ASTM E811-95

Standard Practice for Measuring Colorimetric Characteristics of Retroreflectors Under Nighttime Conditions

SCOPE
1.1 This practice describes the instrumental determination of retroreflected chromaticity coordinates of retro- reflectors. It includes the techniques used in a photometric range to measure retroreflected (nighttime) chromaticity with either a telecolorimeter or telespectroradiometer.  
1.2 This practice covers the general measurement procedures. Additional requirements for specific tests and specifications are described in Section 7.  
1.3 The description of the geometry used in the nighttime colorimetry of retroreflectors is described in Practice E808 and the methods for calculation of chromaticity are contained in Test Method E308.  
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: 31-Dec-2000
• Technical Committee: E12 - Color and Appearance
• Drafting Committee: E12.10 - Retroreflection

Relations

• Replaced By: ASTM E811-95(2001) - Standard Practice for Measuring Colorimetric Characteristics of Retroreflectors Under Nighttime Conditions
• Effective Date: 01-Jan-2001

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NOTICE: This standard has either been superseded and replaced by a new version or
withdrawn.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: E 811 – 95
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Practice for
Measuring Colorimetric Characteristics of Retroreflectors
1
Under Nighttime Conditions
This standard is issued under the fixed designation E 811; 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.
1. Scope 3.2.1 chromaticity coordinates, n—the ratios of each of the
tristimulus values of a psychophysical color to the sum of the
1.1 This practice describes the instrumental determination
tristimulus values.
of retroreflected chromaticity coordinates of retroreflectors. It
3.2.1.1 Discussion—Chromaticity coordinates in the CIE
includes the techniques used in a photometric range to measure
1931 system of color specification are designated by x, y, z and
retroreflected (nighttime) chromaticity with either a telecolo-
in the CIE 1964 supplementary system by x , y , z .
10 10 10
rimeter or telespectroradiometer.
3.2.2 CIE 1931 (x, y)-chromaticity diagram—the chroma-
1.2 This practice covers the general measurement proce-
ticity diagram for the CIE 1931 standard observer, in which the
dures. Additional requirements for specific tests and specifica-
CIE 1931 chromaticity coordinates are plotted with x as the
tions are described in Section 7.
abscissa and y as the ordinate.
1.3 The description of the geometry used in the nighttime
3.2.3 CIE 1931 standard observer, n—ideal colorimetric
colorimetry of retroreflectors is described in Practice E 808 and
observer with color matching functions x¯(l), y¯ (l), z¯ (l)
the methods for calculation of chromaticity are contained in
corresponding to a field of view subtending a 2° angle on the
Test Method E 308.
B
4
retina; commonly called the “2° standard observer.” [CIE]
1.4 This standard does not purport to address all of the
3.2.3.1 Discussion—The color matching functions of the
safety concerns, if any, associated with its use. It is the
CIE 1931 standard observer are tabulated in Test Method
responsibility of the user of this standard to establish appro-
E 308, CIE Publication 15.2, and CIE Standard S 002.
priate safety and health practices and determine the applica-
3.2.4 CIE standard illuminant A, n—colorimetric illumi-
bility of regulatory limitations prior to use.
nant, representing the full radiation at 2855.6 K, defined by the
B
2. Referenced Documents CIE in terms of a relative spectral power distribution. [CIE]
3.2.4.1 Discussion—The relative spectral power distribu-
2.1 ASTM Standards:
2
tion of CIE standard illuminant A is tabulated in Test Method
E 284 Terminology of Appearance
E 308, CIE Publication 15.2, and CIE Standard S 001.
E 308 Test Method for Computing the Colors of Objects by
2
3.2.5 CIE standard source A, n—a gas-filled tungsten-
Using the CIE System
2
filament lamp operated at a correlated color temperature of
E 808 Practice for Describing Retroreflection
B
2855.6 K. [CIE]
E 809 Practice for Measuring Photometric Characteristics
2
3.2.6 entrance angle, b, n—in retroreflection, angle be-
of Retroreflectors
tween the illumination axis and the retroreflector axis.
2.2 CIE Documents:
3
3.2.6.1 Discussion—The entrance angle is usually no larger
CIE Publication No. 15.2 Colorimetry, 2d ed.
than 90°, but for completeness its full range is defined as 0° #
CIE Standard S 001/ISO IS 10526, Colorimetric Illumi-
3
b # 180°. To completely specify the orientation, this angle is
nants
3
characterized by two components, b and b .
CIE Standard S 002/ISO IS 10527, Colorimetric Observers 1 2
3.2.7 goniometer, n—an instrument for measuring or setting
3. Terminology
angles.
3.2.8 illumination axis, n—in retroreflection, a line from the
3.1 The terms and definitions in Terminology E 284 apply to
effective center of the source aperture to the retroreflector
this practice.
center.
3.2 Definitions:
3.2.9 observation angle, n—angle between the axes of the
incident beam and the observed (reflected) beam, (in retrore-
1
This practice is under the jurisdiction of ASTM Committee E-12 on Appear-
flection, a, angle between the illumination axis and the
ance and is the direct responsibility of Subcommittee E12.10 on Retroreflection.
observation axis).
Current edition approved March 15, 1995. Published May 1995. Originally
published as E 811 – 81. Last previous edition E 811 – 94a.
2 4
Annual Book of ASTM Standards, Vol 06.01. Stephenson, H. F., “The Colorimetric Measurement of Retroreflective Materi-
3
Available from USNC/CIE Publications Office, % TLA Lighting Consultants, als. Progress Report on Intern
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