NAME

       ppmdither - ordered dither for color images

SYNOPSIS

       ppmdither

       [-dim=power]

       [-red=n]

       [-green=n]

       [-blue=n]

       [netpbmfile]

       All  options  can be abbreviated to their shortest unique prefix.  You may use two hyphens instead of one
       to designate an option.  You may use either white space or an equals sign between an option name and  its
       value.

DESCRIPTION

       This program is part of Netpbm(1).

       ppmdither  reads a Netpbm image as input, and applies dithering to it to reduce the number of colors used
       down to the specified number of shades for each primary.  It produces a PPM image as output.

       The default number of shades is 5 red, 9 green, and 5 blue, for a total of 225 colors.   To  convert  the
       image to a binary rgb format suitable for primitive color printers, use -red=2 -green=2 -blue=2.

       You can do another kind of dither -- Floyd-Steinberg -- with pnmquant or pnmremap.

OPTIONS

       In  addition  to  the options common to all programs based on libnetpbm (most notably -quiet, see  Common
       Options ), ppmdither recognizes the following command line 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=n The number of red shades to be used, including black; minimum of 2.

              Default is 5.

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

              Default is 9.

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

              Default is 5.

SEE ALSO

       pamditherbw(1), pamdepth(1), pnmquant(1), pnmremap(1), ppm(1)

AUTHOR

       Copyright (C) 1991 by Christos Zoulas.

DOCUMENT SOURCE

       This manual page was generated by the Netpbm tool 'makeman' from HTML source.  The  master  documentation
       is at

              http://netpbm.sourceforge.net/doc/ppmdither.html

netpbm documentation                            16 December 2009                        Ppmdither User Manual(1)