NAME
    gamma4scanimage - create a gamma table for scanimage

SYNOPSIS
    gamma4scanimage gamma [shadow [highlight [maxin [maxout]]]]

DESCRIPTION
    The tool gamma4scanimage creates a gamma table in the format expected
    by scanimage. You can define a gamma, a shadow and a highlight value.
    You also can specify the size (maxin) and maximum output value (maxout)
    of the gamma table.

    gamma is a floating point value, neutral value is 1.0, if the value is
    larger than 1.0 then the image gets brighter.

    shadow defines the minmum input value that is necessary to create an
    output value larger than zero.  shadow has to be in the  range
    [0..maxin]. Its default value is 0.

    highlight defines the maximum input value that produces an output value
    smaller than maxout. highlight has to be in the range [0..maxin],
    highlight has to be larger than shadow. Its default value is the same
    as maxin (16383 if not set).

    maxin defines the size of the gamma table. The size depends on the
    scanner/backend.  If the scanner uses 8 bits gamma input then maxin has
    to be set to 255, for 10 bits 1023, for 12 bits 4095,  for 14 bits
    16383. The default is 16383. To find out what value maxin has to be
    call scanimage with a very large gamma table [0]0-[99999]255 then scan-
    image prints an error message with the needed size of the gamma table.

    maxout defines the maximum output value. Take a look at the output of
    scanimage -h to find out what maxout has to be. The default value is
    255.

EXAMPLE
    scanimage --custom-gamma=yes --gamma-table `gamma4scanimage 1.8 0 11500
    16383 255` >image.pnm

SEE ALSO
   scanimage(7)

AUTHOR
    Oliver Rauch

EMAIL-CONTACT
    Oliver.Rauch@Rauch-Domain.DE