couleur

Couleur is the term used in French to denote color, the perceptual attribute of objects and light that enables sight. In physics, color corresponds to the portion of the electromagnetic spectrum visible to humans, roughly 380 to 740 nanometers, or to mixtures of wavelengths. An object's color is determined by which wavelengths are reflected or transmitted by its surface; the rest are absorbed. Colors can also be produced by additive mixtures of light, as in digital displays, or by subtractive mixtures of pigments, as in painting.

Human color perception depends on three types of cone photoreceptors in the retina, sensitive to short, medium, and long wavelengths. The brain interprets the combined signals as distinct colors. Colors are commonly described by hue, saturation, and brightness (or value). For precise work, color is quantified using color spaces and colorimetry, such as CIE XYZ, and perceptual spaces like CIELAB and CIELUV. Device-dependent models include RGB for screens and CMYK for printing; devices can be managed to maintain color consistency through profiles and color-management workflows.

Culturally and linguistically, color names and distinctions vary. Some languages have a few basic color terms; others recognize many hues. Color vision deficiencies affect a portion of the population, influencing color perception and naming.

Historically, Newton demonstrated that white light contains a spectrum of colors, while Goethe emphasized perceptual and contextual aspects. Today, color is central to art, design, branding, lighting, and science, informing perception, communication, and aesthetics.