Stephen Marsh
Well-known member
I have been looking for a way to convert PDF Spot Alternate Colourspace from CMYK to Lab builds.
Both Acrobat’s native preflight and PitStop Pro 12 have the ability to convert from Lab to CMYK, but not the other way.
It in theory should be simple enough to create an action list to select any spot colour and remap it’s colour to the same named colour that uses a Lab based alternate colourspace…however it appears that all of Pantone library files use CMYK and not Lab as the alternate space and there is no Lab alternate colourspace option when creating a new spot inside PitStop Pro 12. I tried importing a .csv setup as Lab values for a named colour, but no dice.
I was attempting to overcome a proofing RIP issue where spot colour overprints were not working correctly in a specific problem file when the referenced spot lookup table in the RIP was Lab based, however if using the alternate colour from the spot in the PDF file (bypassing the RIP lookup table) the overprint was rendered correctly (when the PDF spot colour alternate was set to Lab or CMYK).
A niche case (most wish to remove Lab alternates) with multiple workarounds (such as remapping to another spot colour in the job that is Lab based), however it would have been good to simply remap all spots with CMYK alternate colour builds to Lab alternate colour builds in PitStop.
Stephen Marsh
Both Acrobat’s native preflight and PitStop Pro 12 have the ability to convert from Lab to CMYK, but not the other way.
It in theory should be simple enough to create an action list to select any spot colour and remap it’s colour to the same named colour that uses a Lab based alternate colourspace…however it appears that all of Pantone library files use CMYK and not Lab as the alternate space and there is no Lab alternate colourspace option when creating a new spot inside PitStop Pro 12. I tried importing a .csv setup as Lab values for a named colour, but no dice.
I was attempting to overcome a proofing RIP issue where spot colour overprints were not working correctly in a specific problem file when the referenced spot lookup table in the RIP was Lab based, however if using the alternate colour from the spot in the PDF file (bypassing the RIP lookup table) the overprint was rendered correctly (when the PDF spot colour alternate was set to Lab or CMYK).
A niche case (most wish to remove Lab alternates) with multiple workarounds (such as remapping to another spot colour in the job that is Lab based), however it would have been good to simply remap all spots with CMYK alternate colour builds to Lab alternate colour builds in PitStop.
Stephen Marsh
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