ppmtopgm(1)

NAME
       ppmtopgm  -  convert  a  portable  pixmap  into a portable
       graymap

SYNOPSIS
       ppmtopgm [ppmfile]

DESCRIPTION
       Reads a portable pixmap as  input.   Produces  a  portable
       graymap  as output.  The quantization formula used is .299
       r + .587 g + .114 b.

       Note that although there is a pgmtoppm program, it is  not
       necessary  for simple conversions from pgm to ppm, because
       any ppm program can read pgm (and pbm  )  files  automagi-
       cally.   pgmtoppm is for colorizing a pgm file.  Also, see
       ppmtorgb3 for a different way of converting color to gray.

QUOTE
       Cold-hearted orb that rules the night
       Removes the colors from our sight
       Red is gray, and yellow white
       But we decide which is right
       And which is a quantization error.

SEE ALSO
       pgmtoppm(1) ppmtorgb3(1) rgb3toppm(1) ppm(5) pgm(5) 

AUTHOR
       Copyright (C) 1989 by Jef Poskanzer.