ASTM D1729-96(2003)

Standard Practice for Visual Appraisal of Colors and Color Differences of Diffusely-Illuminated Opaque Materials

SIGNIFICANCE AND USE
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.
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 reproducibly, 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 normal 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 E 1499.
4.2.2 Illumination—Simulated average daylight is recommended by the International Commission on Illumination (CIE), but a slightly bluer simulated north-sky daylight came into widespread use in North America, because it provides a slightly greater distinction between very pale yellow and white, a distinction of great commercial importance.
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 specification are of critical importance in color matching. This practice requires judgments by observers with normal color vision.
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 sunlight, because such directional illumination permits observation of the 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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 30-Nov-2003
• ICS: 17.180.20 - Colours and measurement of light
• Technical Committee: E12 - Color and Appearance
• Drafting Committee: E12.11 - Visual Methods

Relations

• Replaces: ASTM D1729-96 - Standard Practice for Visual Appraisal of Colors and Color Differences of Diffusely-Illuminated Opaque Materials
• Effective Date: 01-Dec-2003
• Replaced By: ASTM D1729-96(2009) - Standard Practice for Visual Appraisal of Colors and Color Differences of Diffusely-Illuminated Opaque Materials
• Effective Date: 01-Dec-2009
• Referred By: ASTM E1499-16(2023) - Standard Guide for Selection, Evaluation, and Training of Observers
• Effective Date: 01-Dec-2003
• Referred By: ASTM D822/D822M-13(2018) - Standard Practice for Filtered Open-Flame Carbon-Arc Exposures of Paint and Related Coatings
• Effective Date: 01-Dec-2003
• Referred By: ASTM F940-99(2019)e1 - Standard Practice for Quality Control Receipt Inspection Procedures for Protective Coatings (Paint), Used in Marine Construction and Shipbuilding
• Effective Date: 01-Dec-2003
• Referred By: ASTM D2205-20 - Standard Guide for Selection of Tests for Traffic Paints
• Effective Date: 01-Dec-2003
• Referred By: ASTM D1562-22 - Standard Classification System and Basis for Specification for Cellulose Acetate Propionate Molding and Extrusion Compounds (CAP)
• Effective Date: 01-Dec-2003
• Referred By: ASTM D3451-06(2017) - Standard Guide for Testing Coating Powders and Powder Coatings
• Effective Date: 01-Dec-2003
• Referred By: ASTM D3134-15(2019) - Standard Practice for Establishing Color and Gloss Tolerances
• Effective Date: 01-Dec-2003
• Referred By: ASTM D707-15(2023) - Standard Classification System and Basis for Specification for Cellulose Acetate Butyrate Molding and Extrusion Compounds (CAB)
• Effective Date: 01-Dec-2003
• Referred By: ASTM F29-97(2022) - Standard Specification for Dumet Wire for Glass-to-Metal Seal Applications
• Effective Date: 01-Dec-2003
• Referred By: ASTM D706-20 - Standard Classification System and Basis for Specifications for Cellulose Acetate Molding and Extrusion Compounds (CA)
• Effective Date: 01-Dec-2003
• Referred By: ASTM D3361/D3361M-22 - Standard Practice for Unfiltered Open-Flame Carbon-Arc Exposures of Paint and Related Coatings
• Effective Date: 01-Dec-2003
• Referred By: ASTM D4674-19 - Standard Practice for Accelerated Testing for Color Stability of Plastics Exposed to Indoor Office Environments
• Effective Date: 01-Dec-2003
• Referred By: ASTM E1360-05(2019) - Standard Practice for Specifying Color by Using the Optical Society of America Uniform Color Scales System
• Effective Date: 01-Dec-2003

