ISO 11664-4

ISO 11664-4
Title	ISO 11664-4
Othernames	CIE 11664-4:2019 (formerly CIE S 014-4)
Committee	International Organization for Standardization
Year	2019
Status	Published
Domain	Colorimetry, Color Measurement

ISO 11664-4 is an international standard that specifies methods for the determination of standard observer color-matching functions and related colorimetric calculations. It provides definitions and procedures used in colorimetry to relate spectral radiant energy to human visual response, underpinning color measurement across industries and linking to standards from organizations such as the International Commission on Illumination and the International Electrotechnical Commission.

Scope and Purpose

This part of the ISO 11664 series defines the criteria and recommended procedures for deriving the standard observer color-matching functions used in colorimetric calculations, aligning measurement practice with activities by International Commission on Illumination, International Organization for Standardization, International Electrotechnical Commission, European Committee for Standardization, and national bodies such as British Standards Institution, American National Standards Institute, and Deutsches Institut für Normung. It establishes uniformity for applications ranging from color quality assessment in Tokyo, product color control in Shanghai, spectral imaging in Silicon Valley, and archival color preservation at institutions like the British Museum and the Metropolitan Museum of Art.

Terminology and Definitions

ISO 11664-4 defines key terms used in colorimetry, referencing nomenclature adopted by Commission Internationale de l'Éclairage and aligning with vocabularies used by United Nations Educational, Scientific and Cultural Organization committees, standards boards in Berlin, and measurement laboratories in Geneva. Definitions include spectral power distribution, tristimulus values, chromaticity coordinates, luminous efficiency functions, and observer functions, with cross-references to terminology used by European Space Agency, National Institute of Standards and Technology, and the International Bureau of Weights and Measures.

Measurement Principles and Instrumentation

The standard details measurement principles linking spectral measurements to human visual response, describing instrumentation such as spectroradiometers, spectrophotometers, integrating spheres, and colorimeters produced by manufacturers serving markets in New York City, Munich, Seoul, and Zurich. It references measurement traceability frameworks used by metrology institutes like Physikalisch-Technische Bundesanstalt, National Physical Laboratory (United Kingdom), and NIST, and situates procedures within intercomparisons organized by bodies such as International Laboratory Accreditation Cooperation and Asia Pacific Metrology Programme.

Standardized Observer and Colorimetric Calculations

ISO 11664-4 prescribes the standardized observer functions and the computational formulas for converting spectral data to CIE tristimulus values, chromaticity coordinates, and correlated indices used in colorimetry practice at organizations like CERN, National Aeronautics and Space Administration, and European Southern Observatory. It aligns the standard observer definitions with experimental foundations established in historical studies associated with laboratories in Cambridge, Princeton University, and University of California, Berkeley. Computational steps reference matrix transformations and chromatic adaptation methods used in projects involving Sony Corporation, Samsung Electronics, and Panasonic Corporation.

Calibration, Uncertainty, and Test Methods

The document provides recommendations for calibration of instruments against reference sources, procedures for establishing measurement uncertainty, and test methods for validating observer-based conversions, consistent with principles advocated by International Laboratory Accreditation Cooperation, Joint Committee for Guides in Metrology, and national accrediting agencies such as National Accreditation Board for Testing and Calibration Laboratories. It outlines uncertainty budgets applicable to campaigns like interlaboratory comparisons among institutions in Oslo, Toronto, and Sydney and links to quality assurance practices used by manufacturers like X-Rite and research centers at Massachusetts Institute of Technology.

Applications and Industry Use Cases

ISO 11664-4 underpins color management workflows across industries including textiles in Dhaka, printing houses in Rotterdam, display manufacturing in Shenzhen, automotive coatings by companies such as Toyota Motor Corporation and Volkswagen Group, and lighting design practices used by firms in Milan. It supports colorimetric needs in conservation at Smithsonian Institution, remote sensing projects by European Space Agency and NASA, film and broadcast color grading in Los Angeles and Mumbai, and medical imaging initiatives at hospitals affiliated with Johns Hopkins University and Karolinska Institute.

Category:Colorimetry standards