Ppmflash User Manual(0)                                Ppmflash User Manual(0)


       ppmflash - brighten a picture to approach white


       ppmflash flashfactor [ppmfile]


       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 flashfac-
       tor 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.

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

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


       ppmbrighten(1) pamfunc(1), pnmgamma(1), ppm(1),


       Copyright (C) 1993 by Frank Neumann

netpbm documentation            26 January 2003        Ppmflash User Manual(0)

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