ASTM E179-96(2003)
(Guide)Standard Guide for Selection of Geometric Conditions for Measurement of Reflection and Transmission Properties of Materials (Withdrawn 2012)
Standard Guide for Selection of Geometric Conditions for Measurement of Reflection and Transmission Properties of Materials (Withdrawn 2012)
ABSTRACT
This guide is intended for use in selecting terminology, measurement scales, and instrumentation for describing or evaluating such appearance characteristics as glossiness, opacity, lightness, transparency, and haziness in terms of reflected or transmitted light. This guide does not consider the spectral variations responsible for color, but the geometric variables described herein can importantly affect instrumentally measured values of color. This guide deals with the reflected and transmitted light and the selection of geometric conditions for its measurement. There are five kinds of measurement scale used in this guide. First is the regular scale which indicates that only light that has been reflected or transmitted without scattering or diffusion is included for measurement. Second is the specular scale which indicates that only the light that is mirror reflected is included for measurement. The third scale is the diffuse scale which indicates that only the light reflected or transmitted in directions other than the specular or regular direction is included in the measurement. The total scale, the fourth scale, indicates that the light reflected or transmitted in all directions is included for measurement. Last is the directional scale which indicates that the light reflected or transmitted in specified directions only is included for measurement. Directional values depend on the illumination and viewing angles and refer to light reflected or transmitted in directions that differ moderately from the centroid direction or axis of the beam. There should be only one aperture stop in any instrument. This stop determines the cross-sectional area of the incident beam on the specimen. All incident rays within the limits of the illuminator aperture angle, and all rays within the receiver aperture angle, should reach the receiver and be given equal weight by the measurement system. When vignetting occurs, the illumination, viewing, and aperture angles do not adequately describe the geometric properties of the instrument. Regularly and diffusely reflected and transmitted light are often not adequately differentiated and identified to enable their separation for measurement. Most objects and material distribute some light both regularly and diffusely; consequently the regular and diffuse components of reflection and transmission cannot be separated precisely for measurement.
SCOPE
1.1 This guide is intended for use in selecting terminology, measurement scales, and instrumentation for describing or evaluating such appearance characteristics as glossiness, opacity, lightness, transparency, and haziness in terms of reflected or transmitted light. This guide does not consider the spectral variations responsible for color, but the geometric variables described herein can importantly affect instrumentally measured values of color. This guide is general in scope rather than specific as to instrument or material.
WITHDRAWN RATIONALE
This guide is intended for use in selecting terminology, measurement scales, and instrumentation for describing or evaluating such appearance characteristics as glossiness, opacity, lightness, transparency, and haziness in terms of reflected or transmitted light. This guide does not consider the spectral variations responsible for color, but the geometric variables described herein can importantly affect instrumentally measured values of color. This guide is general in scope rather than specific as to instrument or material.
Formerly under the jurisdiction of Committee E12 on Color and Appearance, this guide was withdrawn in April 2012 in accordance with section 10.5.3.1 of the Regulations Governing ASTM Technical Committees, which requires that standards shall be updated by the end of the eighth year since the last approval date.
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Designation: E179 – 96 (Reapproved 2003)
Standard Guide for
Selection of Geometric Conditions for Measurement of
Reflection and Transmission Properties of Materials
This standard is issued under the fixed designation E179; 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
This is a guide describing the selecting of geometric conditions of measurement of appearance
attributes such as color, gloss, reflectance, opacity, and transmittance. It includes a selection of
numerical scales for appearance attributes other than color.
In describing appearance, wavelength (or spectral) variability is primarily responsible for color,
while geometric (or directional) selectivity is primarily responsible for gloss, luster, translucency, and
like attributes. However, geometric conditions not only affect geometric variables such as gloss and
transparency, but also affect color, diffuse reflectance, and transmittance. Likewise spectral conditions
can affect the measurement of geometric attributes of appearance. Therefore both the spectral and
geometric conditions of measurement must be identified in specifying an appearance attribute of a
specimen.
This guide describes the selection of geometric conditions and as a consequence should help
improve agreement in these measurements as well as providing useful guidance in resolving
differences between spectral-type measurements that are related to geometry.
