Küppers’ color theory

Küppers’ color theory (in French théorie des couleurs de Küppers) theory of color perception and color rendering developed by Harald Küppers, not based on CIE recommendations or DIN standards and for this and other reasons controversial; Küppers redefined the maxima of the 3 cone sensitivity levels, unlike the CIE values 1931, namely 448 nm for blue (V, “violet blue”), 518 nm for green (G) and 617 nm for red (O, “orange red”). On this he based the first hifi color printing ink series in the world, the 7-part Küppers scale CMY-OGV-K, which was the model for similar scales, e.g. Pantone Hexachrome. Regardless of his special color theory, “The Great Kueppers Color Atlas” is still one of the most significant books on color rendering in the printing industry.