man > ppmflash(1)

Ppmflash User Manual(1)                General Commands Manual               Ppmflash User Manual(1)

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 speci‐
       fied 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  inten‐
       sity, 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 .)


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

netpbm documentation                       26 January 2003                   Ppmflash User Manual(1)