1. Scope C523 Test Method for Light Reflectance of Acoustical
Materials by the Integrating Sphere Reflectometer
1.1 This guide is intended for use in selecting terminology,
C584 Test Method for Specular Gloss of Glazed Ceramic
measurement scales, and instrumentation for describing or
Whitewares and Related Products
evaluating such appearance characteristics as glossiness, opac-
D523 Test Method for Specular Gloss
ity, lightness, transparency, and haziness in terms of reflected
D1003 Test Method for Haze and Luminous Transmittance
or transmitted light. This guide does not consider the spectral
of Transparent Plastics
variations responsible for color, but the geometric variables
D1455 Test Method for 60° Specular Gloss of Emulsion
described herein can importantly affect instrumentally mea-
Floor Polish
sured values of color.This guide is general in scope rather than
D1494 Test Method for Diffuse Light Transmission Factor
specific as to instrument or material.
of Reinforced Plastics Panels
2. Referenced Documents
D1746 Test Method for Transparency of Plastic Sheeting
D1834 Test Method for 20° Specular Gloss of Waxed
2.1 ASTM Standards:
Paper
C346 Test Method for 45-deg Specular Gloss of Ceramic
D4039 Test Method for Reflection Haze of High-Gloss
Materials
Surfaces
C347 Test Method for Reflectance, Reflectivity, and Coef-
D4061 Test Method for Retroreflectance of Horizontal
ficient of Scatter of White Porcelain Enamels
Coatings
E97 Test Method for Directional Reflectance Factor, 45-
This guide is under the jurisdiction of ASTM Committee E12 on Color and
deg, 0-deg, of Opaque Specimens by Broad-Band Filter
Appearance and is the direct responsibility of Subcommittee E12.03 on Geometry.
Reflectometry
Current edition approved Jan. 10, 2003. Published March 2003. Originally
E167 Practice for Goniophotometry of Objects and Materi-
approved in 1961. Last previous edition approved in 1996 as E179 – 96. DOI:
10.1520/E0179-96R03.
als
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Withdrawn. The last approved version of this historical standard is referenced
on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E179 – 96 (2003)
E284 Terminology of Appearance 4. Summary of Guide
E429 Test Method for Measurement and Calculation of
4.1 When light impinges upon a material, several phenom-
Reflecting Characteristics of Metallic Surfaces Using Inte-
ena can occur. Part of the light may be reflected, part may be
grating Sphere Instruments
transmitted, and part may be absorbed. This guide deals with
E430 Test Methods for Measurement of Gloss of High-
the reflected and transmitted light and the selection of geomet-
Gloss Surfaces by Abridged Goniophotometry
ric conditions for its measurement.
E808 Practice for Describing Retroreflection
4.2 An idealization of the light reflected and transmitted by
E809 Practice for Measuring Photometric Characteristics of
a material is shown in Fig. 1. Fig. 2 illustrates luminance
Retroreflectors
distributions more like those actually encountered in practice.
E810 Test Method for Coefficient of Retroreflection of
5. Types of Measurement Scales
Retroreflective Sheeting Utilizing the Coplanar Geometry
E811 Practice for Measuring Colorimetric Characteristics 5.1 Type of Scale—The terms defined in 3.1.6-3.1.8 to may
of Retroreflectors Under Nighttime Conditions
be further identified by a preceding adjective, such as specular,
E991 Practice for Color Measurement of Fluorescent Speci- regular, diffuse, total, or directional, thereby identifying the
mens Using the One-Monochromator Method
basis for the measurement scale. The significance of each of
E1164 Practice for Obtaining Spectrometric Data for
these adjectives is as follows:
Object-Color Evaluation
5.1.1 regular—indicates that only light that has been re-
E1767 Practice for Specifying the Geometries of Observa-
flectedortransmittedwithoutscatteringordiffusionisincluded
tion and Measurement to Characterize the Appearance of
for measurement. When a specimen scatters or diffuses the
Materials
incident light on reflection or transmission, the values obtained
F768 Method for Specular Reflectance and Transmittance
will depend on the angular size of the illuminator and receiver
Measurements of Optically Flat-Coated and Non-Coated
used in the measurement.
