ASTM_D_2244_-_16.pdf

Designation:D224416Standard 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 two of the color difference equations from the 1993 version in an informative appendix forhistorical purposes.1.Scope*1.1 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 DIN99 color difference formula givenin DIN 6176(4),or the new 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 and health practices and determine the applica-bility of regulatory requirements prior to use.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 ofColor or Color-Difference Measurement of MaterialsE1164 Practice for Obtaining Spectrometric Data for Object-Color Evaluation1This 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 July 1,2016.Published July 2016.Originally approvedin 1964.Last previous edition approved in 2015 as D2244 15a.DOI:10.1520/D2244-16.2The 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 2.2 Other Standards:DIN 6176 Farbmetrische,Bestimmung von Farbabstndenbei Krperfarben nach der DIN99-Formel43.Terminology3.1 Terms and definitions in Terminology E284 are appli-cable to this practice.3.2 Definitions of Terms Specific to This Standard:3.2.1 colorimetric spectrometer,nspectrometer,one com-ponent of which is a dispersive element(such as a prism,grating or interference filter or wedge or tunable or discreteseries of monochromatic sources),that is normally capable ofproducing as output colorimetric data(such as tristimulusvalues and derived color coordinates or indices of appearanceattributes).Additionally,the colorimetric spectrometer mayalso be able to