ASTM C346-87(2004)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
SIGNIFICANCE AND USE
This test method may be used to compare the gloss of porcelain enamel, ceramic, and other finishes or to provide a comparison of their resistance to attack from acid, alkali, or other environmental factors by measurement of gloss loss.
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 Test Method D 523 for 20, 60, and 85-deg geometries. Values generally cannot be predicated for one geometry from measurements made with another.
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.
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e1
Designation:C346–87(Reapproved2004)
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—Keywords were added editorially in September 2004.
1. Scope 3.1.1 specular gloss—ratio of reflected to incident light,
times 1000, for specified apertures of illumination and recep-
1.1 This test method covers the determination of the specu-
tionwhentheaxisofreceptioncoincideswiththemirrorimage
lar gloss of porcelain enameled specimens, but may be appli-
of the axis of illumination.
cable to other specimens having similar reflection characteris-
tics. This test method may be used to compare the gloss of
NOTE 3—In this operational definition, the quantity defined as specular
porcelainenameledspecimensortoprovideanindexofacidor
gloss is composed of surface-reflected and body-reflected components.
For some low-gloss measurements, an approximate evaluation of the
abrasion resistance by measurement of gloss loss.
surface-reflected component of specular gloss may be required (see
NOTE 1—Specular gloss is one of several related appearance attributes
Section 9).
that produce the sensation of glossiness. For this reason, specular gloss
3.1.2 45-deg specular gloss—fraction of visible light inci-
measurements may not always correlate well with visual rankings of
dent upon the specimens at 45° to the normal that is reflected
glossiness.
NOTE 2—Improved correlations with visual judgments can sometimes
in the direction of mirror reflection.
be achieved by the use of instruments with different geometries than those
NOTE 4—Under ideal conditions, the incident beam should consist of
specified herein. Refer to Test Method D 523 for 20, 60, and 85-deg
parallel light, and only light reflected in the true direction of mirror
geometries. Values generally cannot be predicated for one geometry from
reflection should be accepted for measurement.
measurements made with another.
3.1.3 source aperture—angular size (solid angle) of the
1.2 This standard does not purport to address all of the
light source (lamp filament, if an incandescent source is used)
safety concerns, if any, associated with its use. It is the
measured from the center of the incident beam lens.
responsibility of the user of this standard to establish appro-
3.1.4 receptor aperture—angular size (solid angle) of the
priate safety and health practices and determine the applica-
receptor window, measured from the center of the receptor
bility of regulatory limitations prior to use.
lens.
2. Referenced Documents
4. Significance and Use
2.1 ASTM Standards:
4.1 This test method may be used to compare the gloss of
D 523 Test Method for Specular Gloss
porcelain enamel, ceramic, and other finishes or to provide a
E 97 Method of Test for Directional Reflectance Factor,
comparison of their resistance to attack from acid, alkali, or
45-Deg 0-Deg, of Opaque Specimens by Broad-Band
other environmental factors by measurement of gloss loss.
Filter Reflectometry
5. Apparatus
3. Terminology
5.1 Instrumental Components—The apparatus shall consist
3.1 Definitions:
of an incandescent light source and lens furnishing an incident
beam of rays of required aperture, means for locating the
ThistestmethodisunderthejurisdictionofASTMCommitteeB08onMetallic
surface of the specimen, and a receptor located to receive the
and Inorganic Coatings and is the direct responsibility of Subcommittee B08.12 on
required pyramid of rays reflected from the specimen. The
Materials for Porcelain Enamel and Ceramic-Metal Systems, and is based on the
“GlossTestforPorcelainEnamels,” Bulletin T-18,ofthePorcelainEnamelInstitute,
receptor shall be a photosensitive device having maximum
1111 N. 19th St., Suite 200, Arlington, VA 22209.
response near the middle of the visible region of the spectrum.
Current edition approved Aug. 1, 2004. Published September 2004. Originally
e1 5.2 Geometric Conditions—The axis of the incident beam
approved in 1954. Last previous edition approved in 1998 as C 346 – 87 (1998) .
For referenced ASTM standards, visit the ASTM website, www.astm.org, or shall be 45° from the perpendicular to the specimen surface.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
The axis of the receptor beam shall be coincident with the
Standards volume information, refer to the standard’s Document Summary page on
mirror image of the axis of the incident beam. A flat piece of
the ASTM website.
polished black glass in the specimen position shall form an
Withdrawn.
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C346–87 (2004)
image of the source in the center of the receptor window. The the instrument readings for the latter standards do not agree
angular dimensions of the source and receptor shall be as with the assigned values to within two gloss units, the
specified below: instrument optics may require readjustment; preferably, this
should be done by the manufacturer.
In Plane of Perpendicular to Plane
A A
Apertures Measurement, deg of Measurement, deg
8.3 Measure the gloss of at least three portions of each
Source 1.4 6 0.4 3.0 6 1.0
specimen surface. This will give an indication of gloss unifor-
Receiver 8.0 6 0.1 10.0 6 0.2
mity.
A 8.4 For evaluation of change of gloss of a single specimen,
“Plane of measurement” is the plane containing axes of illuminating and
viewing beams.
which may be used as a measurement of surface deterioration
of porcelain enameled or ceramic specimens, exercise particu-
6. Specular Gloss Standards
lar care to see that the glossmeter is in exactly the same
6.1 Specular Gloss Standards—Primary working standards position on the specimen for measurements before and after
shall be highly p
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