Grayscale help (tw40x81)

Discussion in 'Archived Threads 2001-2004' started by Chris Lambrou, Oct 4, 2001.

  1. Chris Lambrou

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    When eyeballing the grayscale (I'll get it calibrated someday)is it safe to say that it is not perfect until all color temps (warm, medium, cool) look right?
    I seem to have a great picture in meduim, and cool but warm looks too blue (warm should have a red push right?). I've been adjusting the grayscale in medium should I try it in warm?
    Also if you switch from video 1 to 2 etc... the set displays a black image. I've noticed that sometimes this black image is too blue or red and I thought that this is because the grayscale is off but could it also be that the brightness is too high? Even at extreme brightness shouldn't this image be black?
    Thanks for any help
    Chris
     
  2. Eliab

    Eliab Agent

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    Chris,
    How are you altering the greyscale? Are you doing this within the service menu? Also, what test patterns are you using to guide you in your adjustments?
    Brightness and contrast (as well as color, tint, and focus) will all alter greyscale. These controls can also be interactive and thus make pinpointing their optimum locations difficult at times.
    What you’re seeing as a “lack of black” is a clear indicator that your greyscale is not correctly balanced and as a consequence, your entire color palette will be skewed incorrectly towards one shade. This “shade” can also change tone depending on the IRE level of your set making white balance a bit more difficult to adjust.
    Eliab
    ------------------
    Avical
    ISF Certified Calibrations
    www.Avical.com [email protected]
     
  3. Chris Lambrou

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    I'm adjusting the color trimpots located on the front of the tw40x81.
    I have read so many positive responses on the Herman_tlv manuver that I thought I should try it. I recently have read a post were a couple of guys have made it a bit easier by posting what should be the perfect service settings so all you need to do is eyeball the grayscale with the trimpots instead of doing both. I must say I'm getting good results and am only off by a hair (too much green in the 25 ire) could use any advise I could get though.
    I'm using the gray images from the Avia dvd.
     
  4. Eliab

    Eliab Agent

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    Chris,
    I’m assuming that you’re referring to the screen controls found on the focus block. If so, you really shouldn’t use these controls to equalize your greyscale. Instead, you should first go through the entire AVIA and/or Video Essentials procedures to properly calibrate you RPTV at the user level. Next, pop up a staircase pattern and visually inspect what areas of the greyscale need adjusting. Is one end too green, or reddish-brown, or deep blue? If adjustments are necessary (which, will definitely be the case considering that you’ve altered the screen settings) they should be performed within the service menu instead (specifically, the DRVs and CUTs of each of the CRTs).
    Eliab
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    Avical
    ISF Certified Calibrations
    www.Avical.com [email protected]
     
  5. Bill Lucas

    Bill Lucas Supporting Actor

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    Oh my! Do yourself a favor and get a good ISF tech out to properly setup your set. You should NOT be messing with those pots unless you know exactly what you're doing. Not a recommended user adjustment.
    Using the gray bars from AVIA will do you no good. Unless you have a trained professional eye you need a baseline and you have none currently. Good luck.
     
  6. Chris White

    Chris White Second Unit

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    Chris, I don't believe you've gotten an answer to your question yet.
    When eyeballing the grayscale (I'll get it calibrated someday)is it safe to say that it is not perfect until all color temps (warm, medium, cool) look right?
    No, what is perfect for one won't be perfect for the other two.
    I've noticed that sometimes this black image is too blue or red and I thought that this is because the grayscale is off but could it also be that the brightness is too high?
    Yes and yes. [​IMG] One of the things that makes setting grayscale so darned tricky is that virtually everything interacts to impact grayscale.
    I assume you are using the updated http://www.bus.ucf.edu/cwhite/theater/HermanTLV.htm
     
  7. Chris Lambrou

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    Why yes MR White it is your website that I read this on.
    I now have gone 2 days with what I feel is a gray-gray image. The first few nights I'd go to bed thinking I was done only to turn the set on the next day and see the 3 stooges with green faces.
    I'm happy with results, this is a wonderful set but it just kills me that for $200 more than what I paid 12 months ago I could get a 50' this year.
    Thanks for answering my questions...
     

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