Quote:I opened Krita and tried to follow the screenshot. Everything was fine but there is only one colour profile which is Chemical Proof (default).
At least it has a CMYK profile, which is more than Gimp has. You need to add your own. For printing ask the printing company which one they use. Some printing equipment / papers use a specific profile. For more general offset printing often ISO coated v2 (ECI) (Coated FOGRA39)
You can find profiles to download here: https://www.color.org/registry/index.xalter (edit: ahh - you sneaked that in while I was writing)
Quote:This is the CMYK option I found in GIMP 2.10
Just a handy shortcut eg. Magenta = a mix of RGB values, no guarantee that the color is not out-of-gamut.
If you search there are some really good pages on the subject, often a bit technical.
For some reason I have this one noted. https://trade.4over.com/faq.php Look at section 2 What color mode should my files be and the usual advice You should always start and finish your designs in CMYK color mode. Of course not possible with Gimp but once you realise that bright yellow used is not going to print the way you want it, you are part of the way there.