PNMGAMMA

NAME

      pnmgamma - perform gamma correction on a portable anymap

SYNOPSIS

      pnmgamma value [pnmfile]
      pnmgamma redvalue greenvalue bluevalue [pnmfile]

DESCRIPTION

      Reads a portable anymap as input.  Performs gamma correction, and
      produces a portable anymap as output.
      The arguments specify what gamma value(s) to use.  A value of 1.0
      leaves the image alone, less than one darkens it, and greater than one
      lightens it.

DEMONSTRATION

      Let a.pnm be a portable anymap.
      The following command will lighten it:
	pnmmerge pnmgamma 2 a.pnm >alighter.pnm

BEFORE

AFTER

gamma=2

gamma=0.5

SEE ALSO

      pnm(5)

AUTHOR

      Copyright (C) 1991 by Bill Davidson and Jef Poskanzer.