ASTM E430-23

Standard Test Methods for Measurement of Gloss of High-Gloss Surfaces by Abridged Goniophotometry

SIGNIFICANCE AND USE
5.1 The gloss of metallic finishes is important commercially on metals for automotive, architectural, and other uses where these metals undergo special finishing processes to produce the appearances desired. It is important for the end-products, which use such finished metals that parts placed together have the same glossy appearance.  
5.2 It is also important that automotive finishes and other high-gloss nonmetallic surfaces possess the desired finished appearance. The present method identifies by measurements important aspects of finishes. Those having identical sets of numbers normally have the same gloss characteristics. It usually requires more than one measurement to identify properly the glossy appearance of any finish (see Refs 3 and 4).
SCOPE
1.1 These test methods cover the measurement of the reflection characteristics responsible for the glossy appearance of high-gloss surfaces. Two test methods, A and B, are provided for evaluating such surface characteristics at specular angles of 20° and 30°, respectively. These test methods are not suitable for diffuse finish surfaces nor do they measure color, another appearance attribute.  
1.2 As originally developed by Tingle and others (see Refs 1 and 2),2 the test methods were applied only to bright metals. Recently they have been applied to high-gloss automotive finishes and other nonmetallic surfaces.  
1.3 The DOI of a glossy surface is generally independent of its curvature. The DOI measurement by this test method is limited to flat or flattenable surfaces.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 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.

General Information

• Status: Published
• Publication Date: 31-May-2023
• ICS: 17.040.20 - Properties of surfaces
• Technical Committee: E12 - Color and Appearance
• Drafting Committee: E12.03 - Geometry

Relations

• Refers: ASTM E1347-06(2020) - Standard Test Method for Color and Color-Difference Measurement by Tristimulus Colorimetry
• Effective Date: 01-May-2020
• Refers: ASTM E308-17 - Standard Practice for Computing the Colors of Objects by Using the CIE System
• Effective Date: 01-May-2017
• Refers: ASTM E1347-06(2015) - Standard Test Method for Color and Color-Difference Measurement by Tristimulus Colorimetry
• Effective Date: 01-Nov-2015
• Refers: ASTM E308-15 - Standard Practice for Computing the Colors of Objects by Using the CIE System
• Effective Date: 01-Apr-2015
• Refers: ASTM E177-14 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2014
• Refers: ASTM D523-14 - Standard Test Method for Specular Gloss
• Effective Date: 01-Jan-2014
• Refers: ASTM E284-13b - Standard Terminology of Appearance
• Effective Date: 01-Nov-2013
• Refers: ASTM E284-13a - Standard Terminology of Appearance
• Effective Date: 01-Jun-2013
• Refers: ASTM E177-13 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2013
• Refers: ASTM E691-13 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-May-2013
• Refers: ASTM E284-13 - Standard Terminology of Appearance
• Effective Date: 01-Jan-2013
• Refers: ASTM E284-12 - Standard Terminology of Appearance
• Effective Date: 01-Jul-2012
• Refers: ASTM E308-12 - Standard Practice for Computing the Colors of Objects by Using the CIE System
• Effective Date: 01-Jul-2012
• Refers: ASTM E179-12 - Standard Guide for Selection of Geometric Conditions for Measurement of Reflection and Transmission Properties of Materials
• Effective Date: 01-Jul-2012
• Refers: ASTM E1347-06(2011) - Standard Test Method for Color and Color-Difference Measurement by Tristimulus Colorimetry
• Effective Date: 01-Nov-2011

Overview

ASTM E430-23 is the globally recognized standard for the measurement of gloss on high-gloss surfaces using abridged goniophotometry. Developed by ASTM International, this standard provides two test methods for quantifying key reflection characteristics responsible for the visual appearance of gloss. Accurate gloss measurement is critical in the automotive, architectural, and manufacturing sectors, where consistency of appearance and surface quality greatly impact product perception and value.

These standardized test methods help ensure reliable, repeatable evaluation of high-gloss surfaces, particularly metallic finishes and high-gloss nonmetallic coatings, by establishing uniform procedures and terminology consistent with international best practices.

Key Topics

• Gloss Measurement
  The standard defines procedures for measuring the reflective properties associated with high-gloss appearance, distinguishing between true specular gloss, haze, and the distinctness-of-image (DOI).

• Test Methods A and B

  • Method A: Evaluates surfaces at a 20° specular angle, measuring gloss and narrow-angle reflection haze.
  • Method B: Uses a 30° specular angle and includes measurements for specular gloss, DOI, narrow- and wide-angle haze.

