Latex Beamer ugly transition

To get the section title as well as the subsection dots in the header (see figure) I use the Warsaw theme.

Depending on the color I use, I get very ugly glowing transitions I'd like to remove.

Without the Warsaw theme, there is no such transition. However, in this case I don't get my beloved header.

So I hope you have any suggestion on how to remove these borders.

\documentclass[xcolor=dvipsnames]{beamer}

\usetheme{Warsaw}
\useoutertheme[subsection=false]{smoothbars}
\useinnertheme{default}

\setbeamertemplate{caption}[numbered]
\setbeamertemplate{footline}{}

\setbeamercolor{structure}{fg=ProcessBlue}
\setbeamercolor{frametitle}{fg=white}
\setbeamercolor{frametitle}{bg=ProcessBlue}
\setbeamercolor{block title}{fg=white}
\setbeamercolor{block title}{bg=ProcessBlue}
\setbeamercolor{block body}{fg=black}
\setbeamercolor{block body}{bg=Cyan!10!White}

\usepackage[english]{babel}
\usepackage{graphicx}
\usepackage{multirow}
\usepackage{xcolor}

\begin{document}

\section{Introduction}
\subsection{}

\begin{frame}
\frametitle{frame 1}

\end{frame}

\end{document}

• The problem seem limited to manage secondary colors as cyan or magenta. Not a fix, but a workaround could be supply the right RGB combination insteadof the divpsnames, as \definecolor{Pblue}{RGB}{0,140,204} and \setbeamercolor{frametitle}{bg=Pblue} seem to work in your MWE. – Fran May 13 '14 at 7:44
• I think the problem appears with all dvipsnames, default color names, or svgnames or direct definitions (like Fran suggested) work on my system. – Ignasi May 13 '14 at 8:16
• Using miniframes instead of smoothbars removes the gradient between bars, if that's what you're actually looking for. – Joce May 13 '14 at 9:10

Redefining ProcessBlue as an RGB colour removes the ugly transitions

\documentclass[xcolor=dvipsnames]{beamer}

\usetheme{Warsaw}
\useoutertheme[subsection=false]{smoothbars}

\definecolor{ProcessBlue}{RGB}{0,140,204}
\setbeamercolor{frametitle}{fg=white, bg=ProcessBlue}

\begin{document}

\section{Introduction}
\begin{frame}
\frametitle{frame 1}
\end{frame}

\end{document}