NAME

       ppmflash - brighten a picture to approach white

SYNOPSIS

       ppmflash flashfactor [ppmfile]

DESCRIPTION

       This program is part of Netpbm(1).

       ppmflash  reads  a  PPM  image as input.  It changes the color of each pixel to bring it a
       specified amount closer to white.  It generates a PPM image of the result.

       flashfactor is a real number between 0 and 1, inclusive.  ppmflash increases the intensity
       of  each  RGB  component by the fraction flashfactor of the difference between the current
       value and full intensity.  So if a pixel contains 60% full red, 10%  full  green,  and  no
       blue  and  you  specify  0.5 (half), ppmflash increases the red to 80% (because it was 40%
       from full intensity, so it adds half of 40% to the original 60%), the green  to  55%,  and
       the blue to 50%.

       If  flashfactor is zero, the output is identical to the input.  If flashfactor is one, the
       output is all white.

       pambrighten does  a  more  normal  kind  of  brightening.   pamfunc  does  a  very  simple
       brightening.  Both pambrighten and pamfunc can reduce brightness as well.

       pnmgamma  is  another way people do a similar brightening, though it isn't really intended
       for that.

OPTIONS

       There are no command line options defined specifically for ppmflash, but it recognizes the
       options common to all programs based on libnetpbm (See
        Common Options ⟨index.html#commonoptions⟩ .)

SEE ALSO

       pambrighten(1) pamfunc(1), pnmgamma(1), ppm(1),

AUTHOR

       Copyright (C) 1993 by Frank Neumann

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/ppmflash.html