diff options
| author | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2006-12-25 03:06:05 +0000 |
|---|---|---|
| committer | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2006-12-25 03:06:05 +0000 |
| commit | 1017cbebe5d5edd859e0fddad0a8600f509f4821 (patch) | |
| tree | 78bdf336648566f7a7d55f42837357dea3dd674c /pnmtotiffcmyk.html | |
| parent | 16f2ac126651015a376eba864a3a35f738b0b25a (diff) | |
| download | netpbm-mirror-1017cbebe5d5edd859e0fddad0a8600f509f4821.tar.gz netpbm-mirror-1017cbebe5d5edd859e0fddad0a8600f509f4821.tar.xz netpbm-mirror-1017cbebe5d5edd859e0fddad0a8600f509f4821.zip | |
Place user guide into Subversion repository
git-svn-id: http://svn.code.sf.net/p/netpbm/code/userguide@181 9d0c8265-081b-0410-96cb-a4ca84ce46f8
Diffstat (limited to 'pnmtotiffcmyk.html')
| -rw-r--r-- | pnmtotiffcmyk.html | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/pnmtotiffcmyk.html b/pnmtotiffcmyk.html new file mode 100644 index 00000000..1a7e36c3 --- /dev/null +++ b/pnmtotiffcmyk.html @@ -0,0 +1,224 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2//EN"> +<HTML><HEAD><TITLE>Pnmtotiffcmyk User Manual</TITLE></HEAD> +<BODY> +<H1>pnmtotiffcmyk</H1> +Updated: 07 February 2004 +<BR> +<A HREF="#index">Table Of Contents</A> + +<A NAME="lbAB"> </A> +<H2>NAME</H2> + +pnmtotiffcmyk - convert a Netpbm image into a CMYK encoded TIFF file + +<A NAME="lbAC"> </A> +<H2>SYNOPSIS</H2> + +<B>pnmtotiffcmyk </B> + +[<i>Compargs</i>][<i>Tiffargs</i>][<i>Convargs</i>][<I>pnmfile</I>] + +<p><i>Compargs</i>: +<p> +[<B>-none</B>|<B>-packbits</B>|<B>-lzw</B> + +[<B>-predictor</B> <I>n</I>]] + +<p><i>Tiffargs</i>: +<p> +[<B>-msb2lsb</B>|<B>-lsb2msb</B>] + +[<B>-rowsperstrip</B> <I>n</I>] + +<BR> + +[<B>-lowdotrange</B> <I>n</I>] + +[<B>-highdotrange</B> <I>n</I>] + +<BR> + +[<B>-knormal</B>|<B>-konly</B>|<B>-kremove</B>] + +<p><i>Convargs</i>: +<p> +[[<B>-default</B>][<B>Defargs</B>]|<B>-negative</B>] + +<p><i>Defargs</i>: +<p> +[<B>-theta</B> <I>deg</I>] + +[<B>-gamma</B> <I>n</I>] + +[<B>-gammap</B> <I>-1</I> | <B>-gammap</B> <I>n</I>] + + +<A NAME="lbAD"> </A> +<H2>DESCRIPTION</H2> + +<p>This program is part of <a href="index.html">Netpbm</a>. + +<p><b>pnmtotiffcmyk</b>reads a PNM image as input and produces a CMYK +encoded TIFF file as output. It optionally modifies the color +balance and black level, and modifies removal of CMY from under K. + +<A NAME="lbAE"> </A> +<H2>OPTIONS</H2> + +<p>The order of most options is not important, but options for particular +conversion algorithms must appear after the algorithm is selected +(<B>-default</B>,<B>-negative</B>). If you don't select an algorithm, +<b>pnmtotiffcmyk</b> assumes <B>-default</B> and the appropriate +options (<B>-theta</B>,<B>-gamma</B>,<B>-gammap</B>) can appear +anywhere. + +<h3><B>-none</B>,<B>-packbits</B>,<B>-lzw</B>,<B>-predictor</B></h3> + +<p>Tiff files can be compressed. By default, <b>pnmtotiffcmyk</b> +uses LZW decompression, but (apparently) some readers cannot read +this, so you may want to select a different algorithm +(<B>-none</B>,<B>-packbits</B>). For LZW compression, a +<B>-predictor</B> value of 2 forces horizontal differencing of +scanlines before encoding; a value of 1 forces no differencing. + +<h3><B>-msb2lsb</B>,<B>-lsb2msb</B></h3> + +<p>These options control fill order (default is <B>-msb2lsb</B>). + +<h3><B>-rowsperstrip</B></h3> + +<p>This sets the number of rows in an image strip (data in the Tiff +files generated by this program is stored in strips - each strip is +compressed individually). The default gives a strip size of no more +than 8 kb. + +<h3><B>-lowdotrange</B>,<B>-highdotrange</B></h3> + +<p>These options set tag values that may be useful for printers. + +<h3><B>-knormal</B>,<B>-kremove</B>,<B>-konly</B></h3> + +<p>These options control the calculation of the CMYK ink levels. +They are useful only for testing and debugging the code. + +<P><B>-kremove</B> sets the black (K) levels to zero while leaving the +other ink levels as they would be if the black level were normal. + +<p><B>-konly</B> sets all inks to the normal black value. + +<h3><B>-default</B>,<B>-negative</B></h3> + +<p>These options control what ink levels <b>pnmtotiffcmyk</b> uses to +represent each input color. + +<p><B>-negative</B> selects a simple algorithm that generates a color +negative. None of the following options apply to this