# info > ppmtopgm

[ppmtopgm(1)](https://www.chedong.com/phpMan.php/man/ppmtopgm/1/markdown)                 General Commands Manual                [ppmtopgm(1)](https://www.chedong.com/phpMan.php/man/ppmtopgm/1/markdown)

## 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 out-
       put.  The output is a "black and white" rendering of the  original  im-
       age, as in a black and white photograph.  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 automatically.  pgmtoppm is for colorizing  a  pgm
       file.   Also,  see ppmtorgb3 for a different way of converting color to
       gray.  And ppmdist generates a grayscale image from a color image,  but
       in  a  way that makes it easy to differentiate the original colors, not
       necessarily a way that looks like a black and white photograph.

## 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)](https://www.chedong.com/phpMan.php/man/pgmtoppm/1/markdown),[ppmtorgb3(1)](https://www.chedong.com/phpMan.php/man/ppmtorgb3/1/markdown),[rgb3toppm(1)](https://www.chedong.com/phpMan.php/man/rgb3toppm/1/markdown),[ppmdist(1)](https://www.chedong.com/phpMan.php/man/ppmdist/1/markdown),[ppm(5)](https://www.chedong.com/phpMan.php/man/ppm/5/markdown),[pgm(5)](https://www.chedong.com/phpMan.php/man/pgm/5/markdown)

## AUTHOR
       Copyright (C) 1989 by Jef Poskanzer.

                                 10 April 2000                     [ppmtopgm(1)](https://www.chedong.com/phpMan.php/man/ppmtopgm/1/markdown)