colordifference

Colordifference is a term used in color science to describe the perceptual difference between two colors. It provides a numerical way to express how similar or different colors appear under specified viewing conditions, devices, and materials. In practice, colordifference is usually quantified with color-difference metrics derived from standardized color spaces such as CIE L*a*b*.

The most common approach uses Delta E values. Delta E*ab (CIE76) calculates the Euclidean distance between two color coordinates in L*a*b*. More recent metrics, such as Delta E94 and Delta E2000 (CIEDE2000), introduce adjustments for perceptual nonuniformities in lightness, chroma, and hue to better match human judgment. Color-difference values depend on the chosen color space, reference white, and lighting conditions, making consistent interpretation contingent on standardized viewing setups.

Applications of colordifference include quality control and color matching in printing, textiles, plastics, and paints; evaluation of color reproduction across devices (monitors, printers, cameras); and verification of brand color consistency in manufacturing. It is also used in color-management workflows to set tolerances and assess deviations during production.

Limitations exist: perceptual differences are influenced by viewing conditions, observer variability, and metamerism (two colors matching under one light source but not another). Consequently, color-difference metrics are guidelines rather than absolute measures and are most effective when paired with well-defined illumination and observation standards.

See also: color space, colorimetry, Delta E, metamerism, CIE 1931 and CIE 1976 standards.