# Coloring half of a single frame in black

I'm currently working on a presentation using the beamer class and I've stumbled upon a problem that I don't know how to solve. Consider the follwoing MWE:

\documentclass{beamer}

\mode<presentation> {
\setbeamertemplate{footline}{}}

\usepackage{graphicx}
\usepackage{booktabs}
\usepackage[english]{babel}
\usepackage{amssymb, amsthm, mathtools}

\usefonttheme{serif}

\begin{document}
\begin{frame}\frametitle{Useful relations to keep in mind}
\begin{align*}
A&=B+C& U&=\psi(x)\\
G&= AA& C&=\partial^\nu\\
B&=A+B& F&=BB
\end{align*}
\end{frame}
\end{document}


This gives but I'd like it to be

I'm honestly a bit lost at how one could achieve this since I never had to work with "filling" things in Latex with color...

EDIT: Just to make it clear, this should only apply to one frame, all other frames should stay normal!

• Welcome to TeX.SE! – Kurt Mar 18 at 21:28
• Off-topic: you don't need graphicx with beamer – user36296 Mar 18 at 21:32

\documentclass{beamer}
\usepackage{tikz}
\usetikzlibrary{tikzmark}
\mode<presentation> {
\setbeamertemplate{footline}{}}

\usepackage{graphicx}
\usepackage{booktabs}
\usepackage[english]{babel}
\usepackage{amssymb, amsthm, mathtools}

\usefonttheme{serif}

\begin{document}
\begin{frame}[t]
\frametitle{Useful relations to keep in mind}
\begin{align*}
A&=B+C& U&=\psi(x)\\
G&= AA& C&=\partial^\nu\\
B&=A+B& F&=BB\tikzmark{aux}
\end{align*}
\begin{tikzpicture}[overlay,remember picture]
\fill ([yshift=-1ex]pic cs:aux) coordinate (aux) (current page.south west) rectangle
(aux-|current page.east);
\end{tikzpicture}
\end{frame}
\end{document}


You can, of course, move the equations up and it still works.

\documentclass{beamer}
\usepackage{tikz}
\usetikzlibrary{tikzmark}
\mode<presentation> {
\setbeamertemplate{footline}{}}

\usepackage{graphicx}
\usepackage{booktabs}
\usepackage[english]{babel}
\usepackage{amssymb, amsthm, mathtools}

\usefonttheme{serif}

\begin{document}
\begin{frame}[t]
\frametitle{Useful relations to keep in mind}
\vspace*{-3em}
\begin{align*}
A&=B+C& U&=\psi(x)\\
G&= AA& C&=\partial^\nu\\
B&=A+B& F&=BB\tikzmark{aux}
\end{align*}
\begin{tikzpicture}[overlay,remember picture]
\fill ([yshift=-1ex]pic cs:aux) coordinate (aux) (current page.south west) rectangle
(aux-|current page.east);
\end{tikzpicture}
\end{frame}
\end{document}


• First of all, thanks for the answer! This is very close to what I'm looking for... Would it be possible to shift the align environment up a bit (closer to the title) and fill the rest with black? – Marius Jaeger Mar 19 at 10:28
• @MariusJaeger Of course. I added a version that does that. – marmot Mar 19 at 14:10
• Works perfectly! Thank you very much! – Marius Jaeger Mar 19 at 16:14