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1. Re: Color Management in Acrobat: What is it doing?
bpylant Apr 6, 2010 8:15 AM (in response to bpylant)Anyone? Bueller? Bueller?
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2. Re: Color Management in Acrobat: What is it doing?
Phillip Jones Apr 6, 2010 2:12 PM (in response to bpylant)I read somewhere in the forums a few days ago that there is a setting in the Advanced> Print Production menu about Color conversion. you need to turn that off you want no color conversion.
This may work or may not. While in Acrobat do help and look up Color Conversion. see what shows up.
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3. Re: Color Management in Acrobat: What is it doing?
bpylant Apr 7, 2010 7:27 AM (in response to Phillip Jones)The Convert Colors dialog is a function, for when you actually want to perform a color conversion on a PDF. It's really usefull for when we receive PDFs from customers that are over total ink limit, have full-color neutrals that are too rich in the CMY, etc. If we need to modify customer files for production purposes (which is, well, most of them these days!) I'd rather have access to the original layouts and support files. But when all they can give us are the PDFs the Convert Colors funtions are life savers.
What I need Acrobat to do -- if it's possible -- is display a PDF correctly using the embedded profiles when present, and use the default profile that is set up in the prefs when the PDF (or any individual images in the PDF) are untagged. Pretty much as Photoshop behaves when you open a tagged or untagged file.
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4. Re: Color Management in Acrobat: What is it doing?
Printer_Rick Apr 12, 2010 4:23 PM (in response to bpylant)bpylant wrote:
What I need Acrobat to do -- if it's possible -- is display a PDF correctly using the embedded profiles when present, and use the default profile that is set up in the prefs when the PDF (or any individual images in the PDF) are untagged. Pretty much as Photoshop behaves when you open a tagged or untagged file.
I posted a few minutes ago in the other forum.
This may help:
1. To render a tagged CMYK image that is not in the same space as the Simulation profile in Output Preview, Acrobat assumes a conversion to the Simulation profile (not a reassignment). So if you have a fully saturated Sheetfed Coated image, and change the Simulation to Japan Newspaper, the image will look duller and flatter because of the change in print condition.
2. If you have a tagged CMYK image and you change the Simulation Profile, you should notice that the CMYK number readings change. Again, Acrobat is assuming a conversion (numbers change) instead of reassignment (numbers are preserved). This behavior is somewhat troublesome, because it can yield false CMYK readings if the calibrated images never do get converted. But it must behave this way, Total Ink Limit being such an important consideration.
3. If you do not have Output Preview turned on, the Simulation profile used by Acrobat will default to your Acrobat working CMYK – UNLESS the PDF has an Output Intent, in which case the Output Intent should be honored by Acrobat, even with Output Preview turned off
4. PDF's with CMYK Output Intents are PDF/X files. Usually all CMYK content in these is Device color (untagged). The Output Intent may seem like tag of sorts – and it is a global document tag – but all CMYK content is assumed to be finalized with nor further conversions necessary (no "source" CMYK). If your have any source color remaining it would be RGB (as you might see with PDF/X-4).
5. Acrobat can't behave exactly like Photoshop because it has to deal with a multitude of images, not just one at a time. You can't have one image on a page displaying in Sheetfed Coated, another in US Web, and still another in newsprint. That is not to say the tagged spaces are not honored, but all the images must be rendered in a common space.
6. When you are dealing with multi-page PDF documents for print, the source app is often InDesign. InDesign's default behavior for CMYK is to Preserve Numbers when images are placed. Not only that, the PDF export settings most commonly used by InDesigners for commercial print do not include CMYK tags. You may have an Output Intent if the file is PDF/X, but you still can never be sure that all the images actually do correlate with the Output Intent, since InDesign discards profiles (usually) in all imported CMYK.
7. Illustrator's default behavior when placing images is also to Preserve Numbers, so any CMYK Photoshop placed into Illustrator CMYK is normally assigned to the Illustrator document space, even if the image is in a different space.
8. Because of InDesign and Illustrator default behaviors, mystery CMYK in PDFs is extremely common and can be a big problem in a commercial print environment. It is quite ordinary to see nothing but Device CMYK in PDFs (just look at the Press Quality setting). Reassigned CMYK is also a possibility. Whenever you have a multitude of CMYK images getting assimilated into one common document with numbers preserved, the final output could end up being a riddle wrapped inside an enigma.
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5. Re: Color Management in Acrobat: What is it doing?
bpylant Apr 13, 2010 9:24 AM (in response to Printer_Rick)Very useful, thanks so much for taking the time! I'll need to go grab some coffee to help me digest it all...
A little info on why I'm asking: last year we moved to a softproofing setup at the press, installing a calibrated monitor next to the lightbooth. This has been working very wel; Acrobat was set up to use the same profile we use for our hardcopy proofing (which was an ICC I built from the press) and so the PDFs display properly. (These are post-RIP PDFs that are the same that are used to image the plates; we utilize a RIP-once-output-many workflow here.)
The press profile we're using is not perfect, we're a short-run / pleasing color type of shop, so it's a bit more of a moving target than other shops are. Moving forward I'd like to build a better press profile; the issue I'm concerned with is how to deal with legacy files (the PDFs we're currently using that have no profiles).
What I was hoping to do, once we create the new profile, is to tag those ripped PDFs with the profile, and then instruct Acrobat to use the profile specified in the Color Settings for any PDFs that aren't tagged. We'd set the Color Settings to the old profile to account for the untagged files, and then the new ones would be tagged so they would display correctly as well. But perhaps that's not the way to go (because it sounds like it won't work quite like that?)
Hopefully I'm explaining this well enough that it makes sense... and please don't hesitate to tell me that I'm barking up the wrong tree! We've only recently begun to implement any sort of formal color management (after years of flying by the seat of our pants), so there are certainly elements I'm not fully understanding (or not properly visualizing how to best implement some of the things we'd like to do).
Thanks!
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6. Re: Color Management in Acrobat: What is it doing?
Printer_Rick Apr 13, 2010 2:57 PM (in response to bpylant)The legacy PDFs should display as if they were already in your Acrobat working CMYK. This is assuming all of these are completely decalibrated and have no Output Intents.
The new PDFs will display as a conversion to your Acrobat working CMYK. If the PDF is already in the same as the Acrobat working, numbers are preserved (no conversion is necessary).
The only time your Acrobat working gets overridden is when you have an Output Intent. (Or, if you forcefully change the Simulation profile in Output Preview, but don't do that).
That's not to say Output Intents are not good. In fact they are essential. You might be able to make very good use of them.
Let's say you have one press, with the soft proof station. But you use five different stocks. You can ICC profile each of these stocks if you wanted, and now you have five separate printing conditions.
Now you create workflows in your RIP system for each of the five conditions. In each workflow, the incoming data gets converted to the appropriate Output Intent. The RIP PDF output will have this Output Intent. Acrobat will honor it at the press so you don't have to keep switching your working space to see the right numbers and appearance.
For the legacy jobs you have to preserve numbers in the RIP. But they are all Device aleady. So if you submit one to the workflow, the RIP will say "Hey, this is already in the destination". All it does is tag on the Output Intent, no numbers change. Check the results though, to make sure numbers don't change, if you don't want them to.
Remember all the CMYK in a PDF with an Output Intent is usually decalibrated. But that's OK at the press. Acrobat says "this CMYK already matches the Output Intent. No further conversions are necessary. The numbers in Output Preview are what's in the file, and the soft proof needs to correlate with the Output Intent"