• Terminology and Definitions
  Clear, standardized definitions for terms such as reflectance, reflection haze, distinctness-of-image, and more, ensure consistency across industries.

• Apparatus and Standards
  Specifications for the abridged goniophotometer and requirements for gloss calibration standards (metallic and nonmetallic) underpin the reproducibility of measurements.

• Precision and Repeatability
  The standard outlines repeatability and reproducibility expectations, supporting interlaboratory comparison and product quality control.

Applications

ASTM E430-23 serves a critical role in industries where high-gloss finishes are both an aesthetic and a functional requirement. Typical applications include:

• Automotive Industry:
  Ensuring color and gloss uniformity on body panels, trim, and finishes to maintain product appeal and brand consistency.

• Architectural Metals and Surfaces:
  Verifying the appearance of finishing treatments on exterior and interior installations, upholding design intent and premium surface quality.

• Consumer Goods Manufacturing:
  Comparing high-gloss coatings on appliances, electronics, and decorative items to desired specifications, supporting marketing claims and consumer expectations.

• Quality Control and R&D:
  Providing reliable measurement protocol for laboratory and production environments to monitor gloss uniformity, troubleshoot finish defects, and validate process improvements.

Related Standards

To support comprehensive surface appearance evaluation, ASTM E430-23 references and complements several related standards, including:

• ASTM D523, Test Method for Specular Gloss
  Widely used for general gloss measurement on various surfaces.

• ASTM D2457, Test Method for Specular Gloss of Plastic Films and Solid Plastics
  Specialized for gloss assessment on plastics and films.

• ASTM E308, Practice for Computing the Colors of Objects by Using the CIE System
  Guides color evaluation of materials, providing a distinction from gloss measurement.

• ASTM E171, Practice for Conditioning and Testing Flexible Barrier Packaging
  Supports standardized conditioning and testing environments.

• ASTM E1347, Test Method for Color and Color-Difference Measurement by Tristimulus Colorimetry
  Focuses on color measurement, a complementary appearance attribute.

Adopting ASTM E430-23 aids manufacturers, laboratories, and specifiers in delivering visually consistent high-gloss products, enhancing quality assurance and global market acceptance. For authoritative reference, always consult the most recent version of the official ASTM standard.

Standards Content (Sample)

