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.
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.