ASTM E1347-06(2020)

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.
Designation: E1347 − 06 (Reapproved 2020)
Standard Test Method for
Color and Color-Difference Measurement by Tristimulus
Colorimetry
This standard is issued under the fixed designation E1347; 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.
1. Scope this method yields results that are useful to evaluate and
characterize retroreflective specimens, or specimens having
1.1 This test method covers the instrumental measurement
optical structures.
ofspecimensresultingincolorcoordinatesandcolordifference
values by using a tristimulus colorimeter, also known as a 1.7 This test method does not apply to the use of a
spectrocolorimeter, which is a spectrometer that provides
tristimulus filter colorimeter or a color-difference meter.
colorimetric data, but not the underlying spectral data. Mea-
1.2 Provision is made in this test method for the measure-
surement by using a spectrocolorimeter is covered in Practice
ment of color coordinates and color differences by reflected or
E1164 and methods on color measurement by spectrophotom-
transmitted light using either a hemispherical optical measur-
etry.
ing system, such as an integrating sphere, or a bidirectional
1.8 This standard does not purport to address all of the
optical measuring system, such as annular, circumferential, or
safety concerns, if any, associated with its use. It is the
uniplanar 45:0 and 0:45 geometry.
responsibility of the user of this standard to establish appro-
1.3 Because of the limited absolute accuracy of tristimulus
priate safety, health, and environmental practices and deter-
colorimeters, this test method specifies that, when color coor-
mine the applicability of regulatory limitations prior to use.
dinates are required, the instrument be standardized by use of
1.9 This international standard was developed in accor-
a standard having similar spectral (color) and geometric
dance with internationally recognized principles on standard-
characteristics to those of the specimen. This standard is also
ization established in the Decision on Principles for the
known as a product standard. The use of a product standard of
Development of International Standards, Guides and Recom-
suitable stability is highly desirable.
mendations issued by the World Trade Organization Technical
1.4 Because tristimulus colorimeters do not provide any Barriers to Trade (TBT) Committee.
informationaboutthereflectanceortransmittancecurvesofthe
specimens, they cannot be used to gain any information about 2. Referenced Documents
metamerism or paramerism.
2.1 ASTM Standards:
1.5 Because of the inability of tristimulus (filter) colorim- D2244 Practice for Calculation of Color Tolerances and
eters to detect metamerism or paramerism of specimens, this Color Differences from Instrumentally Measured Color
test method specifies that, when color differences are required, Coordinates
the two specimens must have similar spectral (color) and E179 Guide for Selection of Geometric Conditions for
geometric characteristics. In this case, the instrument may be
Measurement of Reflection and Transmission Properties
standardized for reflectance measurement by use of a white of Materials
reflectance standard or, for transmittance measurement, with
E284 Terminology of Appearance
no specimen or standard at the specimen position. E805 Practice for Identification of Instrumental Methods of
Color or Color-Difference Measurement of Materials
1.6 This test method is generally suitable for any non-
E1164 PracticeforObtainingSpectrometricDataforObject-
fluorescent, planar, object-color specimens of all gloss levels.
Color Evaluation
Users must determine whether an instrument complying with
E1345 Practice for Reducing the Effect of Variability of
Color Measurement by Use of Multiple Measurements
This test method is under the jurisdiction of ASTM Committee E12 on Color
and Appearance and is the direct responsibility of Subcommittee E12.02 on
Spectrophotometry and Colorimetry. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved May 1, 2020. Published May 2020. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1990. Last previous edition approved in 2015 as E1347 – 06 (2015). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/E1347-06R20. the ASTM website.
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E1347 − 06 (2020)
3. Terminology 4.2 This test method includes two different procedures for
standardizing the colorimeter. The first procedure utilizes a
3.1 Definitions:
white standard of known reflectance factor; the second proce-
3.1.1 The definitions contained in Guide E179 and Termi-
dure utilizes a local standard.
nology E284 are applicable to this test method.
4.2.1 When absolute values of color coordinates are to be
determined, the use of a white standard is recommended only
4. Summary of Test Method
with colorimeters in which there is good conformance of the
4.1 This test method provides procedures for measuring
colorimeter readings to CIE tristimulus values, as determined
object-color specimens in either transmission or reflection with
by measurement of suitable verification standards (see Practice
atristimuluscolorimeter(hereafterreferredtoasacolorimeter)
E1164).Withinstrumentsnotmeetingthisrequirement,theuse
by use of the following geometric conditions and standardiza-
of local standards is recommended, but only when the signal
tion procedures:
level (see Note 2) from the use of each colorimeter filter is
4.1.1 Color differences by reflected light of nonmetameric,
adequately high.
nonparameric pairs of opaque or translucent specimens by use
NOTE 1—Of necessity, the above requirements are in part subjective, as
ofeitherhemisphericalgeometry,withanintegratingsphere,or
the methods for verifying conformance to the requirements may not be
bidirectional geometry, such as annular, circumferential, or
available to the average user. Each user must decide whether the
uniplanar 45:0 or 0:45 geometry. The colorimeter may be
standardization procedure selected results in a loss of accuracy in the
standardized by use of a white reflectance standard.
measurements that is negligibly small for the purpose for which data are
obtained.