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: E430 − 23
Standard Test Methods for
Measurement of Gloss of High-Gloss Surfaces by Abridged
Goniophotometry
This standard is issued under the fixed designation E430; 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 D2457 Test Method for Specular Gloss of Plastic Films and
Solid Plastics
1.1 These test methods cover the measurement of the
E171 Practice for Conditioning and Testing Flexible Barrier
reflection characteristics responsible for the glossy appearance
Packaging
of high-gloss surfaces. Two test methods, A and B, are
E177 Practice for Use of the Terms Precision and Bias in
provided for evaluating such surface characteristics at specular
ASTM Test Methods
angles of 20° and 30°, respectively. These test methods are not
E179 Guide for Selection of Geometric Conditions for
suitable for diffuse finish surfaces nor do they measure color,
Measurement of Reflection and Transmission Properties
another appearance attribute.
of Materials
1.2 As originally developed by Tingle and others (see Refs
E284 Terminology of Appearance
1 and 2), the test methods were applied only to bright metals.
E308 Practice for Computing the Colors of Objects by Using
Recently they have been applied to high-gloss automotive
the CIE System
finishes and other nonmetallic surfaces.
E430 Test Methods for Measurement of Gloss of High-Gloss
Surfaces by Abridged Goniophotometry
1.3 The DOI of a glossy surface is generally independent of
its curvature. The DOI measurement by this test method is E691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
limited to flat or flattenable surfaces.
E1347 Test Method for Color and Color-Difference Mea-
1.4 This standard does not purport to address all of the
surement by Tristimulus Colorimetry
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3. Terminology
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
3.1 Definitions:
1.5 This international standard was developed in accor-
3.1.1 Appearance terms in this test method are in accor-
dance with internationally recognized principles on standard-
dance with Terminology E284.
ization established in the Decision on Principles for the
3.1.2 Terms that are defined in Terminology E284, but have
Development of International Standards, Guides and Recom-
a specific definition in this method are
mendations issued by the World Trade Organization Technical
3.1.3 reflectance, p, n—ratio of the reflected radiant or
Barriers to Trade (TBT) Committee.
luminous flux to the incident flux in the given conditions.
(Terminology E284)
2. Referenced Documents
3.1.3.1 Discussion—The term reflectance is often used in a
2.1 ASTM Standards: general sense or as an abbreviation for reflectance factor. Such
D523 Test Method for Specular Gloss usage is not assumed in this method. The definition may
require that the term be modified by adjectives denoting the
spectral and geometric conditions of measurement.
These test methods are under the jurisdiction of ASTM Committee E12 on
3.2 Definitions of Terms Specific to This Standard:
Color and Appearance and are the direct responsibility of Subcommittee E12.03 on
Geometry. 3.2.1 reflection haze, H, n—for a specified specular angle,
Current edition approved June 1, 2023. Published August 2023. Originally
ratio of flux reflected at a specified angle (or angles) from the
approved in 1971. Last previous edition approved in 2019 as E430 – 19. DOI:
specular direction to the flux similarly reflected at the specular
10.1520/E0430-23.
angle by a specified gloss standard.
The boldface numbers in parentheses refer to the list of references at the end of
this method.
3.2.1.1 Discussion—Modifiers may be used to specify the
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
angles at which the haze is measured (for example, 2°, –5° or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
15°); whether –H or a logarithmic form is to be stated; or
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. whether H is to be compensated for the luminance of the
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E430 − 23
specimen by multiplication by Y /Y , where n denotes the
specimen n
reference white; or any combination of these.
3.2.2 metallic brightness, n—freedom of a metal surface
from diffuse haze or texture.
3.2.3 ‘with-machine’ direction, n—the axis of a specimen
that is parallel to the direction of mill rolling or extrusion, or
other surface-finish texture.
3.2.4 ‘across-machine’ direction, n—the perpendicular to
‘with-machine’ direction.
4. Summary of Test Method
4.1 Several geometrically different measures of light re-
flected by a surface are proposed for use in describing its gloss.
4.1.1 Test Method A—A specular gloss is measured at 20° in
accordance with Test Method D523, and narrow-angle reflec-
tion haze is measured at 18.1° and 21.9°. For additional
information on the selection of geometric conditions, see
Guide E179.
4.1.2 Test Method B—A gloss reflectance factor is measured
at 30° to the specimen normal using narrow illuminator and
receiver aperture angles (0.5° wide maximum). Distinctness-
