# Why do I get a sort of strip passing through the frame title when using the dvipsnames option of xcolor in beamer? [duplicate]

Consider the following minimal example:

\documentclass[9pt, xcolor=dvipsnames]{beamer}

\mode<presentation>
{
\usetheme{Frankfurt}
\usecolortheme[named=OliveGreen]{structure}
}

\begin{document}

\begin{frame}
\frametitle{Test title}
\end{frame}

\end{document}


I get surprisingly a sort of strip passing through the frame title when using, for instance, the OliveGreen color. This issue somehow disappears when using a classical color such as blue or green. Any thoughts how this could be fixed?

Thank you!

You can avoid the problem by explicitly selecting a colour model:

\RequirePackage[cmyk,dvipsnames]{xcolor}
\documentclass[9pt]{beamer}
\mode<presentation>
{
\usetheme{Frankfurt}
\usecolortheme[named=OliveGreen]{structure}
}

\begin{document}

\begin{frame}
\frametitle{Test title}
\end{frame}

\end{document}