[texhax] CMYK color v. RGB
will.adams at frycomm.com
Fri Dec 19 14:16:45 CET 2008
On Dec 19, 2008, at 7:12 AM, Niall Mansfield wrote:
> We've just had a book printed, and there are a few color problems:
> more or less consistently, some blues come out looking a little
> too green, and others look purple. The printing company say this is
> probably due to
> the RGB -> CMYK color conversion, and say that we should
> ensure images are in CMYK format rather than RGB before
> they are embedded in the PDF.
> We're using LaTeX, Xfig, GNUplot, Metapost, and all the usual
> tools on Linux. We produce the book as PostScript, and then
> ps2pdf that, to send to the printers.
> I don't think it's possible for us to use CMYK. Is it?
> Does anyone else have experience of similar problems?
Sure it is. You just need to introduce a step where you colour-
separate (and if necessary adjust) all images. You'll also need to
specify any colours for text or vector elements using CMYK (post-
processing them if need be in a pre-press-oriented tool like FreeHand
or Adobe Illustrator).
In theory you could adjust so that they display nicely w/ an RGB
colour profile which has a gamut which your printer can separate to in
a fashion you find acceptable and tag the images w/ that profile and
then the separation would work, but that demands colour-calibrated
> ps: we had advance review copies printed digitally. They were
> fine; only the litho copies were weird. The printers say
> it wasn't a problem with their inking of the litho machine,
> and insofar as I understand what they are talking about, I
> believe them.
The digital machines are usually RGB-oriented and have a wider gamut
than machines which have to print ink in multiple passes.
You should've gotten a colour-separated contract proof which the
printer was able to match on press.
senior graphic designer
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