How do I add some "texture" to a tikz fill?

Question

I want to create something like this:

By filling a rectangle.

NOTE: Ignore the borders of the image, I just want to give that texture to a tikz rectangle.

Answer 1

A brute-force attempt with pgfplots: there are surely better ways. :-)

The "coarseness" of the texture can be adjusted using the samples key value. For this fine of a texture, LuaLaTeX must be used (dynamic memory allocation). For samples=100 or fewer, any modern engine can be used.

\IfFileExists{luatex85.sty}{%
  \RequirePackage{luatex85}%
}{}
\documentclass{standalone}
\usepackage{pgfplots}
\pgfplotsset{compat=1.12}

\begin{document}
\begin{tikzpicture}
\begin{axis}[
  view={0}{90},
  hide axis=true,
  samples=200,
  colormap={papyrus}{
    cmyk(0cm)=(0.00,0.08,0.24,0); 
    cmyk(1cm)=(0.00,0.08,0.24,0.05)
  },
]
  \addplot3[surf,shader=interp] {rand};
\end{axis}
\end{tikzpicture}
\end{document}