NAME
    ppmdither - ordered dither for color images

SYNOPSIS
    ppmdither [-dim  power]  [-red shades] [-green shades] [-blue shades]
    [ppmfile]

DESCRIPTION
    Reads a portable pixmap as input, and applies dithering to it to reduce
    the number of colors used down to the specified number of shades for
    each primary. The default number of shades is red=5, green=9, blue=5,
    for a total of 225 colors. To convert the image to a binary rgb format
    suitable for color printers, use -red 2 -green 2 -blue 2.

OPTIONS
    -dim power  The size of the dithering matrix. The dithering matrix
     is  a square whose dimension is a power of 2. power is
     that power of 2. The default is 4, for  a 16 by 16
     matrix.

    -red shades  The number of red shades to be used, including black;
     minimum of 2.

    -green shades The number of green shades to be used, including black;
     minimum of 2.

    -blue shades The number of blue shades to be used, including black;
     minimum of 2.

SEE ALSO
   pnmdepth(1),ppmquant(1), ppm(5)

AUTHOR
    Copyright (C) 1991 by Christos Zoulas.