ASTM C1649-08
(Practice)Standard Practice for Instrumental Transmittance Measurement of Color for Flat Glass, Coated and Uncoated
Standard Practice for Instrumental Transmittance Measurement of Color for Flat Glass, Coated and Uncoated
SIGNIFICANCE AND USE
Color measurement quantifies the transmitted color for glass. The user defines an acceptable range of color appropriate for the end use. A typical quality concern for transmittance color measurement of glass products is verification of lot-to-lot color consistency for end-user acceptance.
If the transmitted color of a glass product is consistent from lot-to-lot and within agreed supplier-buyer acceptance criteria, the product’s color is expected to be consistent and acceptable for end-use.
SCOPE
1.1 This practice provides guidelines for the instrumental transmittance measurement of the color of coated and uncoated transparent glass. See Terminology E 284.
1.2 The practice specifically excludes fluorescent and iridescent samples.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
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 and health practices and determine the applicability of regulatory limitations prior to use.
General Information
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: C1649 − 08
StandardPractice for
Instrumental Transmittance Measurement of Color for Flat
Glass, Coated and Uncoated
This standard is issued under the fixed designation C1649; 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 2.2 CIE Standard:
CIE 15:2004 Colorimetry
1.1 This practice provides guidelines for the instrumental
transmittancemeasurementofthecolorofcoatedanduncoated
3. Summary of Practice
transparent glass. See Terminology E284.
3.1 The color of transparent glass is measured in the total
1.2 The practice specifically excludes fluorescent and iri-
transmittance mode on a CIE-conforming diffuse instrument.
descent samples.
(See Guide E179 and Test Method E1348.) The glass color is
1.3 The values stated in SI units are to be regarded as the
expressed in CIE tristimulus values based on spectral transmit-
standard. The values given in parentheses are for information
tance measurements over the full CIE spectral range of 350 –
only.
780 nm with a maximum 10-nm band pass. (See CIE 15:2004
and Practice E308.) For color measurement, use of a truncated
1.4 This standard does not purport to address all of the
spectral range of 400 – 700 nm is acceptable. (See CIE
safety concerns, if any, associated with its use. It is the
15:2004.) Further information on the UV absorbing character-
responsibility of the user of this standard to establish appro-
istics of the glass or glass coating, or both, may be determined
priate safety and health practices and determine the applica-
byexaminingthespectraldatainthe350-400nmrange.Ifthe
bility of regulatory limitations prior to use.
instrument allows spectral measurement above 700 nm, useful
information on the IR transmittance characteristics of the glass
2. Referenced Documents
or glass coating may also be determined. If coatings are
2.1 ASTM Standards:
present, they are assumed to reflect and partially transmit light.
D2244 Practice for Calculation of Color Tolerances and
Color Differences from Instrumentally Measured Color
4. Significance and Use
Coordinates
4.1 Color measurement quantifies the transmitted color for
E284 Terminology of Appearance
glass.Theuserdefinesanacceptablerangeofcolorappropriate
E179 Guide for Selection of Geometric Conditions for
for the end use. A typical quality concern for transmittance
Measurement of Reflection and Transmission Properties
color measurement of glass products is verification of lot-to-lot
of Materials (Withdrawn 2012)
color consistency for end-user acceptance.
E308 PracticeforComputingtheColorsofObjectsbyUsing
the CIE System
4.2 If the transmitted color of a glass product is consistent
E1164 PracticeforObtainingSpectrometricDataforObject- from lot-to-lot and within agreed supplier-buyer acceptance
Color Evaluation
criteria, the product’s color is expected to be consistent and
E1348 Test Method for Transmittance and Color by Spec- acceptable for end-use.
trophotometry Using Hemispherical Geometry
5. Apparatus
5.1 For color measurements, a CIE-conforming diffuse
This practice is under the jurisdiction of ASTM Committee C14 on Glass and sphere instrument capable of making transmission measure-
Glass Products and is the direct responsibility of Subcommittee C14.11 on Optical
ments in the total transmittance mode is required.
Properties.
Current edition approved Jan. 1, 2008. Published January 2008. DOI: 10.1520/ 5.2 Inaddition,adeviceformountingtheglasssampleflush
C1649-08.
at the transmission port is required.
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. Available from U.S. National Committee of the CIE (International Commission
The last approved version of this historical standard is referenced on on Illumination), C/o Thomas M. Lemons, TLA-Lighting Consultants, Inc., 7 Pond
www.astm.org. St., Salem, MA 01970, http://www.cie-usnc.org.
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C1649 − 08
5.3 The instrument and associated color quality software/ 9.2 At a minimum, scan the sample over the range of
firmware shall be capable of converting measured spectral wavelengths required for measurement. Two scans with a 90º
transmittance data to CIE L*, a* b*; Hunter L, a, b; or Y, x, y rotation of the samples are preferable. If practical and possible,
values calculated for CIE illuminant D65 and the CIE 1964 10 scan at least one other area of the sample as well.
degree standard observer. (See Practice E1164.) Any of those
9.3 Correction for reflection loss of uncoated glass (op-
mappings will serve as a full numerical color descriptor. (See
tional):
Practice E308.) CIE Y transmittance can also serve as an
9.3.1 Because of historical practices, some industries apply
over-all indicator of transmission. For other illuminant/
a correction for reflection loss to the transmittance and others
observer combinations, see Practice E308 for guidance in use.
do not. As a result, specifications based on transmitted color
For effective communication of color values between
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