Where can I find the CMYK codes for colors like Prussian Blue?

Hi

I would suggest you buy or look for, a Color guide from let say Pantone. Expensive I know, but check their guide. They have CMYK and RGB numbers attached to each color swatch on their paper printed colour guides.

Another thing G I would suggest, is to open Color manager in CorelDRAW or Photo-Paint. And open a few of the color palettes in their, and see if you can hoover various color swatches showing the color names.

Or go on the Internet, and write in search Prussian Blue CMYK