Calculateur de distance des couleurs (Différence perceptive)

DeltaE (ΔE) is a metric for measuring the perceptual difference between two colors as perceived by the human eye. A deltaE of 0 means the colors are identical. Values below 1 are imperceptible to most people. Values between 1-2 are barely noticeable. Above 5, the difference is obvious. DeltaE is the industry standard for color quality control in printing, manufacturing, display calibration, and brand color consistency.

CIE76 is the simplest formula — a straight Euclidean distance in LAB color space. CIE94 improves on it by weighting the lightness, chroma, and hue components differently to better match human perception. CIEDE2000 is the most accurate and complex formula, adding corrections for blue region inaccuracy, lightness dependence, and hue rotation. For critical color work, CIEDE2000 is the recommended standard.

The RGB color space is not perceptually uniform — equal numeric changes in RGB values do not produce equally visible color changes. The CIE L*a*b* color space was specifically designed to approximate human vision, where equal distances correspond to equal perceived differences. Converting to LAB first ensures that the deltaE calculation reflects how humans actually see color differences, not just mathematical differences in pixel values.

Most brand guidelines specify a deltaE tolerance of 2-3 for printed materials and digital displays. A deltaE below 1 is considered imperceptible. Between 1-2, only trained observers notice the difference. Between 2-3.5, untrained observers begin to notice. Above 5, the difference is obvious to everyone. For critical applications like product packaging or luxury brands, tighter tolerances of deltaE less than 1 may be required.