%% The LaTeX Graphics Companion, 2ed (first printing May 2007)

%%
%% The LaTeX Graphics Companion, 2ed (first printing May 2007)
%%
%% Example 11-2-16 on page 731.
%%
%% Copyright (C) 2007 Michel Goossens, Frank Mittelbach, Denis Roegel, Sebastian Rahtz, Herbert Vo\ss
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3
%% of this license or (at your option) any later version.
%%
%% See http://www.latex-project.org/lppl.txt for details.
%%

\documentclass{ttctexagray}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{111.83385pt}
\setlength\parindent{0pt}
\StartShownPreambleCommands
\usepackage{xcolor}
\colorlet{test}{yellow!90} \colorlet{anti}{-test}
\StopShownPreambleCommands
\begin{document}
\newcommand\blob[1]{\fbox{\color{#1}\rule{1.5cm}{5mm}}}
\blob{test} \blob{anti} \\
\blob{test!50!anti} \blob{gray} \\
\blob{rgb,1:test,1;anti,1}
\end{document}