BLACK is too GREEN, green cut at minimum, what to do?

Discussion in 'Archived Threads 2001-2004' started by Jim A. Banville, Jun 8, 2001.

  1. Jim A. Banville

    Jim A. Banville Supporting Actor

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    I have a TV that is OUT of warranty. I don't want to spend the $$$ on a professional calibration. Should I (a)turn up red and blue cuts to compensate, or (b)turn down the green screen voltage knob a "click"?
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    Jim
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    Mancow rocks! www.mancow.com
     
  2. ThomasL

    ThomasL Supporting Actor

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    Jim, you didn't say what type of tv you have but just guessing given what you said, I'd say that your green CRT is probably busted. When you say minimum, do you mean GCUT is at 0?
     
  3. Bob Dycus

    Bob Dycus Extra

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    Your BLACK LEVEL (Brightness) is set too high.
    Once you get brightness set correctly, you will have to tweak GCUT to get your gray scale straightened out.
     
  4. Jim A. Banville

    Jim A. Banville Supporting Actor

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    Okay guys, my green CRT is working fine. Black has a slight green tint (most "normal" people would probably never see it) as set up from the factory. I lowered the green cut to it's minimum (it was already almost there), and there was still just a hint of green, but it is annoying. I went ahead and raised the red and blue cuts slightly and this pretty much eliminated the greenish blacks, but I'm concerned if this is better than slightly lowering the screen voltage knob for the green CRT. Maybe it is being over driven at that point.
    I don't think my brightness setting would have anything to do with a grenish cast to the blacks. Black should stay black no matter where the brightness level is set. By the way, my brightness is set via AVIA calibration DVD.
    thanks
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    Jim
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    Mancow rocks! www.mancow.com
     
  5. ThomasL

    ThomasL Supporting Actor

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    Jim,
    I'd say that probably your grayscale is off at the low end, although it is odd that you lowered GCUT to its minimum and you still saw the problem. What does the Avia color decoder check say? Is your tv pushing green at all? Using the Avia test patterns is the easiest way to check for non-neutral blacks and grays when you're eyeballing it. My 2000 model 27 inch Toshiba exhibits the same behavior (green dark grays in some scenes but no green push according to the color decoder pattern). I can lower GCUT down about 10 notches and the problem goes away it seems but then I'm left with a reddish tint to the low end of the grayscale. My eyes don't seem to notice this though unless I look at an Avia pattern. As you can guess, I still continue to tinker [​IMG] The best way to deal with it, short of opening your set, is to tinker with the BCUT and RCUT values to compensate. I'd definitely recommend doing this while looking at the Avia horizontal grayscale ramp (10 IRE to 100 IRE) or the 20 IRE window pattern. I find those to be the best. Brightness setting will only affect things if your grayscale is off to begin with. For example, if I pick a scene with what I think is a greenish dark gray tint, if I raise the brightness level a good bit, usually the green tint will go away but then of course, the picture looks bad. The real fix is to get the set calibrated with a color analyzer but like you, I don't want to spend the $$$ for the calibration of my lower end set. It would cost as much as the tv did [​IMG]
    good luck,
    --tom
     

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