[pdftex] Changing colour of included PDFs

[Dario Teixeira]

Hi,

Here's one curious problem: I wanted to change the colour of a PDF image
included via \includegraphics.  My first assumption was that something
like \textcolor[named]{Red}{\includegraphics{...}} would be beyond xcolor's
capabilities.  However, much to my surprise, it "sort of" works for some
PDF files, though not for all.

I say "sort of" because even though the images are rendered in red by xpdf
or Adobe Reader, the colour postscript printer I am using prints them in
black!  (So much for what you see is what you print).

To make your life easier, I made a simple example which illustrates the
problem.  You can find it here: http://www.dse.nl/~dario/misc/pdfcolor.tgz

Anyway, my question is: what makes some of these PDF files colour-changeable
while the others are colour-invariant?  And is there a way to make all PDFs
colour-changeable, even for printing?

Thanks for your help!
Kind regards,
Dario Teixeira

P.S. Versions of the programmes involved:

	xfig: 3.2.5_alpha5
	pdftex: 3.141592-1.21a-2.2
	Adobe Reader: 7.0.0 (Linux version)
	xpdf: 3.01