Ppmflash User Manual(0) Ppmflash User Manual(0)NAMEppmflash - brighten a picture to approach white
SYNOPSISppmflash 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 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.
SEE ALSOppmbrighten(1)pamfunc(1), pnmgamma(1), ppm(1),
AUTHOR
Copyright (C) 1993 by Frank Neumann
netpbm documentation 26 January 2003 Ppmflash User Manual(0)