Is it possible to write a script for Adobe Illustrator or some other tool that will read the contents of a number of PDF files and convert all the RGB colours to CMYK?
If so, could somebody please point out some of the steps involved, or where to find more information on this?
On Linux Mint / Ubuntu, I have tried that (from this) using ICC Profiles (Ghostscript 9.18, which don't like "-dUseCIEColor"):
gs -o output.pdf -sDEVICE=pdfwrite -r2400 -dOverrideICC=true -sOutputICCProfile=/usr/share/color/icc/Fogra27L.icm -sColorConversionStrategy=CMYK -dProcessColorModel=/DeviceCMYK -dRenderIntent=3 -dDeviceGrayToK=true input.pdf
It "seems" to work (-r2400 is useful; it's for the resolution, it can be changed or removed).
Maybe adding "-sDefaultRGBProfile=/usr/share/color/icc/colord/sRGB.icc" could be better for the input... I don't know (and I don't know where). Maybe an expert could explain the best way to use.
Thanks. Regards,