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Ppmflash User Manual
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ppmflash
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Updated: 26 January 2003
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Table Of Contents
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NAME
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ppmflash - brighten a picture to approach white
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SYNOPSIS
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ppmflash 
\fIflashfactor\fR
[\fIppmfile\fR]
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DESCRIPTION
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This program is part of Netpbm.
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\fBppmflash\fR 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.
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\fIflashfactor\fR is a real number between 0 and 1, inclusive.
\fBppmflash\fR increases the intensity of each RGB component by the
fraction \fIflashfactor\fR 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), \fBppmflash\fR
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%.
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If \fIflashfactor\fR is zero, the output is identical to the input.
If \fIflashfactor\fR is one, the output is all white.
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\fBppmbrighten\fR does a more normal kind of brightening.
\fBpamfunc\fR does a very simple brightening.  Both
\fBppmbrighten\fR and \fBpamfunc\fR can reduce brightness as well.
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\fBpnmgamma\fR is another way people do a similar brightening, though
it isn't really intended for that.
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SEE ALSO
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ppmbrighten
pamfunc,
pnmgamma,
ppm,
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AUTHOR
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Copyright (C) 1993 by Frank Neumann
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Table Of Contents
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