How to convert a PDF to grayscale from command line avoiding to be rasterized?

Question

I\'m trying to convert to grayscale this PDF: https://dl.dropboxusercontent.com/u/10351891/page-27.pdf

Ghostscript (v 9.10) with pdfwrite Device fails with a \"Unabl

Answer 1

gs \
   -sDEVICE=pdfwrite \
   -sProcessColorModel=DeviceGray \
   -sColorConversionStrategy=Gray \
   -dOverrideICC \
   -o out.pdf \
   -f page-27.pdf

This command converts your file to grayscale (GS 9.10).