CHEVREUL, Michel-Eugène

Œuvre majeure sur la dénomination des couleurs, l’Exposé de Michel-Eugène Chevreul demeure “just as a monumental... the norms it established for naming colors are still valid and in use today” (Moshe Ron). En s’appuyant sur ses propres travaux relatifs à l’optique des couleurs (De la loi du contraste simultané des couleurs, 1839), Chevreul parvient à résoudre le problème de la définition et de la représentation des couleurs, en donnant ici de multiples et précises analogies.

“Chevreul used as fundamental points of comparison 3 definite rays of red, yellow, and blue. He placed these 3 colors at equidistant points on the circle and interpolated 23 color mixtures in each of the 3 intervenings sectors, obtaining a chromatic circle of 72 colors. In addition to this circle he prepared 8 others in which the colors were toned down with known proportions of black. To compare shades of colors he mixed the normal colors with known proportions of white in the other direction, obtaining complete scales of colors in which pure white and pure black were the extremes and the pure color was in the middle of the scale. In this way Chevreul derived from the chromatic circle of pure colors 1,442 different tones all of which were exactly defined” (Albert Costa).

Le principe de la juxtaposition des couleurs, laissant à l'œil le soin de reconstituer les couleurs intermédiaires, influença les peintres impressionnistes et pointillistes.