Standard Practice for Selection of Coating Specimens for Appearance Measurements

SCOPE
1.1 This practice provides a guide to selection of specimens for appearance measurement as well as a discussion of factors to be considered in their preparation for measurement. Standardized selection and presentation procedures will assist in achieving agreement between evaluations carried out in different laboratories as well as helping to achieve better correlations between visual evaluations and instrumental measurements.  
Note 1 - This standard is not a practice for preparation of test panels of coatings; See Practice D 823.
1.2 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
09-May-1998
Current Stage
Ref Project

Relations

Buy Standard

Standard
ASTM D3964-80(1998) - Standard Practice for Selection of Coating Specimens for Appearance Measurements
English language
2 pages
sale 15% off
Preview
sale 15% off
Preview

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D 3964 – 80 (Reapproved 1998)
Standard Practice for
Selection of Coating Specimens for Appearance
Measurements
This standard is issued under the fixed designation D 3964; 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.
INTRODUCTION
In making appearance measurements, it is important that the specimens selected be representative
of the material of interest. Once selected, the specimens must be carefully examined to determine if
they are suitable for measurement, and if not, they must be cleaned or otherwise prepared. Careful
attention to these factors is necessary if the measurements are to be valid.
1. Scope ments. For this reason instrumental readings are affected
importantly by the manner in which specimens are selected and
1.1 This practice provides a guide to selection of specimens
presented for measurement. Reproducible measurements are
for appearance measurement as well as a discussion of factors
facilitated by standardization and control of test conditions.
to be considered in their preparation for measurement. Stan-
dardized selection and presentation procedures will assist in
5. General Requirements
achieving agreement between evaluations carried out in differ-
5.1 Specimen Size—The minimum size is dictated by the
ent laboratories as well as helping to achieve better correlations
size of the specimen port of the instrument to be used for
between visual evaluations and instrumental measurements.
measurement. When an instrument provides a choice of speci-
NOTE 1—This standard is not a practice for preparation of test panels of
men port sizes, use the largest port that can be completely
coatings; see Practices D 823.
covered by the specimen. A large measured area helps to
1.2 Thi. This standard does not purport to address all of the
minimize the effect of any small area nonuniformity and is
safety concerns, if any, associated with its use. It is the
therefore more likely to provide results that agree with the
responsibility of the user of this standard to establish appro-
involuntary averaging that takes place when specimens are
priate safety and health practices and determine the applica-
observed visually. A large specimen also permits the operator
bility of regulatory limitations prior to use.
to make measurements on several areas of the specimen when
desired thereby providing further specimen averaging.
2. Referenced Documents
5.2 Opacity—An opaque specimen shall be selected when-
2.1 ASTM Standards:
ever possible for gloss and color evaluation. When the speci-
D 823 Practices for Producing Films of Uniform Thickness
men is translucent or transparent, the following points should
of Paint, Varnish, and Related Products on Test Panels
be considered:
E 284 Terminology Relating to Appearance of Materials
5.2.1 For Gloss Evaluation—The specimen shall be suffi-
ciently thick that a secondary reflection from the back or
3. Terminology
second surface of the specimen cannot enter the receptor optics
3.1 Definitions:
of the glossmeter. When thin transparent specimens must be
3.1.1 For definitions of terms used in this practice, refer to
measured, adopt one of the following procedures:
Terminology E 284.
5.2.1.1 Back the specimen with a light absorbing material of
the same refractive index as the specimen, and in optical
4. Significance and Use
contact with it.
4.1 Many of the specimens that are regularly submitted to
5.2.1.2 Use an agreed upon specimen thickness, including
measurement depart in some degree from the ideal require-
coating and substrate and place a black backing behind the
specimen.
5.2.2 For Color Evaluation—The choice of backing of even
This practice is under the jurisdiction of ASTM Committee D-1 on Paint and
slightly translucent specimens will affect their measurement.
Related Coatings, Materials, and Applications and is the direct responsibility of
Subcommittee D01.26 on Optical Properties. Use the most applicable of the backing techniques that follow.
Current edition approved Oct. 31, 1980. Published December 1980.
Annual Book of ASTM Standards, Vol 06.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.