Spectral Print Reproduction: Modeling and Feasibility

Abstract

Towards the goal of spectral print reproduction a few obstacles can be found comparing to reproduction of colorimetric match. Human visual system is able to sense wide spectrum of colors and placing that range on substrate, weather paper or any other, requires skills. Traditional printing reproduction is built on metamerism phenomena and now the new challenge to overcome that constraint is set. To create the communication with print mechanism is very important and for that reason spectral printer modeling represents the crucial step. With this process characterization of the printer is done. This depends on the data given and optimal way of its use needs to be established. With forward printer model the relation between the colorant combination and the resulting spectral reflectances printed on substrate is defined. The inverse process enables printer control to define the colorant separation from spectral refelectances to precise values. Very important step in the whole process is not only measuring the printed material but overcoming time and resources waste with estimating spectral reflectances and combining them with already measured ones. Several models were tested by now and our contribution is consisted of employing Kubelka-Munk theory for estimation step before testing it with cellular model that makes printed cell smaller than unity and therefore more precise. Among the rest possible theories for estimation Kubelka-Munk theory was chosen due to its consideration of light scattering. This was mainly because the study samples used for spectral reproduction were garnament products. Before the target spectral reflectances values can be printed the feasibility of the process should be considered. Possibility for making that process as much automated as it can be was the main motivation in creation of feasibility of spectral reproduction algorithm