International Commission on Illumination

Organization

Milestones

• In 1924 it established the standard photopic observer defined by the spectral luminous efficiency function V, followed in 1951 by the standard scotopic observer defined by the function V’.
• Building on the Optical Society of America's report on colorimetry in 1922, the CIE convened its eighth session in 1931, with the intention of establishing an international agreement on colorimetric specifications and updating the OSA's 1922 recommendations based on the developments during the past decade. The meeting, held in Cambridge, United Kingdom, concluded with the formalization of the CIE 1931 XYZ colour space and definitions of the 1931 CIE 2° standard observer with the corresponding colour matching functions, and standard illuminants A, B, and C.
• In 1964 the 10° CIE standard observer and its corresponding colour matching functions as well as the new standard daylight illuminant D6500 were added, as well as a method for calculating daylight illuminants at correlated colour temperatures other than 6500 kelvins.
• In 1976, the commission developed the CIELAB and CIELUV colour spaces, which are widely used today.
• Based on CIELAB, colour difference formulas CIEDE94 and CIEDE2000 were recommended in the corresponding years.