calibration explained?

Discussion in 'Displays' started by adi.soffer, Mar 14, 2005.

  1. adi.soffer

    adi.soffer Auditioning

    Joined:
    Mar 13, 2005
    Messages:
    3
    Likes Received:
    0
    Trophy Points:
    0
    Hi Guys

    I've been looking around for some complete explanation on how to calibrate my plasma (NEC 42"), and most people point to using AVIA dvd or else Video Essentials.
    It seems to me that both are out of date, and I've used Video Essentials but am not fully satisfied.
    I've read a few articles referring to "Grey" levels, but than again, what do I use to calibrate?

    To sum all this up:How can I calibrate my plasma most professionally?
    (and since I'm from Israel, I have no professional calibrators...)

    Thanks
    [​IMG]
     
  2. Jeff Gatie

    Jeff Gatie Lead Actor

    Joined:
    Aug 19, 2002
    Messages:
    6,531
    Likes Received:
    15
    Trophy Points:
    0


    Grey scale can only be calibrated using special equipment.
     
  3. Michael TLV

    Michael TLV THX Video Instructor/Calibrator

    Joined:
    Mar 16, 2000
    Messages:
    2,909
    Likes Received:
    1
    Trophy Points:
    0
    Location:
    Calgary, Alberta
    Real Name:
    Michael Chen
    Greetings

    The tv system works in two components ... the b/w realm and the colour realm.

    Grayscale calibration works to make the black and white information as neutral as possible ... not blue tinted or green tinted or red tinted. Black black and white white and gray gray ...

    The TV takes the b/w signal and then overlays colour on it ... thus achieving our colour tv system. When the b/w information is not neutral ... then the entire colour palette is then skewed in one direction or another ...

    Grayscale calibration requires proper instrumentation ... a colour analyzer ($2000 US or more)for example ... or an optical comparator ($900 US).

    Without these items, you can only do grayscale by "eyeballing" it. YOu take one of the pluge patterns with the 4 to 5 gray boxes and you change the mix of r/g/b on the bright end and the dark end to get something that looks neutral b/w to you. Most humans will end up with something slightly blue tinted, but it will look b/w to you and that is what counts with the eyeball.

    While the disc themselves are not as new ... the patterns on the disc are still as valid today as they were when they first came out. The TV system is the TV system and the rules did not change. A hammer is still a hammer whether new or 5 years old.

    Regards
     
  4. Allan Jayne

    Allan Jayne Cinematographer

    Joined:
    Nov 1, 1998
    Messages:
    2,404
    Likes Received:
    0
    Trophy Points:
    0
    You want black to be as dark as possible without losing shadow detail. There is a test pattern with several steps of gray scale, you just need to make sure all the steps are distinguishable. Video Essentials even has a gray scale with three tints, an orangish tint, neutral in the middle, and a bluish tint. You can use this to help get the neutral gray you want.

    For plasma (and also CRT direct view or projection) you want to go easy on the contrast which determines the maximum brightness. As with most of the calibration adjustments, you can use personal preference but lower contrast prolongs the life of the phosphors and power supply components and therefore the life of the TV set. A technically correct calibration requires a light meter but for home use you really don't need to go that far with effort and expense.

    (Anyone come up with a usable rule of thumb for adjusting contrast with a photographer's light meter held about a half inch from the screen in front of a white patch? Even though the correct value in foot lamberts might be higher than the level suggested for minimizing phosphor wear?)

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

    ChrisWiggles Producer

    Joined:
    Aug 19, 2002
    Messages:
    4,791
    Likes Received:
    1
    Trophy Points:
    0
  6. adi.soffer

    adi.soffer Auditioning

    Joined:
    Mar 13, 2005
    Messages:
    3
    Likes Received:
    0
    Trophy Points:
    0
    First - Thanks.
    But I think I'm trying to find a more accurate way of calibrating, and what I begin to understand is that I need a Pro technician...
    What about Avia Pro which is sometimes mentioned? Do I need additional light-meters to use with it?
     
  7. ChrisWiggles

    ChrisWiggles Producer

    Joined:
    Aug 19, 2002
    Messages:
    4,791
    Likes Received:
    1
    Trophy Points:
    0
    Avia Pro is a suite of test patterns designed for the advanced enthusiast (read, crazy fanatic!) or professional. It basically has tons more patterns and variations which can be helpful in advanced situations. You, of course, will still need whatever ancillary equipment, like light meters, colorimtry equip, etc, just as with the consumer DVDs.

    You should start by doing the basic calibration using DVE or Avia. Grayscale you can use the same discs for, but you need colorimetry equipment of course.
     
  8. adi.soffer

    adi.soffer Auditioning

    Joined:
    Mar 13, 2005
    Messages:
    3
    Likes Received:
    0
    Trophy Points:
    0
    Since I own Video Essentials and have used it, my question is this - Is there a real difference between VE and DVE, and if I'm buying, should I get Avia...?
     

Share This Page