What is the raster? (not raster vs. vector)

Discussion in 'Archived Threads 2001-2004' started by David Nilles, Feb 25, 2002.

  1. David Nilles

    David Nilles Auditioning

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    Hello, I am repairing a monitor with the service manual and it says at one point to turn the brightness down until the raster just disappears. It says to make sure it is the raster disappearing and not the image. Can anyone enlighten me on what the raster is that is being referred to? I always thought it *was* the image. This is a direct view computer monitor.

    Thanks,

    David
     
  2. Allan Jayne

    Allan Jayne Cinematographer

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    Raster: The rectangularish array of scan lines as seen on the picture tube face, whether displaying an image, solid color, or snow.
    As you decrease the brightness control setting, when you see the raster disappear will depend on the contrast control setting, the subject matter in the image, and also the lighting level in the room. For this reason calibrating a TV requires test patterns with known brightness levels, back and forth adjustment of brightness and contrast controls and the result will be different whether you watch TV in a sunlit versus somewhat darkened room.
    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     
  3. David Nilles

    David Nilles Auditioning

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    Thanks a lot for the info, Allan! That cleared it up for me.

    David
     

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