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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.3//EN">
<html><head><title>Ppmflash User Manual</title></head>
<body>
<h1>ppmflash</h1>
Updated: 26 January 2003
<br>
<a href="#index">Table Of Contents</a>
<h2>NAME</h2>
ppmflash - brighten a picture to approach white
<h2 id="synopsis">SYNOPSIS</h2>
ppmflash
<i>flashfactor</i>
[<i>ppmfile</i>]
<h2 id="description">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>pambrighten</b> does a more normal kind of brightening.
<b>pamfunc</b> does a very simple brightening. Both
<b>pambrighten</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.
<h2 id="options">OPTIONS</h2>
<p>There are no command line options defined specifically
for <b>ppmflash</b>, but it recognizes the options common to all
programs based on libnetpbm (See <a href="index.html#commonoptions">
Common Options</a>.)
<h2 id="seealso">SEE ALSO</h2>
<a href="pambrighten.html">pambrighten</a>
<a href="pamfunc.html">pamfunc</a>,
<a href="pnmgamma.html">pnmgamma</a>,
<a href="ppm.html">ppm</a>,
<h2 id="author">AUTHOR</h2>
Copyright (C) 1993 by Frank Neumann
<hr>
<h2 id="index">Table Of Contents</h2>
<ul>
<li><a href="#synopsis">SYNOPSIS</a>
<li><a href="#description">DESCRIPTION</a>
<li><a href="#options">OPTIONS</a>
<li><a href="#seealso">SEE ALSO</a>
<li><a href="#author">AUTHOR</a>
</ul>
</body>
</html>
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