colored caption with tufte-book

Question

I am using the tufte-book class and want to have the captions of the figure enviroment in a different color, especially the word 'figure 1.1'. How can you do that?

Answer 1

You can change the color of the caption using the \setcaptionfont macro provided by Tufte-LaTeX:

\documentclass{tufte-handout}

\usepackage{graphicx}
\usepackage{lipsum}% provides dummy text

% Change the color of the captions (but not sidenotes, margin notes, etc.)
\setcaptionfont{%
  \normalfont\footnotesize
  \color{red}% <-- set color here
}

\begin{document}

\lipsum[1]

\begin{figure}
  \includegraphics[width=\linewidth]{example-image}
  \caption{This is an example figure.}
\end{figure}

\lipsum[2]

\end{document}