of-image gloss is measured at 29.7° and 30.3°. Narrow-angle
(2°) reflection haze is measured at 28° and 32°, and wide-angle
(15°) reflection haze at 15°.
5. Significance and Use
5.1 The gloss of metallic finishes is important commercially
on metals for automotive, architectural, and other uses where
these metals undergo special finishing processes to produce the
appearances desired. It is important for the end-products,
which use such finished metals that parts placed together have
the same glossy appearance.
FIG. 1 Optical Diagram of the Apparatus for Method A
5.2 It is also important that automotive finishes and other
high-gloss nonmetallic surfaces possess the desired finished
appearance. The present method identifies by measurements
important aspects of finishes. Those having identical sets of
reflection haze measurement. The angular dimensions of the
numbers normally have the same gloss characteristics. It
specularly reflected image of the source slit in the plane of
usually requires more than one measurement to identify
measurement and the angular dimensions of the receiver
properly the glossy appearance of any finish (see Refs 3 and 4).
windows in this plane of measurement shall be as shown in
Table 1.
6. Apparatus
6.1.2 Geometric Conditions for Test Method B—The direc-
6.1 The apparatus shall be an abridged goniophotometer
tion of incidence shall be 30°. The directions of view shall be
(see Fig. 1 and Fig. 2). The abridged goniophotometer may
opposite the direction of incidence at 30° for specular
have a fixed angle of incidence (for Test Method A, 20° and for
reflectance, 29.7° and 30.3° for distinctness of image
Test Method B, 30°) and specific fixed directions of view at
comparisons, 28° and 32° for narrow-angle haze comparisons,
which the flux from the specimen is measured (see Table 1 and
and 15° for wide-angle haze comparisons. The angular dimen-
Table 2).
sions of the mirror reflected image of the source slit in the
6.1.1 Geometric Conditions for Test Method A—The direc-
plane of measurement and the angular dimensions of the
tion of incidence shall be 20° 6 0.1°. The directions of view
receiver windows in this plane of measurement shall be as
shall be opposite the direction of incidence, at 20° for specular
shown in Table 2.
gloss measurement and at 18.1° and 21.9° for narrow-angle
6.1.3 Spectral Conditions—The measurement shall be made
with visible light to give results in accordance with the CIE
spectral luminous efficiency function V(λ), which is identical
The sole source of supply of the apparatus known to the committee at this time
for Method A is BYK-Gardner USA, Columbia, MD, and for Method B is TRICOR
with y¯ in the CIE 1931 standard observer and CIE standard
Systems Inc., Elgin, IL. If you are aware of alternative suppliers, please provide this
illuminant C (see Practice E308 and Test Method E1347). If
information to ASTM International Headquarters. Your comments will receive
another illuminant such as A, is used, this shall be specified in
careful consideration at a meeting of the responsible technical committee, which
you may attend. the report.
E430 − 23
FIG. 2 Optical Diagram of the Apparatus for Method B
TABLE 1 Dimensions of the Specular Image of the Source-Slit and of the Receptor Windows Measured in the Plane of the Receiving
Windows (see Fig. 1)
Source-Slit Specular Gloss Haze Receiver
Method A
Specular Image, ° Receiver Window, ° Window, °
Angle of center of window (measured from 20.0 ± 0.1 20.0 ± 0.1 18.1 ± 0.1
perpendicular to specimen surface) and
21.9 ± 0.1
Width (in the plane of the angle of reflection) 0.75 ± 0.1 1.8 ± 0.05 1.8 ± 0.1
Length (across the plane of the angle of reflection) 2.5 ± 0.25 3.6 ± 0.1 5.5 ± 0.25
6.1.4 Polarization—The incident flux shall be unpolarized 7. Standards
and the receiver shall be insensitive to the state of polarization
7.1 Three calibrated standards of good planarity shall be
of the reflected luminous flux.
available in either a set of metals or a set of nonmetals,
6.1.5 Clamp—For Test Method B, a rotatable clamp of the depending upon which type of surface is measured.
type shown in Fig. 3 may be used for flattening and positioning
7.2 High-Gloss Standards:
the specimen during measurement.
7.2.1 High-Gloss Standard for Metals shall be of aluminum,
6.1.6 Weights—For Test Method B, a unit orientation or a evaporated onto glass and covered with a protective coating of
weight similar to the type shown in Fig. 4 may be used for
silicon monoxide, and calibrated for specular gloss and
flattening and positioning the specimen during measurement. distinctness-of-image gloss.
E430 − 23
TABLE 2 Dimensions of the Mirror Image of the Source-Slit and of the Receptor Windows Measured in the Plane of the Receiving
Windows (see Fig. 2)
Source-Slit Mirror Specular Receiver Distinctness-of-Image (±0.29) Haze Receiver
Method B
Image, ° Window, ° Receiver Window, ° Windows,°
Angle of center of window (measured from 30 30 30.3 and 29.7 28 and 32 (2° Haze)
perpendicular to specimen surface) 15 (15° Haze)
Width (in the plane of the angle of reflection) 0.44 ± 0.01 0.4 ± 0.01 0.14 ± 0.01 0.4 ± 0.1 (2° Haze)
1.91 ± 0.1 (15° Haze)
