1、Designation:D261612Standard 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
2、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 wa
3、s 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(I
4、nternational 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 rated according to which of nine gray pairs of differences is visually closest to thetest pair,or by
5、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 c
6、oncerns,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 limitations prior to use.2.Referenced Documents2.1 ASTM Standards:3E284 Terminology of AppearanceE1729 Prac
7、tice for Field Collection of Dried Paint Samplesfor Subsequent Lead DeterminationE1499 Guide for Selection,Evaluation,and Training ofObservers2.2 AATCC Procedures:AATCC Evaluation Procedure 1 Gray Scale for ColorChange23.Terminology3.1 Definitions:3.1.1 Definitions of appearance terms in Terminology
8、 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 progressivelylight
9、er,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.NOTE1The gray spe
10、cimen common to each pair is specified to haveCIE 1976 metric lightness,L*=41.2(+0.6,0.60).5.Significance and Use5.1 The total perceived color difference between two non-self luminous specimens is compared as an equivalent lightnessdifference between two neutral gray specimens on a gray scale.A fund
11、amental assumption is made that the total color differ-ence can be so evaluated in terms of an equivalent lightnessdifference.Only the total color differences,that is,a summationof the differences in hue,lightness,and chroma between twospecimens is evaluated;this test method is not applicable to the
12、1This 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 July 1,2012.Published September 2012.Originallyapproved in 1967.Last previous edition approved in 2003 as D2616 9
13、6(2003)which was withdrawn April 2012 and reinstated in July 2012.DOI:10.1520/D261612.2Technical Manual of the American Association of Textile Chemists andColorists,P.O.Box 12215,Research Triangle Park,NC 27709,Vol 86,2011,pp.365366.3For referenced ASTM standards,visit the ASTM website,www.astm.org,
14、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 States1 separate precise evalua
15、tion of the hue,lightness,and chromacomponents 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 colordifference between specimens having rough or mottled sur
16、-faces appears smaller than it would if the specimens hadsmooth and uniform surfaces.Thus the equivalent CIELABlightness difference determined for non-uniform specimenswill be smaller than for uniform specimens.Likewise,speci-mens whose dividing line is not sharp will appear to havesmaller color differences than those with sharp dividing lines,and for this reason,the equivalent visually observed CIELABlightness differences will be smaller than the color differencesobtained from instrumental meas
