SIST EN ISO/CIE 11664-6:2022 PDF

Overview

EN ISO/CIE 11664-6:2022 - Colorimetry Part 6 - specifies the CIEDE2000 colour‑difference formula (commonly referred to as ΔE00 or CIEDE2000). The standard defines the method for calculating perceptual colour differences from CIELAB L*, a*, b* coordinates (as produced according to ISO/CIE 11664‑4). It is intended for comparing two colour stimuli perceived as belonging to reflecting or transmitting objects and for displays only when they simulate such objects with appropriately normalized tristimulus values. Emissive or specular primary light sources are excluded.

Key topics and requirements

• Input space: Requires CIELAB L*, a*, b* values computed per ISO/CIE 11664‑4.
• Reference conditions: Recommended viewing and measurement conditions include illuminant simulating CIE D65, 1 000 lx illuminance, normal colour vision observer, neutral grey background (L* = 50), object viewing mode, sample subtending >4° visual angle, edge contact between samples, homogeneous samples and colour‑difference magnitudes in the 0–5 CIELAB range.
• Calculation method: Defines modified CIELAB coordinates (L′, a′, b′), derived chroma and hue (C′, h′), and difference terms ΔL′, ΔC′, ΔH′. The formula applies lightness, chroma and hue weighting functions (S_L, S_C, S_H), a hue‑dependent T function, and a rotation term R to account for chroma–hue interactions. Angular quantities are evaluated in degrees.
• Parametric factors: kL, kC, kH are provided to correct for deviations from the reference conditions when necessary.
• Normative references and limitations: References include ISO/CIE 11664‑4 and CIE S 017. The standard notes limitations for very small differences (see CIE 230:2019 for ΔE