Are gray screens better than matte white?

Discussion in 'Archived Threads 2001-2004' started by Arnel Enero, Nov 24, 2002.

  1. Arnel Enero

    Arnel Enero Stunt Coordinator

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    Sorry for this very basic question, but what's the difference?

    I suspect gray screens will require brighter projectors. Will they?

    I'm not exactly an HT newbie, but I've never used front projection. This will be my first time...

    Thanks a lot for the help.
     
  2. Sean M

    Sean M Stunt Coordinator

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    Grey screens are used exclusively with digital front projection. The gain of the screen, how reflective it is, will determine which projectors it can be used with. The Stewart Firehawk has a gain of 1.35 and is suitable for use with projectors 500 - 600 lumens (after calibration) and up. Their Greyhawk, on the other hand, has a gain of .95 and would be better used with high brightness projectors, say in the neighborhood of 1000 lumens and up.

    Screen size will also play a role. The idea is to get a good level of reflected illumination off of the screen. If you're using a high brightness projector on a really large screen, then you made need the additional gain of something like a Firehawk. Stewart aren't the only ones that make Grey Screens now, Da-lite and Vutec also make grey screens that are less expensive that Stewart's. To my knowledge they range in gains from .80 to 1.1 (the 1.0 reference is a piece of Magnesium Carbonate if I'm not mistaken).

    The benefit is improved perceived contrast and black levels as digital projectors are deficient in this area. Another benefit is improved ambient light rejection, especially in the higher gain grey screens as they tend to direct light in a more directional matter, rather than scatter it equally in all directions.
     
  3. Neil Joseph

    Neil Joseph Lead Actor

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    Neil Joseph
    Do you have a projector or are you thinking of getting one soon? Sean's explanation was pretty good. The bottom line is your picture will benefit especially when you get into a room with slight ambient light.
     
  4. Christopher R.

    Christopher R. Auditioning

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    I have used Da-Lite's High-Contrase DA-MAT screen in several theaters and it performs wonderfully. It improves black level nicely. I would only feel safe using gray screens with higher brightness projectors (900 & up).

    Christopher R.
     
  5. Allan Jayne

    Allan Jayne Cinematographer

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    Gray screens are used for projectors (especialy LCD projectors) that don't have really dark blacks. Of course, you need more peak brightness (higher contrast settings) compared with white screens. This latter issue makes gray screens less desirable for CRT projectors where more peak brightness increases phosphor wear (burn-in).
    The gray screen does not help if, when decreasing the brightness and increasing the contrast so highlights equal a white screen's showing, the not so dark maximum black also brightens up.
    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     

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