ASTM_D_2244_-_22.pdf

Designation:D224422Standard Practice forCalculation of Color Tolerances and Color Differences fromInstrumentally Measured Color Coordinates1This standard is issued under the fixed designation D2244;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.INTRODUCTIONThis practice originally resulted from the consolidation of a number of separately publishedmethods for the instrumental evaluation of color differences.As revised in 1979,it included four colorspaces in which color-scale values could be measured by instruments,many of which were obsolete,and the color differences calculated by ten equations for different color scales.The sections onapparatus,calibration standards and methods,and measurement procedures served little purpose in thelight of modern color-measurement technology.The revision published in 1993 omitted these sections,and limited the color spaces and color-difference equations considered,to the three most widely usedin the paint and related coatings industry.Aprevious revision added two new color tolerance equationsand put one of the color difference equations from the 1993 version in an informative appendix forhistorical purposes.1.Scope1.1 This practice covers the calculation,from instrumentallymeasured color coordinates based on daylight illumination,ofcolor tolerances and small color differences between opaquespecimens such as painted panels,plastic plaques,or textileswatches.Where it is suspected that the specimens may bemetameric,that is,possess different spectral curves thoughvisually alike in color,Practice D4086 should be used to verifyinstrumental results.The tolerances and differences determinedby these procedures are expressed in terms of approximatelyuniform visual color perception in CIE 1976 CIELABopponent-color space(1),2CMC tolerance units(2),CIE94tolerance units(3),the DIN99o color difference formula givenin DIN 6176(4),or the CIEDE2000 color difference units(5).1.2 For product specification,the purchaser and the sellershall agree upon the permissible color tolerance between testspecimen and reference and the procedure for calculating thecolor tolerance.Each material and condition of use may requirespecific color tolerances because other appearance factors,(forexample,specimen proximity,gloss,and texture),may affectthe correlation between the magnitude of a measured colordifference and its commercial acceptability.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:3D1729 Practice for Visual Appraisal of Colors and ColorDifferences of Diffusely-Illuminated Opaque MaterialsD4086 Practice for Visual Evaluation of MetamerismE284 Terminology of AppearanceE308 Practice for Computing the Colors of Objects by Usingthe CIE SystemE805 Practice for Identification of Instrumental Methods of1This practice is under the jurisdiction of ASTM Committee E12 on Color andAppearance and is the direct responsibility of Subcommittee E12.04 on Color andAppearance Analysis.Current edition approved Oct.1,2022.Published October 2022.Originallyapproved in 1964.Last previous edition approved in 2021 as D2244 21.DOI:10.1520/D2244-22.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1Color or Color-Difference Measurement of MaterialsE1164 Practice for Obtaining Spectrometric Data for Object-Color Evaluation2.2 Other Standards:DIN 6176 English translation of DIN 6176:2018-10 Farb-metrische Bestimmung vo