ASTM E1348-22

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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.
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Designation: E1348 − 15 E1348 − 22
Standard Test Method for
Transmittance and Color by Spectrophotometry Using
Hemispherical Geometry
This standard is issued under the fixed designation E1348; 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.
ε NOTE—Equation 1 was editorially corrected in September 2016.
1. Scope
1.1 This test method describes the instrumental measurement of the transmission properties and color of object-color specimens
by the use of a spectrophotometer or spectrocolorimeter with a hemispherical optical measuring system, such as an integrating
sphere.
1.2 This test method is generally suitable for all fully transparent specimens without regard for the specimen position relative to
the transmission port of the instrument. Translucent specimens, however, must be placed flush against the transmission port of the
sphere.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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 safety, health, and healthenvironmental 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:
D1003 Test Method for Haze and Luminous Transmittance of Transparent Plastics
D2244 Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates
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
E805 Practice for Identification of Instrumental Methods of Color or Color-Difference Measurement of Materials
E1164 Practice for Obtaining Spectrometric Data for Object-Color Evaluation
This test method is under the jurisdiction of ASTM Committee E12 on Color and Appearance and is the direct responsibility of Subcommittee E12.02 on
Spectrophotometry and Colorimetry.
Current edition approved Nov. 1, 2015Oct. 1, 2022. Published November 2015November 2022. Originally approved in 1990. Last previous edition approved in 20112015
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as E1348 – 1115 . DOI: 10.1520/E1348-15E01.10.1520/E1348-22.
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.
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E1348 − 22
3. Terminology
3.1 Definitions:
3.1.1 The definitions in Guide E179, Terminology E284, and Practice E1164 are applicable to this test method.
4. Summary of Test Method
4.1 This test method provides a procedure for measuring the transmittance of transmitting specimens by using a spectrophotometer
or spectrocolorimeter equipped with a hemispherical optical measuring system such as an integrating sphere.
4.2 This test method includes procedures for calibrating the instrument and for selecting specimens suitable for precision
measurement.
4.3 This test method is satisfactory for all fully transparent specimens with plane and parallel surfaces. When possible, the user
should select the position of the specimen in the transmission compartment to provide either essentially total or essentially regular
transmittance, depending on the end use of the measured data.
4.4 Accurate measurement of translucent specimens requires that the specimen be placed flush against the transmission port of the
integrating sphere (see Practice E1164, 8.1.4).
4.5 Most modern spectrophotometers have the capacity to compute the color coordinates of the specimen during the measurement.
When this is the case, the user of this test method must select the color scale, illuminant and observer (see the Procedure section
in Practice E308, Section 6).
5. Significance and Use
5.1 The most direct and accessible methods for obtaining the color coordinates of object colors are by instrumental measurement
using spectrophotometers or colorimeters with either hemispherical or bidirectional optical measuring systems. This test method
provides procedures for such measurement by transmittance spectrophotometry using a hemispherical optical measuring system.
5.2 This test method is especially suitable for measurement of the following types of specimens (see also Guide E179 and Practice
E805):
5.2.1 Fully transparent specimens (free from turbidity, haze, or translucency), and
5.2.2 Translucent or hazy specimens, provided that the specimen can be placed flush against the transmission port of the
integrating sphere.
5.3 This test method is not recommended for measurement of retroreflective transparent or translucent specimens, or samples that
are fluorescent.
6. Apparatus
6.1 Spectrophotometer or Spectrocolorimeter, designed for the measurement of color coordinates of transmitting specimens by use
of integrating-sphere geometry.
6.2 Calibration Standards, either supplied by the instrument manufacturer or obtained separately, as follows (see Practice E1164,
Section 10):
6.2.1 White Tile or Pressed-Powder Reflectance Standard, to be placed at the reflection port of the integrating sphere (mandatory).
6.2.1 Calibration Standards, for (1) for setting or verifying zero on the photometric scale; scale, and (2) verifying the wavelength
scale, and (for setting the full scale standardization if3) evaluating stray light (optional). the instrument has a reflectance port.
6.2.2 Verification Standards (recommended)(recommended), for (1) verifying the wavelength scale, (2) verifying linearity, and (3)
verifying stray light (see Practice E1164, 10.5).
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7. Test Specimen
7.1 For highest precision and accuracy, select specimens with the following properties (see Practice E1164, Section 9):
7.1.1 High material uniformity and freedom from blemishes in the area to be measured, and
7.1.2 Specimens that have two essentially plane and parallel surfaces, and that have a standard thickness, if one is defined.
8. Calibration and Verification
8.1 Calibrate or verify the calibration of the following quantities (see Practice E1164, Section 10):
8.1.1 Zero setting of the transmittance scale (mandatory),
8.1.2 Wavelength scale (recommended), and
8.1.3 Stray-light level (optional).
8.1 Calibrate the full-scale value of the transmittance scale of theor verify the calibration of th
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