<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
<!--Converted with LaTeX2HTML 2008 (1.71)
original version by: Nikos Drakos, CBLU, University of Leeds
* revised and updated by: Marcus Hennecke, Ross Moore, Herb Swan
* with significant contributions from:
Jens Lippmann, Marek Rouchal, Martin Wilck and others -->
<HTML>
<HEAD>
<TITLE>Gamma correction</TITLE>
<META NAME="description" CONTENT="Gamma correction">
<META NAME="keywords" CONTENT="gnuplot">
<META NAME="resource-type" CONTENT="document">
<META NAME="distribution" CONTENT="global">
<META NAME="Generator" CONTENT="LaTeX2HTML v2008">
<META HTTP-EQUIV="Content-Style-Type" CONTENT="text/css">
<LINK REL="STYLESHEET" HREF="gnuplot.css">
<LINK REL="next" HREF="node253.html">
<LINK REL="previous" HREF="node251.html">
<LINK REL="up" HREF="node247.html">
<LINK REL="next" HREF="node253.html">
</HEAD>
<BODY >
<!--Navigation Panel-->
<A NAME="tex2html4832"
HREF="node253.html">
<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A>
<A NAME="tex2html4826"
HREF="node247.html">
<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A>
<A NAME="tex2html4820"
HREF="node251.html">
<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A>
<A NAME="tex2html4828"
HREF="node1.html">
<IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="contents.png"></A>
<A NAME="tex2html4830"
HREF="node467.html">
<IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index" SRC="index.png"></A>
<BR>
<B> Next:</B> <A NAME="tex2html4833"
HREF="node253.html">Postscript</A>
<B> Up:</B> <A NAME="tex2html4827"
HREF="node247.html">Palette</A>
<B> Previous:</B> <A NAME="tex2html4821"
HREF="node251.html">File</A>
<B> <A NAME="tex2html4829"
HREF="node1.html">Contents</A></B>
<B> <A NAME="tex2html4831"
HREF="node467.html">Index</A></B>
<BR>
<BR>
<!--End of Navigation Panel-->
<H3><A NAME="SECTION0402453500000000000000"></A>
<A NAME="commands_set_palette_gamma-correction"></A><A NAME="set_palette_gamma-correction"></A><A NAME="palette_gamma-correction"></A><A NAME="gamma-correction"></A><A NAME="6038"></A>
<BR>
Gamma correction
</H3>
For gray mappings gamma correction can be turned on by <B>set palette gamma
4#4gamma5#5</B>. 4#4gamma5#5 defaults to 1.5 which is quite suitable for most
terminals.
<P>
For color mappings no automatic gamma correction is done by gnuplot. However,
you may easily implement gamma correction. Here is an example for a gray
scale image by use of explicit functions for the red, green and blue component
with slightly different values of gamma
<P>
Example:
<BR>
<PRE>
set palette model RGB
set palette functions gray**0.64, gray**0.67, gray**0.70
</PRE>
<BR>
<P>
To use gamma correction with interpolated gradients specify intermediate
gray values with appropriate colors. Instead of
<P>
<BR>
<PRE>
set palette defined ( 0 0 0 0, 1 1 1 1 )
</PRE>
<BR>
<P>
use e.g.
<P>
<BR>
<PRE>
set palette defined ( 0 0 0 0, 0.5 .73 .73 .73, 1 1 1 1 )
</PRE>
<BR>
<P>
or even more intermediate points until the linear interpolation fits the
<TT>"</TT>gamma corrected<TT>"</TT> interpolation well enough.
<P>
<BR><HR>
<ADDRESS>
2010-08-17
</ADDRESS>
</BODY>
</HTML>
