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%% This work consists of the files colorspace.tex and colorspace.sty.
\documentclass{article}

\title{\textsf{colorspace}\\\large Version 1.0.0}

 \author{Javier Bezos\\\texttt{http://www.tex-tipografia.com}}
   
\raggedright
\parskip=1ex

\date{2015-05-11}

\begin{document}

\maketitle

This package is essentially a reworking of the previous attempts to
provide spot colors and other additional features by Jens Elstner,
Stephan Lehmke and Siep Kroonenberg (with some inspiration from
\textsf{ConTeXt}, too). It requires \textsf{xcolor}, which is loaded
if it has not been before.

It provides a clean user interface, with a single command for
defining a spot color. It seems to work with \textsf{tikz}. Currently
only \textsf{pdftex} and \textsf{luatex} are supported. Mixing spot
colors (with process colors or other spots colors) and other functions
related to the PDF color spaces (like indexed colors) are not yet
suported, but they are\texttt{} under study.

Those docs, like the package itself, are still somewhat tentative, but
the basic behaviour described here will be preserved in future versions.

For transparencies, see \textsf{transparent}, by Heiko Oberdiek.

\section{Spot colors}

Write, for example:
\begin{verbatim}
\definespotcolor{foo}{BarTone 555 GN}{.3,.4,.5,.6}
\end{verbatim}

That's all. Here \verb|foo| is the \LaTeX{} name, as used in
\verb|\color| and the like, \verb|BarTone 555 GN| is the PDF name
(multiple spaces are collapsed into one) as shown by PDF readers, and
the four numbers are the CMYK equivalent. \LaTeX{} knows nothing about
the PDF name, which is just a string to be written to the generated
file, while the PDF knows nothing about the \LaTeX{} name.

You can use tints as usual in \textsf{xcolor}, like:
\begin{verbatim}
\color{foo!60}
\colorlet{foo60}{foo!60}
\end{verbatim}
and even set tints from other tints, but this is the only operation
currently supported. Something like \verb|spot!10!black| (mixing inks)
does not work.

The special PDF names \verb|All| (for all plates) and \verb|None| work
as expected:
\begin{verbatim}
\definespotcolor{registration}{All}{1,1,1,1}
\end{verbatim}

Internally, only CMYK is used, but you can define the equivalent color
with another name space, which is then converted:
\begin{verbatim}
\definespotcolor{foo}{BarTone 555 GN}[rgb]{.5, .4, .3}
\end{verbatim}

To change the color space for a page and the subsequent ones, you can
set something like:
\begin{verbatim}
\pagecolorspace{name1,name2,name3}
\end{verbatim}
(It can be empty.) To return to the default color space, which
contains all the defined spot colors, use \verb|\resetpagecolorspace|.

\section{Overprinting}

This is usually a pre-print task, but by setting it in the document you
will get a better idea of how the colors are actually
overlapped. However, remember the effect produced is device-dependent,
and colorant overprint decisions should be made at output time
(according to the PDF reference).

Very often, it is set for the whole document with the package options
\verb|knockout| (no overprint), and \verb|overprint|. By default, the
overprint mode is 1, but it can be changed with \verb|opm=0|.

Once set the overprint state for the whole document, you can use
something like:
\begin{verbatim}
{\overprintstate{1}text}
\textoverprint[1]{text}
\end{verbatim}
(or \verb|0|, or \verb|no|; default in \verb|\textoverprint| is
\verb|1|, except with the package option \verb|opm=0|).

Since the color stack is used, pdf\TeX{} $\ge$ 1.40 is required.

\end{document}







