ASTM D4086-92a(1997)e1

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
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e1
Designation: D 4086 – 92a (Reapproved 1997)
Standard Practice for
Visual Evaluation of Metamerism
This standard is issued under the fixed designation D 4086; 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 (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Editorial correction made in Section 3 in September 1997.
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.”
Apairofspecimensissaidtobemetamericwhenthespecimensmatchunderonesetofilluminating
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 E 284 Terminology of Appearance
1.1 This practice describes visual methods for detecting
3. Terminology
metamerism and for estimating the magnitude of a metameric
3.1 Definitions of appearance terms used in this practice
color difference.
may be found in Terminology E 284.
1.2 The practice is limited to the consideration of illuminant
3.2 Definitions:
metamerism and observer metamerism. It is not designed to
3.2.1 metamerism, n—property of two specimens that
cover so-called geometric metamerism, in which members of
match under a specified illuminator and to a specified observer
specimen pairs change relative appearance as the angles of
and whose spectral reflectances or transmittances differ in the
illumination and viewing are changed, for example, because
visible wavelengths.
they incorporate flake metal or pearlescent colorants.
3.2.1.1 Discussion—As a consequence of the required dif-
1.3 This practice does not provide for the computation of
ference, the two specimens may not match under a different
indices of metamerism based upon instrumental measurement
illuminator or to a different observer. Similar considerations
of spectral characteristics.
apply to two lights matching to a specified observer but not to
1.4 This standard does not purport to address all of the
other observers. (E 284)
safety concerns, if any, associated with its use. It is the
3.2.2 paramerism, n—phenomenon in which specimens
responsibility of the user of this standard to establish appro-
having different spectrophotometric curves produce approxi-
priate safety and health practices and determine the applica-
mately the same color sensation under the same illuminating
bility of regulatory limitations prior to use.
and viewing conditions. (E 284)
2. Referenced Documents
4. Significance and Use
2.1 ASTM Standards:
4.1 Metameric color matches result from the use of different
D 2616 Test Method for Evaluation of Visual Color Differ-
2 colorants (pigments, dyes, and the like) in achieving the same
ence With a Gray Scale
color match. Usually, the purchaser requires that the color
match be nonmetameric; this practice permits this requirement
This practice is under the jurisdiction of ASTM Committee E-12 on Appear- to be quickly tested in both field and laboratory. Where
ance and is the direct responsibility of Subcommittee E12.11 on Visual Methods.
nonmetameric matches are not possible or practicable, for cost
Current edition approved May 15, 1992. Published September 1992. Originally
or other reasons, some limitation of metamerism may be
published as D 4086 – 82. Last previous edition D 4086 – 92.
required. The procedures for estimating the magnitude of
Annual Book of ASTM Standards, Vol 06.01.
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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.
D 4086
metamerism described in this practice provide methods for D 2616, Section 5.1 that, the total color difference can be so
assessing the effectiveness of such limitation. evaluated in terms of an equivalent lightness difference.
Observers can be expected to reproduce such evaluations
5. Test Specimens
within a half-step
...