ASTM D2616-19

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Designation: D2616 − 12 D2616 − 19
Standard Test Method for
Evaluation of Visual Color Difference With a Gray Scale
This standard is issued under the fixed designation D2616; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
This test method was developed to provide a precise procedure for visually evaluating color
difference of non-self luminous specimens. It was patterned after a method standardized by the
American Association of Textile Chemists and Colorists (AATCC) designed to evaluate “change in
color” and this antecedent was reflected in the original title.
This test method provides for evaluation of small to moderate color differences (less than 15
CIELAB (International Commission on Illumination) color difference units) by comparing test
specimens to a series of paired gray color chips having progressively larger lightness differences.
Color difference is ratedevaluated according to which of nine gray pairs of differences is visually
closest to the test pair, or by interpolation between gray-pair differences.
1. Scope
1.1 This test method describes a painted gray scale and the procedure to be used in the visual evaluation of color differences
of non-self luminous materials by comparison to this scale.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.3 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D1729 Practice for Visual Appraisal of Colors and Color Differences of Diffusely-Illuminated Opaque Materials
E284 Terminology of Appearance
E1729 Practice for Field Collection of Dried Paint Samples for Subsequent Lead Determination
E1499 Guide for Selection, Evaluation, and Training of Observers
E3040 Practice for Evaluation of Instrumental Color Difference with a Gray Scale
2.2 AATCC Procedures:
AATCC Evaluation Procedure 1 Gray Scale for Color Change
3. Terminology
3.1 Definitions:
3.1.1 Definitions of appearance terms in Terminology E284 are applicable to this test method.
4. Summary of Test Method
4.1 The gray scale consists of nine pairs of neutral gray color standards of which Reference Pair 5 is two examples of the same
gray. One element common to each pair is the gray of Reference Pair 5; the other element, being progressively lighter, provides
This test method is under the jurisdiction of ASTM Committee E12 on Color and Appearance and is the direct responsibility of Subcommittee E12.11 on Visual Methods.
Current edition approved July 1, 2012Nov. 1, 2019. Published September 2012November 2019. Originally approved in 1967. Last previous edition approved in 20032012
as D2616D2616 – 12. – 96 (2003) which was withdrawn April 2012 and reinstated in July 2012. DOI: 10.1520/D2616–12.DOI: 10.1520/D2616-19.
Technical Manual of the American Association of Textile Chemists and Colorists, P.O. Box 12215, Research Triangle Park, NC 27709, Vol 27709.86, 2011, pp. 365–366.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2616 − 19
a succession of lightness differences. Total color differences between non-self luminous non-self-luminous specimens are
expressed as either fractional, linear scale value between 1 and 5 by comparison with the paired differences of the gray scale, which
are predominantly lightness differences.
NOTE 1—The gray specimen common to each pair is specified to have CIE 1976 metric lightness, L* = 41.2 (+ 0.6, − 0.60).
5. Significance and Use
5.1 The total perceived color difference between two non-self luminous non-self-luminous specimens is compared as an
equivalent lightness difference between two neutral gray specimens on a gray scale. A fundamental assumption is made that the
total color difference can be so evaluated in terms of an equivalent lightness difference. Only the total color differences, that is,
a summation of the differences in hue, lightness, and chroma between two specimens is evaluated; this test method is not applicable
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 method depends on the degree of uniformity of the specimens and on the
sharpness of the dividing line between them. The color difference between specimens having rough or mottled surfaces appears
smaller than it would if the specimens had smooth and uniform surfaces. Thus the equivalent CIELAB lightness difference
determined for non-uniform specimens will be smaller than for uniform specimens. Likewise, specimens whose dividing line is
not sharp will appear to have smaller color differences than those with sharp dividing lines, and for this reason, the equivalent
visually observed CIELAB lightness differences will be smaller than the color differences obtained from instrumental
measurements.
5.2.1 A physically sharp border between colors differing slightly in the yellow-blue direction in color space appears diffuse. The
perceived color difference is noticeably increased by a hairline black separation. This technique imposes a more rigorous test of
such small differences.
5.3 In the CIELAB system, a unit of color difference is intended to represent the same visual difference in each of the three
attributes; lightness, hue and chroma or alternatively lightness, redness-greeness,redness-greenness, yellowness-blueness. It is
valid to express color differences that are not simply lightness differences by comparison to a lightness-difference scale.
5.4 Personnel to be employed in the evaluation of color differences with the paired gray scale should be tested for color vision
using the procedures in Guide E1499.
6. Apparatus
6.1 Gray Scale Chart, having having the characteristics as shown in Table 1X1.1 in Appendix X1. The DE* values in this table
are only for the purpose of determining if the Gray Scale Chart itself meets performance specifications. It is not to be used to
convert either visual ratings to DE* values or DE* values to Gray Scale ratings.
NOTE 1—It should be recognized that the practical requirements of gray scale production mitigate against members of a reference pair either being
absolutely neutral, or being of identical near-neutral chromaticity. However, chromaticity differences, if present, are of negligible magnitude.
6.2 Gray Masks—Light gray masks with rectangular openings shall be used
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