ASTM C346-87(1998)e1
(Test Method)Standard Test Method for 45-deg Specular Gloss of Ceramic Materials
Standard Test Method for 45-deg Specular Gloss of Ceramic Materials
SCOPE
1.1 This test method covers the determination of the specular gloss of porcelain enameled specimens, but may be applicable to other specimens having similar reflection characteristics. This test method may be used to compare the gloss of porcelain enameled specimens or to provide an index of acid or abrasion resistance by measurement of gloss loss. Note 1-Specular gloss is one of several related appearance attributes that produce the sensation of glossiness. For this reason, specular gloss measurements may not always correlate well with visual rankings of glossiness. Note 2-Improved correlations with visual judgments can sometimes be achieved by the use of instruments with different geometries than those specified herein. Refer to Method D523 for 20, 60, and 85-deg geometries. Values generally cannot be predicated for one geometry from measurements made with another.
1.2 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems 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
Relations
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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
e1
Designation: C 346 – 87 (Reapproved 1998)
Standard Test Method for
45-deg Specular Gloss of Ceramic Materials
This standard is issued under the fixed designation C 346; 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—Section 2 was editorially changed in November 1998.
NOTE 3—In this operational definition, the quantity defined as specular
1. Scope
gloss is composed of surface-reflected and body-reflected components.
1.1 This test method covers the determination of the specu-
For some low-gloss measurements, an approximate evaluation of the
lar gloss of porcelain enameled specimens, but may be appli-
surface-reflected component of specular gloss may be required (see
cable to other specimens having similar reflection characteris-
Section 9).
tics. This test method may be used to compare the gloss of
3.1.2 45-deg specular gloss—the fraction of visible light
porcelain enameled specimens or to provide an index of acid or
incident upon the specimens at 45° to the normal that is
abrasion resistance by measurement of gloss loss.
reflected in the direction of mirror reflection.
NOTE 1—Specular gloss is one of several related appearance attributes
NOTE 4—Under ideal conditions, the incident beam should consist of
that produce the sensation of glossiness. For this reason, specular gloss
parallel light, and only light reflected in the true direction of mirror
measurements may not always correlate well with visual rankings of
reflection should be accepted for measurement.
glossiness.
NOTE 2—Improved correlations with visual judgments can sometimes 3.1.3 source aperture—the angular size (solid angle) of the
be achieved by the use of instruments with different geometries than those
light source (lamp filament, if an incandescent source is used)
specified herein. Refer to Test Method D 523 for 20, 60, and 85-deg
measured from the center of the incident beam lens.
geometries. Values generally cannot be predicated for one geometry from
3.1.4 receptor aperture—the angular size (solid angle) of
measurements made with another.
the receptor window, measured from the center of the receptor
1.2 This standard does not purport to address all of the
lens.
safety concerns, if any, associated with its use. It is the
4. Significance and Use
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
4.1 This test method may be used to compare the gloss of
bility of regulatory limitations prior to use.
porcelain enamel, ceramic, and other finishes or to provide a
comparison of their resistance to attack from acid, alkali, or
2. Referenced Documents
other environmental factors by measurement of gloss loss.
2.1 ASTM Standards:
5. Apparatus
D 523 Test Method for Specular Gloss
E 1347 Test Method for Color and Color-Difference Mea-
5.1 Instrumental Components—The apparatus shall consist
surement by Tristimulus (Filter) Colorimetry
of an incandescent light source and lens furnishing an incident
beam of rays of required aperture, means for locating the
3. Terminology
surface of the specimen, and a receptor located to receive the
3.1 Definitions:
required pyramid of rays reflected from the specimen. The
3.1.1 specular gloss—the ratio of reflected to incident light,
receptor shall be a photosensitive device having maximum
times 1000, for specified apertures of illumination and recep-
response near the middle of the visible region of the spectrum.
tion when the axis of reception coincides with the mirror image
5.2 Geometric Conditions—The axis of the incident beam
of the axis of illumination.
shall be 45° from the perpendicular to the specimen surface.
The axis of the receptor beam shall be coincident with the
mirror image of the axis of the incident beam. A flat piece of
This test method is under the jurisdiction of ASTM Committee B-8 on Metallic
and Inorganic Coatings and is the direct responsibility of Subcommittee B08.12 on
polished black glass in the specimen position shall form an
Materials for Porcelain Enamel and Ceramic-Metal Systems, and is based on the
“Gloss Test for Porcelain Enamels,” Bulletin T-18, of the Porcelain Enamel Institute,
1111 N. 19th St., Suite 200, Arlington, VA 22209.
Current edition approved Aug. 28, 1987. Published October 1987. Originally Suitable instruments are available from: Hunter Associates Laboratory, Inc.,
published as C 346 – 54 T. Last previous edition C 346 – 59 (1972). 11495 Sunset Hills Rd., Reston, VA 22090, and Pacific Scientific Co., Gardner/
Annual Book of ASTM Standards, Vol 06.01. Neotec, Instr. Div., 2431 Linden Lane, Silver Springs, MD 20910.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C 346
image of the source in the center of the receptor window. The 8. Procedure
angular dimensions of the source and receptor shall be as
8.1 Operate the glossmeter according to the instructions of
specified below:
the manufacturer.
In Plane of Perpendicular to Plane
8.2 Set the instrument to read the assigned gloss value of a
A A
Apertures Measurement, deg of Measurement, deg
highly polished working standard; then read the gloss of lower
Source 1.4 6 0.4 3.0 6 1.0
Receiver 8.0 6 0.1 10.0 6 0.2 glass standards having poorer image-forming characteristics. If
the instrument readings for the latter standards do not agree
with the assigned values to within two gloss units, the
A
“Plane of measurement” is the plane containing axes of illuminating and
instrument optics may require readjustment; preferably, this
viewing beams.
should be done by the manufacturer.
8.3 Measure the gloss of at least three portions of each
6. Specular Gloss Standards
4 specimen surface. This will give an indication of gloss unifor-
6.1 Specular Gloss Standards —Primary working standards
mity.
shall be highly polished, plane, black-glass surfaces, or sur-
8.4 For evaluation of change of gloss of a single specimen,
faces of liquids for which the gloss is calculated from the angle
which
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.