Billmeyer and Saltzman's Principles of Color Technology, 4th Edition

Chapter 9Optical Modeling of Colored Materials

There are many applications where it is useful to know the relationship between colorants and their resulting color when mixed. For thousands of years, artisans have used their experiences to develop this relationship for ceramics, textiles, paints, and glass, to name a few. This experience was handed down to the next generation through apprenticeships. Trade guilds, developed during medieval times, exemplify the apprentice approach. The introduction of spectrophotometers capable of measuring opaque samples opened the possibility of using the spectral data to establish a relationship between the materials' spectral properties, concentrations, and the resulting spectra following mixing. Colorimetric coordinates were calculated from the mixture's spectrum, defining the mixture's color. Having established such a relationship, it should be possible to reverse the relationship. This facilitates answering the following questions. What are the concentrations necessary to produce a particular color, that is, predicting a color formula (or recipe)? Are the selected colorants the best colorants to use, either leading to the least amount of metamerism when matching a standard, or the least amount of color inconstancy when the standard is colorimetric? Do the selected colorants minimize color variability caused by process variability? When the batch does not match, how is the formula adjusted to improve the match?

There are several ways to establish ...