CIEstandard

CIEstandard is a term sometimes used to refer to the collection of colorimetric and photometric standards published by the Commission Internationale de l'Éclairage (CIE). It denotes the reference data and methods that provide a common basis for specifying and communicating color in scientific, industrial, and consumer applications. Although not an official designation, CIEstandard is used to describe the suite of standards related to observers, illuminants, color spaces, and color-difference calculations that originate from the CIE.

The concept centers on standard observers, standard illuminants, and standardized color spaces. Standard observers include the CIE 1931 2-degree observer and the CIE 1964 supplementary 10-degree observer, whose color-matching functions form the basis for converting spectral inputs to tristimulus values. Standard illuminants specify reference spectral power distributions such as D65 (representing average daylight), D50, A (incandescent), and various fluorescent illuminants. These references underpin consistent color measurement across devices and processes.

Standard color spaces, notably CIELAB and CIELUV, provide perceptually relevant coordinates for describing color, while chromaticity diagrams—x,y and u’,v’—offer compact representations of hue and saturation independent of luminance. Color-difference formulas, from the traditional CIE76 to later refinements like CIEDE2000, quantify perceptual differences between colors, supporting quality control and matching tasks.

Applications of CIEstandard concepts include product color specification, printing and display calibration, lighting design, archival and museum work, and digital color management workflows. Limitations include reliance on average observer data, potential metamerism under varying lighting, and ongoing updates as perceptual models evolve.

See also: CIE, standard observer, standard illuminant, CIELAB, CIELUV, CIEDE2000.