xcolor=x11names statt xcolor=dvipsnames
\usepackage{/usr/share/texmf/tex/latex/beamer/themes/color/BeamerColor} auskommentiert
\usecolortheme[named=firebrick]{structure}
und
\setbeamercolor{background canvas}{bg=seashell}
gesetzt, mal Firebrick und mal firebrick, mal seashell, mal Seashell
und bekomme jedesmal die Meldung:
/usr/share/texmf/tex/latex/beamer/themes/color/beamercolorthemestructure.sty:20:Package xcolor Error: Undefined color 'firebrick' \ProcessOptionsBeamer
gleichzeitig wird in einem Tabulator die Datei 'beamercolorthemestructure.sty' geöffnet, welche bei mir folgenden Inhalt aufweist:
% Copyright 2007 by Till Tantau
%
% This file may be distributed and/or modified
%
% 1. under the LaTeX Project Public License and/or
% 2. under the GNU Public License.
%
% See the file doc/licenses/LICENSE for more details.
\ProvidesPackageRCS $Header: /cvsroot/latex-beamer/latex-beamer/themes/color/beamercolorthemestructure.sty,v 1.4 2007/01/28 20:48:24 tantau Exp $
\DeclareOptionBeamer{gray}{\definecolor{beamer@structure@color}{gray}{#1}}
\DeclareOptionBeamer{rgb}{\definecolor{beamer@structure@color}{rgb}{#1}}
\DeclareOptionBeamer{RGB}{\definecolor{beamer@structure@color}{RGB}{#1}}
\DeclareOptionBeamer{cmyk}{\definecolor{beamer@structure@color}{cmyk}{#1}}
\DeclareOptionBeamer{cmy}{\definecolor{beamer@structure@color}{cmy}{#1}}
\DeclareOptionBeamer{named}{\definecolor{beamer@structure@color}{named}{#1}}
\DeclareOptionBeamer{hsb}{\definecolor{beamer@structure@color}{hsb}{#1}}
\ProcessOptionsBeamer
\setbeamercolor{structure}{fg=beamer@structure@color}
best regards,
hans1967

