ASTM D1729-22

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Designation: D1729 − 16 D1729 − 22
Standard Practice for
Visual Appraisal of Colors and Color Differences of
Diffusely-Illuminated Opaque Materials
This standard is issued under the fixed designation D1729; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
INTRODUCTION
The colors of materials depend on the geometric and spectral nature of the illuminating and viewing
conditions. This practice specifies standard conditions for appraising the colors and color differences
of opaque specimens that are diffusely illuminated. Daylight, the natural illuminant, is usually of
primary interest, but natural daylight is highly variable and is not available at night or in interior
rooms, so simulated daylight is generally used. Colors may match under a light source with one
spectral power distribution, but not under another, so the match is usually confirmed under another
very different source. An incandescent lamp of low correlated color temperature has long been used
to detect mismatches likely to appear under yellower phases of daylight or incandescent light.
Industrial color matchers often verify the match with the kind of light likely to be found where the
product is sold or used. Judgments should be made by observers with superior color vision as rated
with the FM-100 Hue Test. Even so, there may be substantial individual differences in judgments.
1. Scope
1.1 This practice specifies the equipment and procedures for visual appraisal of the colors and color differences of opaque
materials that are diffusely illuminated. These specifications are of critical importance in color matching. This practice requires
judgments by observers with a minimum of normal color vision and preferably superior as rated with the FM-100 Hue Test as
specified in Guide E1499.
1.2 Critical visual appraisal of colors and color differences of materials such as metallic and pearlescent paints requires
illumination that is nearly a geometric simulation of direct sunlight, because such directional illumination permits observation of
the sparkle (glitter) and goniochromatism that characterize such materials. Such viewing conditions are beyond the scope of this
practice.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 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.
This practice 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 Jan. 1, 2016June 1, 2022. Published February 2016June 2022. Originally approved in 1960. Last previous edition approved in 20092016 as
D1729 – 96 (2009).D1729 – 16. DOI: 10.1520/D1729-16.10.1520/D1729-22.
This standard has been approved for use by agencies of the Department of Defense to replace Method 4249.1 of Federal Test Method Standard No 141. Consult the DoD
Index of Specifications and Standards for the specific year of issue which has been adopted by the Department of Defense.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1729 − 22
1.5 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:
D523 Test Method for Specular Gloss
D1535 Practice for Specifying Color by the Munsell System
D4086 Practice for Visual Evaluation of Metamerism
D5531 Guide for Preparation, Maintenance, and Distribution of Physical Product Standards for Color and Geometric
Appearance of Coatings
E284 Terminology of Appearance
E308 Practice for Computing the Colors of Objects by Using the CIE System
E1164 Practice for Obtaining Spectrometric Data for Object-Color Evaluation
E1499 Guide for Selection, Evaluation, and Training of Observers
2.2 ISO/CIE Standard:Standards:
CIE 015:2018 Colorimetry
ISO 1052611664-2:2007 CIE Standard Colorimetric Illuminants (1991)Colorimetry — Part 2: CIE standard illuminants
ISO 3664-2009 Graphic Technology and photography—Viewing conditions
3. Terminology
3.1 For definitions of appearance terms used in this practice, refer to Terminology E284.
4. Significance and Use
4.1 Although color measuring instruments are widely used, color matches are usually checked visually. The standardization of
visual examination has greatly improved the uniformity of products and the accuracy of color matches.
4.2 The use of this practice is essential for critical color matching but is also recommended for any color appraisal, such as the
choice or approval of a color. This practice is widely used in industry to choose colors, exhibit colors reproducibility, inspect
incoming materials, monitor color producing processes, and inspect finished goods. Visual appraisal is particularly important when
the product inspected is not of the same material as the color standard to which it is compared.
4.2.1 Observers—This practice is based on the fundamental assumption that the observer has superior color vision and is trained
and experienced in observing and classifying color differences. The significance of the results depends on that being so. The
selection, evaluation, and training of observers are treated in Guide E1499.
4.2.2 Illumination—Simulated average daylight, D65, is recommended by the International Commission on Illumination (CIE).
D50 is recommended for applications involving color photography or color printing as specified in ISO 3364-2009.
5. Observers
5.1 The validity of the results obtained by this practice depends on visual judgments by an observer or observers having superior
color vision. Even among normal observers, there may be substantial individual variations. Color specifications dependent on this
practice may require averaging the results obtained by a specified number of observers. The nature of an observer’s color vision
can be ascertained by visual tests. Observers should be tested periodically, because an individual’s color vision can change (see
Guide E1499).
6. Apparatus
6.1 The apparatus shall consist of luminaires or viewing booth, specimen table, surround, and ambient field having the following
spectral, photometric, and geometric characteristics:
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.
Available from U.S. National Committee of the CIE (International Commission on Illumination), C/o Thomas M. Lemons, TLA-Lighting Consultants, Inc., 7 Pond St.,
Salem, MA 01970, http://www.cie-usnc.org.
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6.1.1 Spectral Power Distribution—The spectral power distribution of the radiant flux incident on the specimens depends not only
on the source used, but on the nature of any diffuser employed and any reflecting surfaces, including those in the ambient field,
that reflect flux to the specimens.
6.1.1.1 Daylight illumination illumination, as typically provided by wide band, multi-phosphor, linear, fluorescent lamps, shall be
a spectral simulation of daylight of one or more of the following two kinds: average daylight, designated CIE Illuminant D ; or,
for applications involving color photography or color printing, CIE Illuminant D . The spectra of these illuminants are specified
in Practice E308 and CIE Publication 15:2004. The quality of the simulation of daylight shall be assessed by the method specified
in the latest revision of ISO/CIE 23603:2005, previously designated as Publication 51.23603:2005. For critical appraisal of colors
and color differences, the category determined by that method shall be BC(CIELAB) or better. This rating ensures that the source
provides ultraviolet and visible power in the right proportions to make both nonfluorescent and fluorescent materials look very
nearly the way they would in the corresponding phase of natural daylight. LED lamps may be used as daylight simulators provided
they meet the spectral qualities as specified. Users of this practice should be aware of the fact that neither correlated color
temperature nor chromaticity alone qualifies simulated daylight for this purpose.
6.1.1.2 Incandescent illumination shall have the spectral quality of the light from an incandescent lamp commonly used for home
and business lighting, approximately simulating CIE Illuminant A, specified in Practice E308 and ISO/CIE 10526.ISO
11664-2:2007. Due to reduced availability of incandescent lamps, LED lamps may be substituted for incandescent representing
current lamps in use for home and business lighting, provided they are approximately equal in correlated color temperature and
spectral characteristics.
6.1.1.3 Incandescent illumination of low correlated color temperature shall have spectral quality similar to that of a Planckian
radiator having a color temperature of 2300 K. This source is referred to as “Horizon Daylight” because it simulates the spectra
of early morning sunrise and late day sunset. This light is commonly produced by incandescent lamps operated at half their rated
voltage. Due to red
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