ppmbrighten [-n] [-s <+- saturation>] [-v <+- value>] <ppmfile>

       Reads a portable pixmap as input.  Converts the image from RGB space to
       HSV space and changes the Value by <+- value> as a  percentage.   Like-
       wise with the Saturation.  Doubling the Value would involve

       ppmbrighten -v 100

       to add 100 percent to the Value.

       The  'n'  option normalizes the Value to exist between 0 and 1 (normal-

       pgmnorm(1), ppm(5)

       Copyright (C) 1990 by Brian Moffet Copyright (C) 1989 by Jef Poskanzer.

       Permission to use, copy, modify, and distribute this software  and  its
       documentation  for  any purpose and without fee is hereby granted, pro-
       vided that the above copyright notice appear in  all  copies  and  that
       both  that  copyright  notice and this permission notice appear in sup-
       porting documentation.  This  software  is  provided  "as  is"  without
       express or implied warranty.

       This program does not change the number of colors.

                                  20 Nov 1990                   ppmbrighten(1)
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