Length (across the plane of the angle of 5.0 ± 1 0.62 ± .01 0.62 ± .01 0.62 ± .01 (2° Haze)
reflection) 0.62 ± .01 (15° Haze)
FIG. 3 A Rotatable Clamp Suggested for Flattening the Specimen and Positioning It During Measurement
FIG. 4 Suggested Methods for Maintaining or Flattening Specimen During Measurement (Method B)
section). Repeat the calculation for n = 1.527 and the same specular
7.2.2 High-Gloss Standard for Nonmetals shall be of highly
p
angle; the result for 30° is 4.5069 % and for 20°, 4.3769 %. The new scale
polished black glass with a refractive index of approximately
value for 30° is 100 × (4.5069 ⁄5.0436) = 89.4, and for 20°,
n = 1.527, calibrated for specular gloss and reflection haze,
D
100 × (4.3769 ⁄4.9078) = 89.2. (The latter value is also given in Test
and assigned a scale value of G = 89.4 for a specular angle of
s Method D523.)
30° (Test Methods B) or G = 89.2 for a specular angle of 20°
s
7.3 Intermediate Standards:
(Test Method A).
7.3.1 Intermediate Standard for Metals shall be of either
NOTE 1—To determine the scale value, calculate the first-surface
chromium evaporated onto glass and covered with a protective
(Fresnel) reflectance (see Test Method D2457, Instrumental Components
coating of silicon monoxide, or of bright sheet aluminum with
in Apparatus section) for n = 1.567 and the specular angle of interest; for
D
protective coating and calibrated for specular gloss and
30° it is 5.0436 % and for 20° it is 4.9078 %. Assign this a scale value of
100 (see Test Method D523, Primary Standards in Reference Standards distinctness-of-image gloss.
E430 − 23
7.3.2 Intermediate Standard for Nonmetals shall be of a 10.4 Record the following quantities:
ceramic material, such as porcelain enamel on steel, and 10.4.1 For Test Method A, readings of (a) the 20° specular
calibrated for specular gloss and distinctness-of-image gloss. gloss, R ; (b) the reflection haze, H; and (c) the luminous
s,20
reflectance, Y.
7.4 Diffuse Standards shall have a reflectance factor sub-
10.4.2 For Test Method B, readings of (a) gloss reflectance
stantially constant over the angular range of the instrument.
factor (specular gloss), R at 30°; (b) distinctness-of-image
s,30
7.5 Care of Standards—It is essential that the standards be
gloss; (c) 2° reflection haze; H ; and (d) 15° reflection haze,
kept clean and free of scratches as well as from contact with
H . The quantities in (b), (c), and (d) may be either gloss
contaminating materials. The cleaning method specified by the
reflectance factors or values of H, which are their ratios to the
instrument manufacturer shall be followed and the standards
specular gloss reflectance factor recorded in (a).
should be checked at regular intervals against reference stan-
10.5 Measure at least three areas of each specimen.
dards held in reserve.
10.6 From these same areas, read 2° haze for the “across-
8. Specimens machine direction,” being careful to flatten the test surface and
orient the specular beam in each case.
8.1 Specimens shall be obtained from test samples by
selecting areas that are plane and representative of each sample 10.7 Take readings on the standards at the end of the series
of observations to ensure that the instrument has remained in
being tested. Every specimen must be at least 2 ⁄4 in. (70 mm)
in the smallest dimension. Specimens may be larger so long as calibration throughout the operation.
NOTE 3—Poor measurement repeatability may be due to failures to
it is possible to insert them into the instrument and flatten them
sufficiently flatten the specimen.
properly for measurement.
8.2 For Method B, a specimen may be considered to be
11. Calculation
properly flattened when no portion of the measured specimen
11.1 For Test Method A, calculate the mean of three
surface deviates from the sample plane by more than 0.15 deg.
readings of each specimen for:
11.1.1 Specular gloss, R at 20°.
s,20
9. Preparation and Standardization of Apparatus
11.1.2 One or more of the following, as required:
9.1 The instrument must be used in a clean dry area free of
11.1.2.1 Reflection haze, H .
drafts. Standard laboratory conditions are recommended (see
11.1.2.2 Logarithmic reflection haze, H = 1285
20,log
Referenced Documents section in Specification E171). Voltage
log[(H /20) + 1].
regulation to 60.01 % must be incorporated in the instrument,
11.1.2.3 Compensated reflection haze, H = H -
20,comp 20, speci
or supplied separately. Follow manufacturer’s recommenda-
men − (H × Y /Y ).
20,n specimen n
tions for instrument warm-up.
NOTE 4—H may also be calculated as a compensated quantity by
20,log
9.2 Standardization—Adjust the instrument to read the same
using H in place of H in 11.1.2.2. Compensated quantities shall
20, comp 20
be used when comparing specimens with different values of Y.
gloss reflectance factor for the intensity of light reflected from
the diffuse standard through the specular, distinctness-of-
11.2 For Test Method B, calculate the mean of three
image, and haze apertures. Adjust the instrument to read values
readings for each specimen for:
of specular gloss and distinctness-of-image gloss assigned the
