesse Skeen

    Jesse Skeen Producer

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    My 40-inch Mitsubishi does this, I have the brightness and contrast tweaked so it's noticable as little as possible though- it's most obvious on video games.
     
  3. Daniel Becker

    Daniel Becker Second Unit

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    I have a 24" Wega and I get phosphor trails on white objects as well. I have my tv pretty well calibrated as well and it's still and issue. Although not as serious. So, I don't know what to tell you. [​IMG]



    Dan.b
     
  4. David Abrams

    David Abrams Stunt Coordinator

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    Greetings,

    These phosphor trails could be a result of the color primaries that each of these displays are using. Now, I have not analyzed the primaries of these sets with a spectrum radiometer, but I will say that the Princeton AF3.0HD has color filtered phosphors that allow for more accurate color, but also cause green lag.

    Basically, in order to achieve better color fidelity the manufacturer has to use phosphors that have a longer decay time; therefore, when something is moving quickly you will see a trail behind it. This happened in the older sets before we realized that we could not accurately reproduce NTSC color space on a direct view.

    What color is your "trail"? Is it green? It could just be the one phosphor (which it usually is) that is causing this.

    Best of Luck,

    David Abrams
    ISF Cailbrationist
     
  5. John_V

    John_V Agent

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    Good question! Well, it certainly doesn't look blue. I'd say it's either white or green, but again the trail disappears so quickly it's hard to tell.

    Perhaps this Sony set uses color-tinted phosphors?

    Thanks for this interesting clue, I've never heard of it before!
     

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