Frankly, for photographic images, I don't understand Mr. Blatner's reluctance to preserve profiles, and I think the default settings to ignore them are pretty dumb. It just sets you up for never having a good color match.
Sure, CMYK-to-CMYK conversions are less than ideal but it will probably get you a better match than not doing it, and the biggest argument against them -- conversion of 100% K to a four-color mix -- is essentially irrelevant with images.
Well I wanted to give some reading material until Rob Day makes an appearance.
I'd try to give my explanation, but what works well in my thoughts does not usually translate to written word very well, especially on this subject.
If your InDesign document's CMYK Color Management policy is set to Off or Preserve Numbers (Ignore Linked Profiles) then the emebedded profiles of any placed files will be ignored and the document CMYK profile will be assigned instead.
The color management policy is save with the document when it is created, so changing your Color Settings policy won't change the document's policy. To change the document's policy choose the policy you want with the document closed, check Ask When Opening, then reopen the document. In that case you be given the option to change the policy.
and I think the default settings to ignore them are pretty dumb.
But the policy also covers PDFs, AI, and ID placed files, which could easily have large areas of colors that won't do well with a CMYK-to-CMYK conversion.
It's easy to come up with scenerios where either policy is a problem. It wouldn't make much sense to convert Coated Fogra to Coated Gracol because their appearance is almost identical, but it would be really problematic to leave Coated Fogra unchanged in a US Newsprint document.
my problem is that i receive Indesign docs from external suppliers that use images with different ICC profiles (both RGB and CMYK) both for gravure print and web offset print. I have to print them in gravure so i MUST convert tha images optimized for web offset as the inks are completely different. There are no problems of course with RGB files, but i can't afford to relink every single CMYK image setting the colour options during the import (also lot of them are as eps, so there is not the colour option). I can't understand why RGB profiles are keeping and CMYK not.
I can't understand why RGB profiles are keeping and CMYK not.
You have to change the document's policy to Preserve Embedded or Convert (converts native colors). So set your Color Settings to something like this
Then when you open a document with a conflicting policy you'll get the opportunity to change the policy
The way I see it, is that the only time I'd be likely to have CMYK raster images would be when I wanted to work with particular channels, in which case I'd want those channels preserved. Most of my vector graphics have black elements I want to keep on the black plate, and I'll have different versions for different outputs. I guess it's different if you're working with supplied files from people who still think they have to convert all their raster images to CMYK.
it works, but i should set it as default a si have hundred of docs and i use an automatic workflow to produce the PDFs; is there a way to set that as default or a plug in/script that do that?
You won't be able to set a default because the policy is saved with each document so you have to open the doc to make a change. If you are scripting your automated workflow the change could be made during the automation. This AppleScript changes the active document's policy to Preserve Embedded and resets all of the images to use their embedded:
tell application "Adobe InDesign CS6"
set d to active document
set CMYK policy of d to preserve embedded profiles
set g to all graphics of d
repeat with i from 1 to number of items in g
set profile of item i of g to "Embedded"
This works for images but won't work for files that could have more than one profile—PDF, AI, EPS—to catch those files the script would have to replace the file after the policy has been changed. But then you might have to worry about AI or PDF with black lines or text converting to 4-color blacks, so you might be better off leaving them alone.
it works perfectly. Really really thanks for all your help