11.2.1 Specular gloss, R , at 30°.
s,30
aluminum mirror if metal surfaces are being measured; or the
11.2.2 Distinctness-of-image gloss, 100 × (1 – H ), evalu-
0.3
black gloss standard if nonmetal surfaces are b
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E430 − 19 E430 − 23
Standard Test Methods for
Measurement of Gloss of High-Gloss Surfaces by Abridged
Goniophotometry
This standard is issued under the fixed designation E430; 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
1.1 These test methods cover the measurement of the reflection characteristics responsible for the glossy appearance of high-gloss
surfaces. Two test methods, A and B, are provided for evaluating such surface characteristics at specular angles of 20° and 30°,
respectively. These test methods are not suitable for diffuse finish surfaces nor do they measure color, another appearance attribute.
1.2 As originally developed by Tingle and others (see Refs 1 and 2), the test methods were applied only to bright metals. Recently
they have been applied to high-gloss automotive finishes and other nonmetallic surfaces.
1.3 The DOI of a glossy surface is generally independent of its curvature. The DOI measurement by this test method is limited
to flat or flattenable surfaces.
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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.5 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.
2. Referenced Documents
2.1 ASTM Standards:
D523 Test Method for Specular Gloss
D2457 Test Method for Specular Gloss of Plastic Films and Solid Plastics
E171 Practice for Conditioning and Testing Flexible Barrier Packaging
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E179 Guide for Selection of Geometric Conditions for Measurement of Reflection and Transmission Properties of Materials
E284 Terminology of Appearance
E308 Practice for Computing the Colors of Objects by Using the CIE System
E430
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E1347 Test Method for Color and Color-Difference Measurement by Tristimulus Colorimetry
These test methods are under the jurisdiction of ASTM Committee E12 on Color and Appearance and are the direct responsibility of Subcommittee E12.03 on Geometry.
Current edition approved Nov. 1, 2019June 1, 2023. Published December 2019August 2023. Originally approved in 1971. Last previous edition approved in 20112019
as E430 – 11.E430 – 19. DOI: 10.1520/E0430-19.10.1520/E0430-23.
The boldface numbers in parentheses refer to the list of references at the end of this method.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E430 − 23
3. Terminology
3.1 Definitions:
3.1.1 Appearance terms in this test method are in accordance with Terminology E284.
3.1.2 Terms that are defined in Terminology E284, but have a specific definition in this method are
3.1.3 reflectance, p, n—ratio of the reflected radiant or luminous flux to the incident flux in the given conditions. (Terminology
E284)
3.1.3.1 Discussion—
The term reflectance is often used in a general sense or as an abbreviation for reflectance factor. Such usage is not assumed in this
method. The definition may require that the term be modified by adjectives denoting the spectral and geometric conditions of
measurement.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 reflection haze, H, n—for a specified specular angle, ratio of flux reflected at a specified angle (or angles) from the specular
direction to the flux similarly reflected at the specular angle by a specified gloss standard.
3.2.1.1 Discussion—
Modifiers may be used to specify the angles at which the haze is measured (for example, 2°, –5° or 15°); whether –H or a
logarithmic form is to be stated; or whether H is to be compensated for the luminance of the specimen by multiplication by
Y /Y , where n denotes the reference white; or any combination of these.
specimen n
3.2.2 metallic brightness, n—freedom of a metal surface from diffuse haze or texture.
3.2.3 ‘with-machine’ direction, n—the axis of a specimen that is parallel to the direction of mill rolling or extrusion, or other
surface-finish texture.
3.2.4 ‘across-machine’ direction, n—the perpendicular to ‘with-machine’ direction.
4. Summary of Test Method
4.1 Several geometrically different measures of light reflected by a surface are proposed for use in describing its gloss.
4.1.1 Test Method A—A specular gloss is measured at 20° in accordance with Test Method D523, and narrow-angle reflection haze
is measured at 18.1° and 21.9°. For additional information on the selection of geometric conditions, see Guide E179.
4.1.2 Test Method B—A gloss reflectance factor is measured at 30° to the specimen normal using narrow illuminator and receiver
aperture angles (0.5° wide maximum). Distinctness-of-image gloss is measured at 29.7° and 30.3°. Narrow-angle (2°) reflection
haze is measured at 28° and 32°, and wide-angle (15°) reflection haze at 15°.
5. Significance and Use
5.1 The gloss of metallic finishes is important commercially on metals for automotive, architectural, and other uses where these
metals undergo special finishing processes to produce the appearances desired. It is important for the end-products, which use such
