NAME
       ppmbrighten - change an images Saturation and Value from an HSV map
SYNOPSIS
       ppmbrighten [-n] [-s <+- saturation>] [-v <+- value>] <ppmfile>
DESCRIPTION
       Reads a portable pixmap as input.  Converts the image from RGB space to
       HSV space and  changes  the  Value  by  <+-  value>  as  a  percentage.
       Likewise with the Saturation.  Doubling the Value would involve
       ppmbrighten -v 100
       to add 100 percent to the Value.
       The  ānā  option  normalizes  the  Value  to  exist  between  0  and  1
       (normalized).
SEE ALSO
       pgmnorm(1), ppm(5)
AUTHOR
       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,
       provided  that the above copyright notice appear in all copies and that
       both that  copyright  notice  and  this  permission  notice  appear  in
       supporting  documentation.   This  software is provided "as is" without
       express or implied warranty.
NOTES
       This program does not change the number of colors.
                                  20 Nov 1990                   ppmbrighten(1)