[pdftex] color -> grayscale switch?

[siepo at cybercomm.nl]

> Hello.  I have a question.
>
> Is there an easy (or just standard) way with pdflatex to do a
> conversion from color to grayscale when a PDF file is generated?
>
> Ideally I want to come up a scheme where after a document is prepared
> assuming full color, I wish to have an option of generating PDF files
> in grayscale via adding only a few lines to the source or via a
> command switch, if exists (not likely).
>
> Any help would be appreciated.
>
> Taro

My epspdf utility, available from CTAN, offers grayscale
conversion. For converting pdf to grayscale pdf, it would behind
the scenes first convert to Postscript, then prepend a small
Postscript snippet defining crude rgb->grayscale and
cmyk->grayscale mappings, then convert back to pdf. Grayscale conversion
will break down if more advanced color models are used.

If you want to convert a multipage document then you better have pdftops
from the xpdf suite installed because Ghostscript's pdf to ps doesn't
produce nice Postscript.