algorithm. The +algorithm is included as an example in the source code to help +implementors of other conversions. + +<p><B>-default</B> is not necessary, unless you have to countermand a +<B>-negative</B> on the same command line. + +<p>The default conversion from RGB to CMYK is as follows: The basic +values of the 3 pigments are C = 1-R, M = 1-G, Y = 1-B. From this, +<b>pnmtotiffcmyk</b> chooses a black (K) level which is the minimum of +those three. It then replaces that much of the 3 pigments with the +black. I.e. it substracts K from each of the basic C, M, and Y +values. + +<p>The options below modify this conversion. + +<h3><B>-theta</B> <I>deg</I></h3> + +<p><B>-theta</B> provides a simple correction for any color bias that +may occur in the printed image because, in practice, inks do not +exactly complement the primary colors. It rotates the colors (before +black replacement) by <I>deg</I> degrees in the color wheel. Unless +you are trying to produce unusual effects you will need to use small +values. Try generating three images at -10, 0 (the default) and 10 +degrees and see which has the best color balance. + +<h3><B>-gamma</B> <I>n</I></h3> + +<p><B>-gamma</B> applies a gamma correction to the black (K) value +described above. Specifically, instead of calculating the K value as +min(C,M,Y), <b>pnmtotiffcmyk</b> raises that value (normalised to the +range 0 to 1) to the <I>n</I>th power. In practice, this means that a +value greater than 1 makes the image lighter and a value less than 1 +makes the image darker. The range of allowed values is 0.1 to 10. + +<h3><B>-gammap</B> <I>n</I></h3> + +<p>This option controls the black replacement. + +<p>If you specify <B>-gammap</B>, <b>pnmtotiffcmyk</b> uses the specified +gamma value in computing how much ink to remove from the 3 pigments, but +still uses the regular gamma value (<b>-gamma</b> option) to generate the +actual amount of black ink with which to replace it. + +<p>Values of <i>n</i> from 0.01 to 10 are valid. + +<p>For example, it may be best to only subtract black from the +colored inks in the very darkest regions. In that case, <I>n</I> +should be a large value, such as 5. + +<p>As a special case, if <I>n</I> is -1, <b>pnmtotiffcmyk</b> does not +remove any pigment (but still adds the black ink). This means dark +areas are even darker. Furthermore, when printed, dark areas contain +a lot of ink which can make high contrast areas, like lettering, +appear fuzzy. It's hard to see what the utility of this is. + +<A NAME="lbAG"> </A> +<H2>SEE ALSO</H2> + +<A HREF="pnmtotiff.html">pnmtotiff</A>, +<A HREF="tifftopnm.html">tifftopnm</A>, +<A HREF="pnm.html">pnm</A> + +<A NAME="lbAH"> </A> +<H2>AUTHOR</H2> + +Copyright (c) 1999 Andrew Cooke (Jara Software). Released under the +GPL with no warranty. See source or COPYRIGHT and LICENCE files in +distribution for full details. + +Much of the code uses ideas from other Netpbm programs, written by Jef +Poskanzer (thanks go to him and libtiff maintainer Sam Leffler). A +small section of the code - some of the tiff tag settings - is derived +directly from pnmtotiff, by Jef Poskanzer, which, in turn, +acknowledges Patrick Naughton with the following text: + +<blockquote> +<p>Derived by Jef Poskanzer from ras2tif.c, which is: + +<p>Copyright (c) 1990 by Sun Microsystems, Inc. + +<p>Author: Patrick J. Naughton +<A HREF="mailto:naughton@wind.sun.com">naughton@wind.sun.com</A> + +<p>Permission to use, copy, modify, and distribute this software and +its documentation for any purpose and without fee is hereby granted, +provided that the above copyright notice appear in all copies and that +both that copyright notice and this permission notice appear in +supporting documentation. + +<p>This file is provided AS IS with no warranties of any kind. The +author shall have no liability with respect to the infringement of +copyrights, trade secrets or any patents by this file or any part +thereof. In no event will the author be liable for any lost revenue +or profits or other special, indirect and consequential damages. + +</blockquote> + +<HR> +<A NAME="index"> </A><H2>Index</H2> +<UL> +<LI><A HREF="#lbAB">NAME</A> +<LI><A HREF="#lbAC">SYNOPSIS</A> +<LI><A HREF="#lbAD">DESCRIPTION</A> +<LI><A HREF="#lbAE">OPTIONS</A> +<LI><A HREF="#lbAG">SEE ALSO</A> +<LI><A HREF="#lbAH">AUTHOR</A> +</UL> +</BODY> +</HTML> |