ASTM D4086-18(2023)

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: D4086 − 18 (Reapproved 2023)
Standard Practice for
Visual Evaluation of Metamerism
This standard is issued under the fixed designation D4086; 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
Because perceived color involves the spectral characteristics of source, object, and eye, different
combinations of spectral characteristics can evoke the same color sensation. For this reason,
metamerism has been described as “invisible spectral differences.”
A pair of specimens is said to be metameric when the specimens match under one set of illuminating
and viewing conditions and do not match under another set. For this condition to exist, there must be
differences in spectral character of specimens and sources or specimens and observers. There may be
more than one condition under which the specimens match, as well as more than one for which they
are a mismatch. Similarly, two specimens may be a near-match under one set of conditions, and under
another set the direction and magnitude of the color difference may change.
1. Scope 2. Referenced Documents
1.1 This practice describes visual methods for detecting 2.1 ASTM Standards:
metamerism and for estimating the magnitude of a metameric D2616 Test Method for Evaluation of Visual Color Differ-
color difference. ence With a Gray Scale
E284 Terminology of Appearance
1.2 The practice is limited to the consideration of illuminant
metamerism and observer metamerism. This practice does not
3. Terminology
cover gonioapparent samples.
3.1 Definitions of appearance terms used in this practice
1.3 This practice does not provide for the computation of
may be found in Terminology E284.
indices of metamerism based upon instrumental measurement
3.2 Definitions:
of spectral characteristics.
3.2.1 metamerism, n—property of two specimens that match
1.4 This standard does not purport to address all of the
under a specified illuminator and to a specified observer and
safety concerns, if any, associated with its use. It is the
whose spectral reflectances or transmittances differ in the
responsibility of the user of this standard to establish appro-
visible wavelengths.
priate safety, health, and environmental practices and deter-
3.2.1.1 Discussion—As a consequence of the required
mine the applicability of regulatory limitations prior to use.
difference, the two specimens may not match under a different
1.5 This international standard was developed in accor-
illuminator or to a different observer. Similar considerations
dance with internationally recognized principles on standard-
apply to two lights matching to a specified observer but not to
ization established in the Decision on Principles for the
other observers. (E284)
Development of International Standards, Guides and Recom-
3.2.2 paramerism, n—phenomenon in which specimens
mendations issued by the World Trade Organization Technical
having different spectrophotometric curves produce approxi-
Barriers to Trade (TBT) Committee.
mately the same color sensation under the same illuminating
and viewing conditions. (E284)
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. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 1, 2023. Published November 2023. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1982. Last previous edition approved in 2018 as D4086 – 18. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D4086-18R23. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4086 − 18 (2023)
4. Significance and Use difference was manifested. Use is made of paired gray scales,
as specified in Test Method D2616, that display increasingly
4.1 Metameric color matches result from the use of different
larger color differences with each successive pair of grays in
colorants (pigments, dyes, and the like) in achieving the same
the scale. The metameric specimen pair is placed in juxtapo-
color match. Usually, the purchaser requires that the color
sition with the edge of the gray scale and compared with
match be nonmetameric; this practice permits this requirement
various gray pairs. The total perceived color difference be-
to be quickly tested in both field and laboratory. Where
tween the two members of the test pair is compared to the
nonmetameric matches are not possible or practicable, for cost
lightness differences of the pairs on the gray scale, and the gray
or other reasons, some limitation of metamerism may be
scale pair is selected that is the best visual equivalent to the
required. The procedures for estimating the magnitude of
color difference of the test pair following the procedures given
metamerism described in this practice provide methods for
in Test Method D2616. It is assumed, as in the Significance and
assessing the effectiveness of such limitation.
Use section in Test Method D2616, that, the total color
difference can be so evaluated in terms of an equivalent
5. Test Speci
...