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information.
Designation:D1729–96(Reapproved2003)
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 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
productissoldorused.Judgmentsmustbemadebyobserverswithnormalcolorvision.Evenso,there
may be substantial individual differences in judgments.
1. Scope responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
1.1 This practice specifies the equipment and procedures for
bility of regulatory limitations prior to use.
visual appraisal of the colors and color differences of opaque
materials that are diffusely illuminated. These specification are
2. Referenced Documents
of critical importance in color matching. This practice requires
2.1 ASTM Standards:
judgments by observers with normal color vision.
D523 Test Method for Specular Gloss
1.2 Critical visual appraisal of colors and color differences
D1535 PracticeforSpecifyingColorbytheMunsellSystem
of materials such as metallic and pearlescent paints requires
D4086 Practice for Visual Evaluation of Metamerism
illumination that is nearly a geometric simulation of sunlight,
D5531 Guide for Preparation, Maintenance, and Distribu-
because such directional illumination permits observation of
tion of Physical Product Standards for Color and Geomet-
the glitter and goniochromatism that characterize such materi-
ric Appearance of Coatings
als. Such viewing conditions are beyond the scope of this
E284 Terminology of Appearance
practice.
E308 Practice for Computing the Colors of Objects by
1.3 The values stated in SI units are to be regarded as the
Using the CIE System
standard. The values given in parentheses are for information
E1164 Practice for Obtaining Spectrometric Data for
only.
Object-Color Evaluation
1.4 This standard does not purport to address all of the
E1499 Guide for Selection, Evaluation, and Training of
safety concerns, if any, associated with its use. It is the
Observers
2.2 ISO/CIE Standard:
CIE 10526 CIE Standard Colorimetric Illuminants (1991)
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 Dec. 1, 2003. Published December 2003. Originally For referenced ASTM standards, visit the ASTM website, www.astm.org, or
approved in 1960. Last previous edition approved in 1996 as D1729 – 96. DOI: contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
10.1520/D1729-96R03. Standards volume information, refer to the standard’s Document Summary page on
This standard has been approved for use by agencies of the Department of the ASTM website.
Defense to replace Method 4249.1 of Federal Test Method Standard No 141. AvailablefromU.S.NationalCommitteeoftheCIE(InternationalCommission
Consult the DoD Index of Specifications and Standards for the specific year of issue on Illumination), C/o Thomas M. Lemons, TLA-Lighting Consultants, Inc., 7 Pond
which has been adopted by the Department of Defense. St., Salem, MA 01970, http://www.cie-usnc.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D1729–96 (2003)
3. Terminology specified in Practice E308 and CIE Publication 15.2. The
quality of the simulation of daylight shall be assessed by the
3.1 Fordefinitionsofappearancetermsusedinthispractice,
method specified in the latest revision of CIE Publication 51
refer to Terminology E284.
(under revision in 1996). For critical appraisal of colors and
color differences, the category determined by that method shall
4. Significance and Use
be BC(CIELAB) or better. This rating ensures that the source
4.1 Although color measuring instruments are widely used, provides ultraviolet and visible power in the right proportions
color matches are usually checked visually. The standardiza-
to make both nonfluorescent and fluorescent materials look
tion of visual examination has greatly improved the uniformity very nearly the way they would in the corresponding phase of
of products and the accuracy of color matches.
natural daylight. Users of this practice should be aware of the
fact that neither correlated color temperature nor chromaticity
4.2 The use of this practice is essential for critical color
alone qualifies simulated daylight for this purpose.
matching but is also recommended for any color appraisal,
6.1.1.2 Incandescent illumination shall have the spectral
such as the choice or approval of a color. This practice is
quality of the light from an incandescent lamp commonly used
widely used in industry to choose colors, exhibit colors
for home and business lighting, approximately simulating CIE
reproducibly, inspect incoming materials, monitor color pro-
Illuminant A, specified in Practice E308 and ISO/CIE 10526.
ducing processes, and inspect finished goods. Visual appraisal
6.1.1.3 Incandescent illumination of low correlated color
is particularly important when the product inspected is not of
temperature shall have spectral quality similar to that of a
thesamematerialasthecolorstandardtowhichitiscompared.
Planckian radiator having a color temperature of 2300 K. This
4.2.1 Observers—This practice is based on the fundamental
light is commonly produced by incandescent lamps operated at
assumption that the observer has normal color vision and is
half their rated voltage.
trained and experienced in observing and classifying color
6.1.1.4 Fluorescent lamps are often provided. Those most
differences. The significance of the results depends on that
often used are of the type known as “cool white” approxi-
being so. The selection, evaluation, and training of observers
mately simulated by CIE Illuminant F2, and the type known as
are treated in Guide E1499.
“three-band” approximately simulated by CIE Illuminant F11.
4.2.2 Illumination—Simulated average daylight is recom-
The spectra of these illuminants are specified in Practice E308
mended by the International Commission on Illumination
and ISO/CIE 10526.
(CIE), but a slightly bluer simulated north-sky daylight came
6.1.1.5 One or several of these kinds of illumination, or
into widespread use in North America, because it provides a
other kinds, as specified, may be provided in a luminaire or
slightlygreaterdistinctionbetweenverypaleyellowandwhite,
viewing booth. Provision must be made for selecting any one
a distinction of great commercial importance.
of the sources independently.
6.1.2 Photometric Conditions—For critical evaluation of
5. Observers
color differences of materials of medium lightness, the illumi-
5.1 The validity of the results obtained by this practice nation at the center of the viewed area shall be 1080 to 1340 lx
(100 to 125 fc). For general evaluation of materials of medium
depends on visual judgments by an observer or observers with
normal color vision. Even among normal observers, there may lightness, the illumination shall be between 810 and 1880 lx
(75and175fc).Ineithercase,forviewingverylightmaterials,
be substantial individual variations. Color specifications de-
pendent on this practice may require averaging the results the illumination may be as low as 540 lx (50 fc), and for
viewing very dark materials it may be as high as 2150 lx (200
obtained by a specified number of observers. The nature of an
observer’s color vision can be ascertained by visual tests. fc). This higher level of illumination is usually obtained by
holding the specimens nearer the source.
Observers should be tested periodically, because an individu-
al’s color vision can change (see Guide E1499). 6.1.3 GeometricConditions—The illumination shall be pro-
vided by an extended-area source located above the specimens
and sh
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