finished metals that parts placed together have the same glossy appearance.
5.2 It is also important that automotive finishes and other high-gloss nonmetallic surfaces possess the desired finished appearance.
The present method identifies by measurements important aspects of finishes. Those having identical sets of numbers normally
have the same gloss characteristics. It usually requires more than one measurement to identify properly the glossy appearance of
any finish (see Refs 3 and 4).
6. Apparatus
6.1 The apparatus shall be an abridged goniophotometer (see Fig. 1 and Fig. 2). The abridged goniophotometer may have a fixed
E430 − 23
FIG. 1 Optical Diagram of the Apparatus for Method A
angle of incidence (for Test Method A, 20° and for Test Method B, 30°) and specific fixed directions of view at which the flux
from the specimen is measured (see Table 1 and Table 2).
6.1.1 Geometric Conditions for Test Method A—The direction of incidence shall be 20° 6 0.1°. The directions of view shall be
opposite the direction of incidence, at 20° for specular gloss measurement and at 18.1° and 21.9° for narrow-angle reflection haze
measurement. The angular dimensions of the specularly reflected image of the source slit in the plane of measurement and the
angular dimensions of the receiver windows in this plane of measurement shall be as shown in Table 1.
6.1.2 Geometric Conditions for Test Method B—The direction of incidence shall be 30°. The directions of view shall be opposite
the direction of incidence at 30° for specular reflectance, 29.7° and 30.3° for distinctness of image comparisons, 28° and 32° for
narrow-angle haze comparisons, and 15° for wide-angle haze comparisons. The angular dimensions of the mirror reflected image
of the source slit in the plane of measurement and the angular dimensions of the receiver windows in this plane of measurement
shall be as shown in Table 2.
6.1.3 Spectral Conditions—The measurement shall be made with visible light to give results in accordance with the CIE spectral
luminous efficiency function V(λ), which is identical with y¯ in the CIE 1931 standard observer and CIE standard illuminant C (see
Practice E308 and Test Method E1347). If another illuminant such as A, is used, this shall be specified in the report.
The sole source of supply of the apparatus known to the committee at this time for Method A is BYK-Gardner USA, Columbia, MD, and for Method B is TRICOR
Systems Inc., Elgin, IL. If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful
consideration at a meeting of the responsible technical committee, which you may attend.
E430 − 23
FIG. 2 Optical Diagram of the Apparatus for Method B
TABLE 1 Dimensions of the Specular Image of the Source-Slit and of the Receptor Windows Measured in the Plane of the Receiving
Windows (see Fig. 1)
Source-Slit Specular Gloss Haze Receiver
Method A
Specular Image, ° Receiver Window, ° Window, °
Angle of center of window (measured from 20.0 ± 0.1 20.0 ± 0.1 18.1 ± 0.1
perpendicular to specimen surface) and
21.9 ± 0.1
Width (in the plane of the angle of reflection) 0.75 ± 0.1 1.8 ± 0.05 1.8 ± 0.1
Length (across the plane of the angle of reflection) 2.5 ± 0.25 3.6 ± 0.1 5.5 ± 0.25
6.1.4 Polarization—The incident flux shall be unpolarized and the receiver shall be insensitive to the state of polarization of the
reflected luminous flux.
6.1.5 Clamp—For Test Method B, a rotatable clamp of the type shown in Fig. 3 may be used for flattening and positioning the
specimen during measurement.
6.1.6 Weights—For Test Method B, a unit orientation or a weight similar to the type shown in Fig. 4 may be used for flattening
and positioning the specimen during measurement.
E430 − 23
TABLE 2 Dimensions of the Mirror Image of the Source-Slit and of the Receptor Windows Measured in the Plane of the Receiving
Windows (see Fig. 2)
Source-Slit Mirror Specular Receiver Distinctness-of-Image (±0.29) Haze Receiver
Method B
Image, ° Window, ° Receiver Window, ° Windows,°
Angle of center of window (measured from 30 30 30.3 and 29.7 28 and 32 (2° Haze)
perpendicular to specimen surface) 15 (15° Haze)
Width (in the plane of the angle of reflection) 0.44 ± 0.01 0.4 ± 0.01 0.14 ± 0.01 0.4 ± 0.1 (2° Haze)
1.91 ± 0.1 (15° Haze)
Length (across the plane of the angle of 5.0 ± 1 0.62 ± .01 0.62 ± .01 0.62 ± .01 (2° Haze)
reflection) 0.62 ± .01 (15° Haze)
FIG. 3 A Rotatable Clamp Suggested for Flattening the Specimen and Positioning It During Measurement
FIG. 4 Suggested Methods for Maintaining or Flattening Specimen During Measurement (Method B)
7. Standards
7.1 Three calibrated standards of good planarity shall be available in either a set of metals or a set of nonmetals, depending upon
which type of surface is measured.
7.2 High-Gloss Standards:
7.2.1 High-Gloss Standard for Metals shall be of aluminum, evaporated onto glass and covered with a protective coating of silicon
monoxide, and calibrated for specular gloss and distinctness-of-image gloss.
E430 − 23
7.2.2 High-Gloss Standard for Nonmetals shall be of highly polished black glass with a refractive index of approximately
