Convert CMYK PDF into spot colors (colours)
Is it possible to pre-process (in batch) PDFs that are in CMYK format to separate out into spot colours?
I have a collection of PDFs that are in CMYK but I require them to be in a 2 spot colour format.
The colours are red and black. The black (K) is fine, but the red spot needs to be a merge of the Magenta & Yellow.
Is this possible at all? I'd prefer something that would be able to separate spots based on a given colour rather than merging colours as that becomes very limited.
I've looked in adobe acrobat X pro and that doesn't seem to do what I want. I could probably do it manually in photoshop but it would be a long winded process for the large amount of PDFs I have.
Answer
I'm guessing this problem was long solved, but just for completeness; yes, this can be done. There are a number of commercial tools that do exactly this very easily actually.
1) If I'm not mistaken, the latest version of Adobe Acrobat actually contains a lot more PDF file correction possibilities than previous versions, which means it should be able to do this.
2) There are tools like callas pdfToolbox (warning, I'm affiliated with this company/product) that can pre-process a PDF file pretty much any which way you want.
In general though I think the first question would be why you go through the RGB to CMYK step - the tools than can do this kind of remapping would equally be able to simply go from Black and Red RGB directly to two named spot colors, avoiding the unnecessary CMYK conversion.
By the way, if what you are trying to obtain is a PDF where you can switch one color off easily (such as for example to hide the correct answers), there are probably better ways to do this. Such as putting all red text on one layer for example, while putting all black text on a different layer (or OCG - optional content group as PDF calls them). This would give you to capability to switch colored text on or off at will, even in something like Adobe Reader.