Theory of Colours
The RYB primary colors became the foundation of 18th-century theories of color vision, as the fundamental sensory qualities that are blended in the perception of all physical colors, and conversely, in the physical mixture of pigments or dyes. These theories were enhanced by 18th-century investigations of a variety of purely psychological color effects, in particular the contrast between "complementary" or opposing hues that are produced by color afterimages and in the contrasting shadows in colored light. These ideas and many personal color observations were summarized in two founding documents in color theory: the "Theory of Colours" (1810) by the German poet Johann Wolfgang von Goethe, and "The Law of Simultaneous Color Contrast" (1839) by the French industrial chemist Michel Eugène Chevreul. Charles Hayter published "A New Practical Treatise on the Three Primitive Colours Assumed as a Perfect System of Rudimentary Information" (London 1826), in which he described how all colors could be obtained from just three.