4.1.2 Color differences by transmitted light of
NOTE 2—The adequacy of the signal level can be determined by
nonmetameric, nonparameric pairs of transparent or translu-
measuring the short-term repeatability without replacement, and ascer-
cent specimens by use of hemispherical geometry. The colo-
taining that the variation in the answer represents less than 30 % of the
rimeter may be standardized by use of a white standard at the
desired or allowable variation.
reflection port of the integrating sphere with no specimen in
4.2.2 When color differences are to be measured, only
place. When translucent specimens are measured, they should
relative measured values are required for the two members of
be placed flush against the transmission port of the sphere, and
the color-difference pair, and standardization by use of either a
the white standard should, for maximum accuracy, have the
white standard or a local standard is satisfactory. In those cases
samereflectanceandchemicalcompositionasthatofthelining
where a computer program is being used to predict color
of the integrating sphere.
tolerances, accuracy of the absolute values of the product
4.1.3 Color coordinates by reflected light of opaque or
standard color coordinates may become more important (see
translucent specimens by use of either bidirectional or hemi-
4.2.1).
spherical geometry. The colorimeter may be standardized by
4.3 Procedures for selecting specimens suitable for preci-
use of a standard having spectral (color) and geometric
sion measurement are included in this test method.
characteristics similar to those of the specimens. Such
standards, often called hitching-post standards, are hereafter
4.4 Most modern colorimeters compute the color coordi-
referred to as local standards.
natesofthespecimenduringthemeasurement.Whenthisisthe
4.1.4 Color coordinates by transmitted light of transparent
case, the user of this test method must designate the color
or translucent specimens by use of hemispherical geometry.
system to be used in the computation (see Practice D2244).
The colorimeter may be standardized by use of a local
standard.
5. Significance and Use
4.1.5 This test method is not appropriate for fluorescent
5.1 The most direct and accessible methods for obtaining
specimens.
the color differences and color coordinates of object colors are
4.1.6 For the measurement of the daytime color of retrore-
by instrumental measurement using colorimeters or spectro-
flective specimens, the 45:0 or 0:45 conditions are normally
photometers with either hemispherical or bidirectional optical
required. Some modern, high brightness, retroreflective sheet-
measuring systems. This test method provides procedures for
ing has been shown to exhibit geometric artifacts if the cone
such measurement by use of a colorimeter with either a
angles are too narrow. In these cases, it may be more
bidirectional or a hemispherical optical measuring system.
appropriate to use larger cone angles, with appropriate toler-
ances. 5.2 This test method is suitable for measurement of color
differences of nonmetameric, nonparameric pairs of object-
4.1.7 When the specimens exhibit directionality, and a
colorimeter with uniplanar bidirectional geometry is used, color specimens, or color coordinates of most such specimens.
A further limitation to the use of colorimeters having hemi-
information on directionality may be obtained by measuring
the specimens at more than one rotation angle, typically at two spherical geometry is the existence of a chromatic integrating-
sphere error that prevents accurate measurement of color
angles 90° apart. When such information is not required, these
measurements may be averaged, or a colorimeter with annular coordinates when the colorimeter is standardized by use of a
white standard.
or circumferential bidirectional geometry may be used.
3 4
Hunter, R. S., “Photoelectric Tristimulus Colorimetry with Three Filters,” Hoffman, K.,“Chromatic Integrating-Sphere Error in Tristimulus
Journal, Optical Society of America, Vol 32, 1942, pp. 509–558. Colorimeters,” Journal of Color and Appearance, Vol 1, No. 2, 1971, pp. 16–21.
E1347 − 06 (2020)
5.3 For the measurement of retroreflective specimens by 8. Standardization and Verification
this test method, the use of bidirectional geometry is recom-
8.1 Standardization for the Measurement Color Differences
mended (see Guide E179 and Practice E805).
of Specimen Pairs:
NOTE 3—To ensure inter-instrument agreement in the measurement of 8.1.1 Standardize the colorimeter by use of the white
retroreflective specimens, significantly tighter tolerances than those given
standard (mandatory) and the zero-reading standard (if
in Practice E1164 in the section on Influx and Efflux Conditions for
required), following the manufa
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