ASTM_D_2616_-_19.pdf

Designation:D261619Standard Test Method forEvaluation of Visual Color Difference With a Gray Scale1This standard is issued under the fixed designation D2616;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.INTRODUCTIONThis test method was developed to provide a precise procedure for visually evaluating colordifference of non-self luminous specimens.It was patterned after a method standardized by theAmerican Association of Textile Chemists and Colorists(AATCC)2designed to evaluate“change incolor”and this antecedent was reflected in the original title.This test method provides for evaluation of small to moderate color differences(less than 15CIELAB(International Commission on Illumination)color difference units)by comparing testspecimens to a series of paired gray color chips having progressively larger lightness differences.Color difference is evaluated according to which of nine gray pairs of differences is visually closestto the test pair,or by interpolation between gray-pair differences.1.Scope1.1 This test method describes a painted gray scale and theprocedure to be used in the visual evaluation of color differ-ences of non-self luminous materials by comparison to thisscale.1.2 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.1.3 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 MaterialsE284 Terminology of AppearanceE1499 Guide for Selection,Evaluation,and Training ofObserversE3040 Practice for Evaluation of Instrumental Color Differ-ence with a Gray Scale2.2 AATCC Procedures:AATCC Evaluation Procedure 1 Gray Scale for ColorChange23.Terminology3.1 Definitions:3.1.1 Definitions of appearance terms in Terminology E284are applicable to this test method.4.Summary of Test Method4.1 The gray scale consists of nine pairs of neutral graycolor standards of which Reference Pair 5 is two examples ofthe same gray.One element common to each pair is the gray ofReference Pair 5;the other element,being progressivelylighter,provides a succession of lightness differences.Totalcolor differences between non-self-luminous specimens areexpressed as either fractional,linear scale value between 1 and5 by comparison with the paired differences of the gray scale,which are predominantly lightness differences.5.Significance and Use5.1 The total perceived color difference between two non-self-luminous specimens is compared as an equivalent light-ness difference between two neutral gray specimens on a grayscale.A fundamental assumption is made that the total colordifference can be so evaluated in terms of an equivalent1This test method is under the jurisdiction of ASTM Committee E12 on Colorand Appearance and is the direct responsibility of Subcommittee E12.11 on VisualMethods.Current edition approved Nov.1,2019.Published November 2019.Originallyapproved in 1967.Last previous edition approved in 2012 as D2616 12.DOI:10.1520/D2616-19.2Technical Manual of the American Association of Textile Chemists andColorists,P.O.Box 12215,Research Triangle Park,NC 27709.3For 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.1 lightness difference.Only the total color differences,that is,asummation of the differences in hue,lightness,and chromabetween two specimens is evaluated;this test method is notapplicable to the separate precise evaluation of the hue,lightness,and chroma components of color difference.5.2 The total color difference determined by this test methoddepends on the degree of uniformity of the specimens and onthe sharpness of the dividing line between them.The colord