n = 1.527, calibrated for specular gloss and reflection haze, and assigned a scale value of G = 89.4 for a specular angle of 30°
D s
(Test Methods A and C) B) or G = 89.2 for a specular angle of 20° (Test Method B).A).
s
NOTE 1—To determine the scale value, calculate the first-surface (Fresnel) reflectance (see Test Method D2457, Instrumental Components in Apparatus
section) for n = 1.567 and the specular angle of interest; for 30° it is 5.0436 % and for 20° it is 4.9078 %. Assign this a scale value of 100 (see Test
D
Method D523, Primary Standards in Reference Standards section). Repeat the calculation for n = 1.527 and the same specular angle; the result for 30°
p
is 4.5069 % and for 20°, 4.3769 %. The new scale value for 30° is 100 × (4.5069 ⁄5.0436) = 89.4, and for 20°, 100 × (4.3769 ⁄4.9078) = 89.2. (The latter
value is also given in Test Method D523.)
7.3 Intermediate Standards:
7.3.1 Intermediate Standard for Metals shall be of either chromium evaporated onto glass and covered with a protective coating
of silicon monoxide, or of bright sheet aluminum with protective coating and calibrated for specular gloss and distinctness-of-
image gloss.
7.3.2 Intermediate Standard for Nonmetals shall be of a ceramic material, such as porcelain enamel on steel, and calibrated for
specular gloss and distinctness-of-image gloss.
7.4 Diffuse Standards shall have a reflectance factor substantially constant over the angular range of the instrument.
7.5 Care of Standards—It is essential that the standards be kept clean and free of scratches as well as from contact with
contaminating materials. The cleaning method specified by the instrument manufacturer shall be followed and the standards should
be checked at regular intervals against reference standards held in reserve.
8. Specimens
8.1 Specimens shall be obtained from test samples by selecting areas that are plane and representative of each sample being tested.
Every specimen must be at least 2 ⁄4 in. (70 mm) in the smallest dimension. Specimens may be larger so long as it is possible to
insert them into the instrument and flatten them properly for measurement.
8.2 For Method A,B, a specimen may be considered to be properly flattened when no portion of the measured specimen surface
deviates from the sample plane by more than 0.15 deg.
9. Preparation and Standardization of Apparatus
9.1 The instrument must be used in a clean dry area free of drafts. Standard laboratory conditions are recommended (see
Referenced Documents section in Specification E171). Voltage regulation to 60.01 % must be incorporated in the instrument, or
supplied separately. Follow manufacturer’s recommendations for instrument warm-up.
9.2 Standardization—Adjust the instrument to read the same gloss reflectance factor for the intensity of light reflected from the
diffuse standard through the specular, distinctness-of-image, and haze apertures. Adjust the instrument to read values of specular
gloss and distinctness-of-image gloss assigned the aluminum mirror if metal surfaces are being measured; or the black gloss
standard if nonmetal surfaces are being measured. If the instrument does not then read the appropriate intermediate standard within
the limits set by the instrument manufacturer, refocus or restandardize following the manufacturer’s instructions.
10. Procedure
10.1 Bring the specimen to the instrument for measurement. Be sure the specimen is flat.
NOTE 2—The measured DOI will be erroneously low in the measurement direction if there is excessive specimen curvature in that direction.
10.2 For Test Method B, be certain that the specular sensor is centered on the specimen-reflected specular light beam. The full
goniophotometer, shown in Fig. 5, identifies the specular direction by the peak of the goniophotometric curve.
E430 − 23
FIG. 5 Recording Goniophotometer Showing Viewing Angle, v, Incidence Angle, i, and Their Respective Field Angles, 2K and 2K
v i
10.3 Rotate the specimen in its own plane to find the orientation, giving the maximum specular signal. This specimen orientation
is called the “machine direction” because it generally coincides with the direction of travel of a sheet or film material through a
processing machine.
10.4 Record the following quantities:
10.4.1 For Test Method A, readings of (a) the 20° specular gloss, R ; (b) the reflection haze, H; and (c) the luminous reflectance,
s,20
Y.
10.4.2 For Test Method B, readings of (a) gloss reflectance factor (specular gloss), R at 30°; (b) distinctness-of-image gloss;
s,30
(c) 2° reflection haze; H ; and (d) 15° reflection haze, H . The quantities in (b),(c), and (d) may be either gloss reflectance factors
2 15
or values of H, which are their ratios to the specular gloss reflectance factor recorded in (a).
10.5 Measure at least three areas of each specimen.
10.6 From these same areas, read 2° haze for the “across-machine direction,” being careful to flatten the test surface and orient
the specular beam in each case.
10.7 Take readings on the standards at the end of the series of observations to ensure that the instrument has remained in
calibration throughout the operation.
...