Color space for papers: CMYK or RGB? This is a bit technical question, but might be frequent enough in this community.

My PI and I disagree on which color space to use for figures and manuscripts.

I like CMYK, because I care about how it prints out. Even for online-only publications, a lot of people still print them out to read them. (I also care about black &amp; white printing and color blind friendly colors, but that's another story). My main tool for editing figures is Adobe Illustrator with CMYK default (of course I can change it).

My PI likes vibrant red and blue colors which are in RGB space and not in CMYK. I agree that it has better visibility on screen or presentations. It would also be more flexible for switching for different requirements since RGB space is in general larger.

What is the best practice for preparing manuscripts with color figures (and possibly color text)? Do you make the figures in RGB which has a larger color space, and only adjust to CMYK when sending the accepted version to the publisher? Or let the publisher figure it out? (What about self-archived preprint versions?)

(I don't want to worry about color space consistencies and do more research!)
You follow the publisher's instructions.

If your target journal asks for CMYK, you give them that.

If they ask for RGB, you give them that.

If they (are one of the few IME that) express no preference, then have a think about whether the charts will be viewed more on screen (use RGB) or printed on 4-colour printers (use CMYK).