I work in prepress production at a publishing house and often times only have access to .PDF cover files which contain spot (pantone) colors from their former offset printing days. Because I set up these files for digital printing, spot colors are NOT an option.
What is the most professional way to convert these spot colors to process? I see features in Acrobat that claim to map them to the (nearest?) process value but I wish to understand more about this acrobat feature and if more precise alternatives exist, pitfalls to avoid, etc.
The thing is it depends. CMYK has a different possible range of colors than spot colors, this range is called color gamut. So it may be that your chosen spot color is outside the gamut of your regular CMYK printer.
This gets you in a bind, since now you need to decide what alternate color to use. For this you need to have a colorimeter to decide what your equipment is capable of and so that you can soft proof the color on screen, or profile your printer. You may be even unluckier, the Pantone color may be outside the gamut of your monitor.
You could also use a more advanced printer with several more colors than the standard CMYK, like a indigo digital press that could do 97% of your Pantone chart somewhat accurately.
However, its hard to get you good answers as we dont just know. For example Why is it you want to print CMYK?
- Cost, if so then a printer capable of your range may be more expensive than to use Pantone (or may not).
- You need to do this with a locally available printer. Again now its a question of what that printers gamut is.
In the end theres no safe way to do this unless you know whow the color maps into your gamut space. Where you need to print CMYK and why!