[Openicc] mixed colour space documents

Chris Murphy lists at colorremedies.com
Mon Nov 28 10:07:37 PST 2005

On Nov 27, 2005, at 10:09 AM, Kai-Uwe Behrmann wrote:

> So my conclusion is, the mixed colour space document option is  
> still valid
> but should be renamed. What wold be useful?
> Saving Mixed colour space documents
> For Print:
>    Preserve Numbers | Flatten to Default Cmyk Editing Space | Promt
> For Screen:
>    Flatten to WWW (sRGB) | Flatten to Default RGB Editing Space |  
> Promt
> The first option for the Print setting is similiar to PDF/X-3 the  
> second
> to PDF/X-1a.

I don't follow this. The first option for print specifies conversion  
to CMYK. That is a PDF/X-1a convention. PDF/X-1a is early binding and  
is designed to produce a PDF that is very output device (or  
condition) specific.

The screen example is a normalized workflow where you put everything  
into a single reference color space. It's more like PDF/X-1a than PDF/ 
X-3, except that PDF/X-1a doesn't allow RGB.

PDF/X-3 is also output device/condition specific. If the output  
device is CMYK then you can have /Device CMYK and /Device Gray, as  
well as ICCBased color (RGB, CMYK, Gray, LAB) and also optional spot.  
If the output device is RGB then you can have /Device RGB and /Device  
Gray, as well as ICCBased colors (RGB, CMYK, Gray, LAB) and optional  
spot. The most common form of PDF/X-3 is the CMYK output condition  
specific variety, which contains device dependent (untagged) text and  
other native elements but contains RGB tagged images for later  
separation downstream and is hence late binding. Perhaps it's better  
called later binding, but you get the idea.

Chris Murphy
Color Remedies (TM)
Co-author "Real World Color Management, 2nd Edition"
Published by PeachPit Press (ISBN 0-321-26722-2)

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