The methods manufacturers use in correlating color measurement with sensory aspects of food color are discussed. Physical aspects of color must be understood to achieve the desired effects. The science of color physics makes it possible to quantify the variables. Such quantification is very important in quality control. The human eye is the final arbiter in the food industry and acceptance by the consumer is the goal of manufacturers, but colorant location and migration, light-scattering qualities, and crystal size influence final appearance. Topics discussed include color vision, the eye, the brain, espresso coffee foam, reflectance spectra for milks with varying fat content, the Commission Internationale de l'Eclairage (CIE), the trichromatic theory, and the CIEL*a*b* system established in 1976, and the Kubelka-Munk theory, which involves additivity.