How to convert color eps to grayscale

That turned out more complicated that it seems. The default ways didn't seem to work for me, because the eps was produced by Maple (so there is a bitmap graphics inside).

Here is what it worked for my figure.eps:

$epstopdf figure.eps
$gs  -sOutputFile=output.pdf  -sDEVICE=pdfwrite  -sColorConversionStrategy=Gray  -dProcessColorModel=/DeviceGray  -dCompatibilityLevel=1.4  -dNOPAUSE  -dBATCH  figure.pdf
$ pdftops -eps output.pdf

This can be done easily to a script like this:

#!/bin/bash
epstopdf $@ -o output_eps.pdf
gs -sOutputFile=output.pdf -sDEVICE=pdfwrite -sColorConversionStrategy=Gray -dProcessColorModel=/DeviceGray -dCompatibiltyLevel=1.4 -dNOPAUSE -dBATCH output_eps.pdf
pdftops -eps output.pdf

Save it as epstograyscale.sh
$sudo chmod +x  epstograyscale.sh
$sh epstograyscale.sh figure.eps

It worked on my PC.