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<H1>ppmflash</H1>
Updated: 26 January 2003
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<A HREF="#index">Table Of Contents</A>
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<H2>NAME</H2>
ppmflash - brighten a picture to approach white
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<H2>SYNOPSIS</H2>
ppmflash
<I>flashfactor</I>
[<I>ppmfile</I>]
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<H2>DESCRIPTION</H2>
<p>This program is part of <a href="index.html">Netpbm</a>.
<p><b>ppmflash</b> 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.
<p><i>flashfactor</i> is a real number between 0 and 1, inclusive.
<b>ppmflash</b> increases the intensity of each RGB component by the
fraction <i>flashfactor</i> 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), <b>ppmflash</b>
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%.
<p>If <i>flashfactor</i> is zero, the output is identical to the input.
If <i>flashfactor</i> is one, the output is all white.
<p><b>ppmbrighten</b> does a more normal kind of brightening.
<b>pamfunc</b> does a very simple brightening. Both
<b>ppmbrighten</b> and <b>pamfunc</b> can reduce brightness as well.
<p><b>pnmgamma</b> is another way people do a similar brightening, though
it isn't really intended for that.
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<H2>SEE ALSO</H2>
<A HREF="ppmbrighten.html">ppmbrighten</A>
<A HREF="pamfunc.html">pamfunc</A>,
<A HREF="pnmgamma.html">pnmgamma</A>,
<A HREF="ppm.html">ppm</A>,
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<H2>AUTHOR</H2>
Copyright (C) 1993 by Frank Neumann
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<H2>Table Of Contents</H2>
<UL>
<LI><A HREF="#lbAB">NAME</A>
<LI><A HREF="#lbAC">SYNOPSIS</A>
<LI><A HREF="#lbAD">DESCRIPTION</A>
<LI><A HREF="#lbAE">SEE ALSO</A>
<LI><A HREF="#lbAF">AUTHOR</A>
</UL>
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