How Does Raising or Lowering Contrast Level Affect Resolution?

Discussion in 'Archived Threads 2001-2004' started by James Edward, Aug 9, 2002.

  1. James Edward

    James Edward Supporting Actor

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    I think I notice more resolution when lowering my contrast level from 35 to 30. But since there is no definitive way of setting contrast, how do you know if it is too low? All the setup discs walk you through how to tell if it is too high(blooming, line bending), but not how to tell if it is too low.

    DOES lowering contrast level in fact increase resolution? And is there a definitive way to set it? I have a room with well controlled light, so I don't need levels that high... TV is Toshiba 57HX81, DVD is Toshiba SD5700.

    I already like the picture a whole lot, but looking for every little bit I can squeeze out of the set.

    Thanks for any advice.
     
  2. Bill Slack

    Bill Slack Supporting Actor

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    Any amount of blooming should reduce effective resolution. Just find the range that's valid, and set it to a low-ish setting that makes the picture viewable in your enviroment.
     
  3. John-Miles

    John-Miles Screenwriter

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    As far as i know you just have to avoid the blooming range, then whatever you personally perfer.
     
  4. Dave K

    Dave K Extra

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    I saw a very nice setup program a few days ago that should answer your question exactly. It was the THX Optimode setup screens on the recent Speed:SE DVD. They have screens that are different than anything I've seen on Avia or VE.

    First, there is a screen that contains 6 or so different shades of white. You crank your contrast up until you see all six shades. If you go too high or too low, some of the shades will merge together. Second, there are another set for brightness, with 10 shades of black. These two screens worked better for me than the PLUGE and needle tests on other setup DVDs. It will help to have a DVD player that can pass 0 IRE black (your Tosh will, I think), but it's not necessary.
     
  5. jeff lam

    jeff lam Screenwriter

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    The disc(VE) also says to set the level just below the point of blooming. So I would say that's a definitive way of setting contrast.
     
  6. Michael TLV

    Michael TLV THX Video Instructor/Calibrator

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    Greetings

    Actually, there is a more definitive way. You need a light meter to measure the light output of the 100 ire windowbox pattern on either VE or AVIA. Desirable light output is somewhere between 15 to 20 ft-l. This usually translates to contrast settings in the 30 to 35% range on most sets.

    Setting your contrast at a point just below blooming is the wrong way to set proper contrast. When you do it this way, you are effectively driving your TV at 5900 RPM where 6000 RPM is the redline/bloom point.

    I'd like to see how long your car lasts at that constant 5900 rpm.

    Regards
     
  7. James Edward

    James Edward Supporting Actor

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    Jeff- My set does not begin to bloom until contrast is over 50- and from all I've read, it should remain in the 30's to prolong CRT life.
     
  8. JohnnyG

    JohnnyG Screenwriter

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  9. Allan Jayne

    Allan Jayne Cinematographer

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    You can set the contrast as low as you want without losing resolution.
    Use the step gray scale test pattern and adjust brightness and contrast so all the steps are distinguishable.
    The "correct" settings will be different depending on the light level in the room.
    Try to set the contrast way below the blooming point to make the TV last longer.
    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     
  10. JohnnyG

    JohnnyG Screenwriter

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    With the needle pulse pattern, each grey box is half the brightness of the one below it so, focusing on the top two boxes, the 2nd from the top should be half as bright as the one above. Whites should look white.
     
  11. Scott Shanks

    Scott Shanks Second Unit

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    If I set my contrast in the 30 - 35 range, the picture becomes VERY dark and I lose all detail in black fields. My current settings are 40 for contrast and 55 for brightness. I have a Tosh (50HX70). Are these settings acceptable? Thanks.
     

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