#441 error with environment colormixin from package xxcolor

[Elke Schubert]

If package option RGB for package xcolor is set and a value lower than 36 is used in the argument of environment colormixin there will be the error

! Dimension too large.
<recently read=""> \@tempdimb
l.10 \begin{colormixin}{35!green}
I can't work with sizes bigger than about 19 feet.
Continue and I'll use the largest value I can.</recently>

MWE:

\documentclass[RGB]{article}
\usepackage{xxcolor}% loads xcolor too

\makeatletter% from pgfutil-common.tex
\def\pgfutil@namelet#1{\expandafter\pgfutil@@namelet\csname#1\endcsname}
\def\pgfutil@@namelet#1#2{\expandafter\let\expandafter#1\csname#2\endcsname}
\makeatother

\begin{document}
\begin{colormixin}{35!green}
Test
\end{colormixin}
\end{document}

The error goes away if I use 36!green or a larger value for the number.

See also Beamer: clash between RGB and \tableofcontents[currentsection] (German)

There Ulrike Fischer suggests a patch like

\usepackage{xpatch}
\makeatletter
\xpatchcmd\XC@mcolor{\pgfutil@namelet{\string\color@XC@mixtmp}{\string\color@.}}
                {\colorlet{XC@mixtmp}{.}}{}{\fail}
\makeatother

[Stefan Pinnow]

Thank you for reporting. This is fixed now.