\documentclass[25pt,landscape]{foils}
\usepackage[pdftex,dvipsnames]{color}

\usepackage{background}
\usepackage{geometry}
\usepackage[display]{texpower}

\geometry{headsep=3ex,hscale=0.9}


\begin{document}

\foilhead{\macroname{pagecolor\{green\}}}
\pagecolor{green}

\foilhead{\macroname{hpagecolor\{blue\}}}
\hpagecolor{blue}

\foilhead{\macroname{hpagecolor[blue]\{green\}}}
\hpagecolor[blue]{green}

\definecolor{bg1}{named}{SkyBlue}
\definecolor{bg2}{named}{PineGreen}
\foilhead{\macroname{vpagecolor[SkyBlue]\{PineGreen\}}}
\vpagecolor[bg1]{bg2}

\end{document}