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I recently ran into this game manual that had the effect of being photocopied, with quasi-transparent pages.

https://www.vidarholen.net/contents/junk/files/TIS-100%20Reference%20Manual.pdf

It seems to have two parts - 1 facing pages seem to "rub off" on one another, and 2 the back of the current page is also semi visible.

Is there a library out there that has a similar visual effect?

If not, how would one approach this problem?

Forkrul Assail
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  • I'm no LaTeX expert, so my method would be 1) create a clean PDF, 2) use imagemagick to convert the PDF to a series of raster images, 3) use imagemagick to composite the raster images with varying levels of opacity, 4) use LaTeX to include the resulting images into a new PDF. It would take a fair amount of experimentation, but could all be automated in a batch file. – James Nov 28 '16 at 19:47

1 Answers1

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I tried the method I from my original comment on a simple two-page document.

Given a LaTeX file "orig.tex" as follows...

\documentclass[12pt]{article}
\usepackage{lipsum}
\title{Sample Document}
\author{Someone}
\begin{document}
\maketitle
\lipsum[1-6]
\end{document}

Executing a DOS batch file calling the Imagemagick convert and composite utilities as follows...

pdflatex orig.tex
convert -density 300 orig.pdf orig.png
convert -flop orig-0.png flop-0.png
convert -flop orig-1.png flop-1.png
composite -blend 80 orig-0.png flop-1.png final-0.png
composite -blend 80 orig-1.png flop-0.png final-1.png
convert final-0.png final-1.png final.pdf

results in a two-page raster PDF "final.pdf", a sample of which is shown in the following image. Changing the "300" density value will change the quality of the raster images. Changing the "80" blend values will change the amount of bleed through of the pages.

To make the facing pages "rub off" on one another would work in the same way. For larger documents, you could set up control loops in your scripting language of choice.

enter image description here

EDIT: Adding some blur to the convert command might make the result more realistic.

convert -flop orig-0.png -blur 0x3 flop-0.png

enter image description here

James
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  • Thanks @James.

    I was interested to know whether this needs to be solved on raster level (your solution), or could somehow be achieved in LaTeX rendering itself, with forward and backward references.

     – Forkrul Assail Dec 05 '16 at 10:13
  • https://www.scanyourpdf.com/ now has the skew (as a service). Remembered this post. – Forkrul Assail May 13 '20 at 14:53