CMYK/RGB conversion

[Christiane Crety (CC)]

Thanks Richard - I was afraid that would be the case!

I guess I was just hoping there would be some magic Distiller setting
that could bring back my CMYK ;-) At least I would think that an
"absolute" color like black should be easily converted to RGB and back
to CMYK. When I select "Leave color unchanged" in the Distiller the RGB
color is R=0%, G=0%, B=0% as it should be - so it is the conversion back
to CMYK that I can't get right...

What I don't understand is how other people cope with this? There must
be at least a million people out there who need to deliver "all CMYK"
documents to their print shop?

Best regards,

Christiane




-----Original Message-----
From: Combs, Richard [mailto:richard.combs at Polycom.com] 
Sent: 7. november 2006 19:16
To: Christiane Crety (CC); Framers at frameusers.com
Subject: RE: CMYK/RGB conversion 

Christiane Crety wrote:
 
> I know there are also tools that can convert to CMYK after 
> creating the pdf file, but I would really prefer it if the 
> Distiller could take care of it...
> 
> Does anyone know how to keep the original CMYK values in the 
> pdf output? I'm pulling my hair out....

I'm not an expert, but I haven't seen any other responses, so here's my
(limited) understanding of this issue: 

You can't stay in the CMYK color space on a Windows machine because FM
doesn't have its own print engine -- it uses the Windows GDI (even to
"print" to Distiller). That means everything except EPS graphics (and
maybe imported PDFs) is converted to RGB first. 

The conversion from RGB back to CMYK is of necessity not perfect --
although the values you cite strike me as unusually far off. Maybe
someone knows what settings will get you closer. 

But I suspect you really need those post-processing tools you'd prefer
to avoid. :-}

HTH!
Richard


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Richard G. Combs
Senior Technical Writer
Polycom, Inc.
richardDOTcombs AT polycomDOTcom
303-223-5111
------
rgcombs AT gmailDOTcom
303-777-0436
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