CIELAB — LLMpedia

CIELAB
Holger kkk Everding · CC BY-SA 4.0 · source
Name	CIELAB
Alternative names	CIE Lab, CIE 1976 (L, a, b)
Designer	CIE
Publication	1976
Based on	CIE XYZ
Uses	color measurement, printing, imaging, textiles

Contents

CIELAB CIELAB is an international color space established to provide a perceptually uniform model for color appearance, created by the Commission Internationale de l'Éclairage in 1976 alongside standards from organizations like the International Organization for Standardization and adopted widely in industries including Kodak, Xerox, Pantone, Agfa-Gevaert. The model links colorimetric data from devices such as the Minolta, GretagMacbeth spectrophotometers and practices at institutions like the National Physical Laboratory (United Kingdom), the National Institute of Standards and Technology, and laboratories in Fujifilm workflows to support cross-industry communication among entities including Apple Inc., Adobe Systems, Microsoft, Hewlett-Packard, Canon Inc..

History

CIELAB emerged from postwar initiatives by the Commission Internationale de l'Éclairage following earlier systems like the Munsell color system and developments by scientists such as David MacAdam, W. David Wright, John Guild, and institutions like the Royal Society. The 1931 CIE 1931 color space and later research by groups at Eastman Kodak Company, National Physical Laboratory (United Kingdom), and committees involving representatives from ISO/TC 42 led to standardization meetings in which contributors from RCA Corporation, Bell Labs, General Electric, Kodak and academics influenced the 1976 specification. Subsequent revisions and practical adoption were shaped by standards bodies including the International Electrotechnical Commission and applied by manufacturers such as Xerox, Agfa-Gevaert, Heidelberg, and research centers like MIT, Stanford University, University of Cambridge.

The definition of the space depends on tristimulus values derived from the CIE 1931 color space and the standard observer functions originally measured by teams at Eastman Kodak Company and refined at the National Physical Laboratory (United Kingdom), with adaptations referenced by the International Organization for Standardization and the Commission Internationale de l'Éclairage. Conversion from CIE XYZ to the model uses nonlinear transformations introduced by committees including CIE working groups and researchers influenced by work at RCA Corporation, Bell Labs, and laboratories at University of Oxford. The space defines a lightness axis supervised through collaborations among standards institutions such as ISO/TC 130 and companies like Pantone to serve color communication in print and digital ecosystems dominated by firms like Adobe Systems and Apple Inc..

The coordinate system uses three components denoted L* (lightness), a* (green–red), and b* (blue–yellow), derived from computations that reference the CIE 1931 color space and illuminants standardized by the Commission Internationale de l'Éclairage such as illuminant D65 and illuminant A used in laboratories like National Institute of Standards and Technology and industries including Kodak and Fujifilm. Conversion formulas and nonlinearity parameters trace back to research from groups at RCA Corporation, General Electric, and academics at Princeton University, University of Cambridge, and MIT. The components are used in workflows across devices from Canon Inc., Nikon Corporation, Hewlett-Packard, and Epson for color balancing, profiling, and gamut mapping in concert with standards from International Color Consortium implementations adopted by Adobe Systems and Microsoft.

Color difference metrics such as ΔE*ab originated with the model and were later refined into perceptual formulas like CIE94 and CIEDE2000 through committees and researchers at institutions including Commission Internationale de l'Éclairage, ISO, National Physical Laboratory (United Kingdom), and universities such as University of Leeds and University of Manchester. These metrics are used in quality control by corporations like Toyota, Ford Motor Company, Boeing, and Samsung Electronics and referenced in standards by International Organization for Standardization and ASTM International for tolerancing in textiles, coatings, and plastics by suppliers like DuPont and BASF. Research into ΔE variants involved contributors from MIT, Stanford University, Rensselaer Polytechnic Institute, and industrial labs at Kodak and Xerox.

CIELAB underpins color management in imaging software from Adobe Systems, operating systems by Microsoft and Apple Inc., and device profiling workflows promoted by the International Color Consortium, with adoption in printing houses using Heidelberg presses and digital printers by Hewlett-Packard and Epson. Industries employing the model include automotive manufacturers such as Toyota and General Motors, textile firms like H&M and Inditex, paint producers including Sherwin-Williams and AkzoNobel, and display makers like Samsung Electronics and LG Electronics. Scientific applications appear in laboratories at NASA, European Space Agency, NOAA, and research groups at MIT and University of Cambridge for remote sensing, while cultural heritage institutions such as the British Museum and Smithsonian Institution use it for conservation documentation.

Critiques of the model emerged from psychophysical studies at University of Cambridge, Massachusetts Institute of Technology, and University College London that compared uniformity against advanced models like CIECAM02 and findings from perceptual laboratories at Harvard University and Stanford University. Limitations noted by standards committees in the Commission Internationale de l'Éclairage and researchers at NIST include departures from uniformity in high chroma regions affecting industries such as Pantone, Heidelberg, and DuPont, leading to updates in metrics (CIEDE2000) and alternatives developed by teams at Ghent University, Aalborg University, and corporate labs at Sony Corporation and Samsung Electronics. Further concerns arise in color appearance modeling for contexts studied by researchers at University of California, Berkeley, University of Pennsylvania, and the Max Planck Institute for Psycholinguistics where environmental factors and complex illuminants require models like those from CIECAM02 and spectral approaches used by X-Rite and GretagMacbeth.

Category:Color space