Happily this isn't yet another "why do my RGB colors look different in 4cp output" question. But let me admit that I may be missing something obvious here.
I am working with InDesign and Illustrator documents that adhere to a brand-defined palette of various RGB colors. The documents are mainly intended for web viewing and download via PDF. However, some will now be printed via offset/web/digital.
I know InDesign and Illustrator can convert RGB documents to CMYK for print output; however, the design language here also defines the brand colors in predetermined CMYK colors. These were determined kind of arbitrarily based on a press check someone did long ago looking at what CMYK swatches on coated paper appeared closest to the RGB brand colors seen on-screen.
So I know that if I output to PDF with convert to US Web Coated (or whatever the vendor wants if not that), the final print output will look preeetty close to our CMYK swatches but not exactly. I'd like to get it exact. By adhering to the "correct" CMYK values, and so I want to swap out the RGB swatches with the CMYK swatches without resorting to any kind of color profile stuff. (Or—do I in fact need some kind of custom color profile stuff? This is not what I understand them to be intended for)
In Indesign, the only way I can think of to do this IN the source file is importing the CMYK palette, then deleting the RGB colors one by one from the document and replacing with the equivalent CMYK swatch. Or some even more onerous process in Illustrator. There are a lot of colors and a lot of files so want to avoid this.
So the problem is I can't think of or find a way to automatically map the RGB values to those assigned CMYK equivalents. Either in the source file or upon output (either way would work for me—although it would be nice if I didn't have to start maintaining two versions (RGB+CMYK) of each source file). In any case, is there some method or script or plugin to swap the RGB swatches with the assigned CMYK swatches programmatically?
Or is this something we should be asking the print vendor to do for us? (this seems doubtful).