Economical computer tools now enable the creation of color documents at the desktop. An important step in producing output that will print with the desired color is the digital conversion of RGB color data to CMYK printing values. This process, traditionally performed by skilled craftsmen using electronic scanner controls, purportedly will be made routine by "color management systems" based on CIE colorimetry. This approach will likely succeed to varying degrees of success across the graphic arts landscape. With the hope of providing some background context this paper will step back, review some historical fundamentals, and describe a digital conversion algorithm that has proven quite successful in conventional graphic arts applications.