[scribus] Two color management questions

[Hadmut Danisch]

Am 19.01.2012 22:49, schrieb Patrick Noffke:
> PDF/X-3 specifically allows the images to be saved in the file as RGB, as
> long as they have a profile associated with them.  The profile(s) for RGB
> images define what L*a*b* color you want for each RGB value for that image.
>
> Then the output intent tells how to convert from L*a*b* to CMYK. 

So the rendering intent is stored in the PDF/X-3 file?

I believed the intent is used only locally to convert the given into the
wanted colormodel (i.e. some RGB to some CMYK)




>
> Your printer has said Fogra27L should be your output intent.  Did they give
> you an ICC profile?  
No. They just said they use what all printing service providers use, "4C
Euroskala". On their website they say they're using Fogra27L.


> Any printer that accepts PDF/X-3 should convert the RGB images to CMYK
> (possibly during their RIP) using first the image profiles to convert to
> L*a*b*, and next the output intent profile to convert to CMYK.  This should
> be supported by their RIP software or some step in their process.  They may
> add a further step that does ink optimization (i.e. GCR), which is supposed
> to leave the color (L*a*b* value) alone.

That would make sense.

But where in that process does the rendering intent (perceptual,...)
play it's role? Do the image profiles depend on it?





regards
Hadmut