physical color mixture, absorptive interference

physical color mixture, absorptive interference (In French synthèse soustractive, interférence d’absorption) incorrectly called “subtractive color mixture” (as opposite of additive color mixture); mutual absorptive influence of object colors (e.g. merged opaque paints, superimposed printing ink layers, transparent color filters arranged in series). In absorptive interference, nothing is mathematically subtracted; instead, all those parts of the irradiated light that are not re-emitted and thus are not involved in the formation of a color stimulus (Lambert-Beer’s law) are absorbed (i.e. multiplied with absorption degrees < 0). The maximum possible result “black” is to be understood as total absorption, that is, the complete attenuation of light. The absorptive primary colors are the complementary colors of the additive color mixture, that is, cyan, magenta, yellow (CMY). Applications: “autotypical color mixing” in multi-color halftone printing, color films, color formulating systems.