Specimens
5.1.2 specular—indicates that only the light that is mirror-
2.2 CIE Publications:
reflected is included for measurement. The CIE prefers the
CIE Publication No. 15.2 Colorimetry, second edition 1986
modifier regular instead of specular although specular reflec-
CIEPublicationNo.17.4 InternationalLightingVocabulary,
tance is recognized. Specular has also sometimes been used to
fourth edition, 1987
refer to regular transmittance. This is a misnomer because
CIE Publication No. 38 Radiometric and Photometric Char-
specular refers to a mirror.
acteristics of Materials and Their Measurement, 1977
5.1.3 diffuse—indicates that only the light reflected or
transmitted in directions other than the specular or regular
3. Terminology
direction is included in the measurement.
3.1 Definitions:
NOTE 1—The differences between the concepts of regular and diffuse
3.1.1 flux (radiant), F—the time rate of flow of radiant
components of reflection and transmission are shown in Table 1.
energy; radiant power (Terminology E284).
5.1.4 total—indicates that the light reflected or transmitted
3.1.2 incident flux, F—flux incident on the specimen at a
i
in all directions is included for measurement.
specified illumination angle and aperture angle.
5.1.5 directional—indicates that the light reflected or trans-
3.1.3 reflected flux, F —flux reflected from the specimen at
r
mitted in specified directions only is included for measure-
a specified viewing angle and aperature angle.
ment. Directional values depend on the illumination and
3.1.4 reference reflected flux, F —flux reflected from a
r.r
viewing angles and refer to light reflected or transmitted in
referencestandardofreflectance,illuminatedandviewedinthe
directions that differ moderately from the centroid direction or
same manner as the specimen under consideration.
axis of the beam.
3.1.5 transmitted flux, F—flux transmitted through the
t
specimen at a specified viewing angle and field angle.
6. Geometric Directions of Incidence and Viewing
3.1.6 reflectance, r—ratio of the reflected flux to the inci-
6.1 Geometric directions may be identified by preceding the
dent flux defined as r = F / F.
r i
adjective with the angular directions, by including a detailed
3.1.7 reflectance factor, R—ratio of the reflected flux to the
reference reflected flux defined asR= F / F .
r r.r
3.1.8 transmittance, t—ratio of the transmitted flux to the
incident flux defined as t = F/ F.
t i
3.1.8.1 Discussion—A companion term, transmittance fac-
tor, is not normally used in the measurement of appearance
attributes.
3.1.9 For other definitions see Terminology E284 and CIE
Publication Nos. 17.4 and 38.
Information on how to obtain CIE documents should be requested from the
U.S. National Committee, CIE, c/o Radiometric Physics Division, National Institute FIG. 1 Idealizations of Reflection and Transmission Phenomena,
of Standards and Technology, Bldg. 220, Room B-306, Gaithersburg, MD 20899. Showing Components
E179 – 96 (2003)
6.3 aperture angles—the angles subtended at a point on the
specimen by the maximum dimension of the apparent illumi-
nator and receiver. They are a necessary part of the geometric
specification because the finite size of every practical illumi-
nator limits collimation.
6.4 azimuthal angle, h—the angle between the plane con-
taining the illuminator axis and the specimen normal and the
plane containing the receiver axis and the specimen normal.
Unless an azimuthal angle is specified, the illuminator axis, the
specimen normal, and the receiver axis are taken to be in the
same plane.
6.5 rotation angle, ´—theangleindicatingtheorientationof
the test specimen when it is rotated in its own plane. The
orientation of the specimen is considered to be part of the
specimen description in this guide (see 10.2.7).
6.6 Complete geometric specifications are necessary for
measuring such geometrically dependent factors as gloss,
transparency, and haze. For ideally specular or ideally regular
FIG. 2 Representations of Actual Reflection and Transmission
or diffuse reflection or transmission, specification of only the
Phenomena with Mixtures of Components
directions of illumination and view is usually adequate.
7. Measured Quantities
TABLE 1 Differences Between Concepts of Regular (Specular)
and Diffuse Components of Reflection and Transmission
7.1 The following quantities, defined and described in more
Resulting
de
...
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