Recently, with the advent of printers with more than four colorants, the development of characterization and calibration techniques for these printers has been an important area of research in color printing. In addition to the “hi-fi” printers having colorants such as green, orange, red, blue and violet to increase the gamut of traditional CMY K (cyan, magenta, yellow, black) printers, CMYKcm printers which have light dye load colorants light cyan (c) and light magenta (m) have also become popular. In this paper, we investigate the CMYKcm printers. We propose an spectral model based approach for the problem of color printer separation in CMYKcm printing. We employ a parametric spectral model for color printers based on Yule-Nielsen modified spectral Neugebauer equations to characterize a CMYKcm printer. We find the Yule-Nielsen parameter from a least squares regression over a training set of spectral measurements. We then apply the spectral model for the CMYKcm printer and to compute the color separation function from CMY K to CMYKcm.