Oh hey that's a good idea! Probably calculating the lightness, hue and chroma for the source CMYK color is going to be faster than searching for it in the DB. Also I'm using the DB because it provides mappings for all the CMYK colors. If I just work with CIECAM02, and run the math in reverse to get a CMYK color, there's no guarantee that the numbers that come out will actually be valid CMYK values: they might be greater than 100 or less than 0 and either case is not a valid CMYK value. This happens because CIECAM02 tries to model all the colors that exist in the visible spectrum and CMYK only represents all the colors which can be made by mixing cyan, magenta, yellow and black inks and thus there are fewer colors in CMYK than CIECAM02. Still I might be able to try "looking around" in the case that the computer calculates invalid CMYK and that might be faster than using the DB.