Quality limits in color printing with more than three primary colors

A widely used type of a mathematical color printing model, the Neugebauer model, is investigated. In a three color printer the produced colors depend on the spectral characteristics of the three primary inks as well as on the driving parameters, which are the CMY values. Using the so-called Neugebauer equations it is possible to obtain the reflectance spectrum and finally the color, depending on the incident illumination. At first a strategy is presented to calculate optimal spectral reflectances for the three primaries together with the optimal driving parameters CMY. Afterwards the three color Neugebauer printing model is extended to an arbitrary number of primary inks and evaluate the achievable performance gain for 4 and 5 inks.