ASTM E308-99

Standard Practice for Computing the Colors of Objects by Using the CIE System

SCOPE
1.1 This practice provides the values and practical computation procedures needed to obtain CIE tristimulus values from spectral reflectance, transmittance, or radiance data for object-color specimens.
1.2 Procedures and tables of standard values are given for computing from spectral measurements the CIE tristimulus values X, Y, Z, and chromaticity coordinates x, y for the CIE 1931 standard observer and X10, Y10, Z 10 and x10. y10 for the CIE 1964 supplementary standard observer.
1.3 Standard values are included for the spectral power of six CIE standard illuminants and three CIE recommended fluorescent illuminants.
1.4 Procedures are included for cases in which data are available only in more limited wavelength ranges than those recommended, or for a measurement interval wider than that recommended by the CIE. This practice is applicable to spectral data obtained according to Practice E 1164 with 1-, 5-, 10-, or 20-nm measurement interval.
1.5 Procedures are included for cases in which the spectral data are, and those in which they are not, corrected for bandpass dependence. For the uncorrected cases, it is assumed that the spectral bandpass of the instrument used to obtain the data was approximately equal to the measurement interval and was triangular in shape. These choices are believed to correspond to the most widely used industrial practice.
1.6 This practice includes procedures for conversion of results to color spaces that are part of the CIE system, such as CIELAB and CIELUV (3). Equations for calculating color differences in these and other systems are given in Test Method D 2244.
1.7 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-Aug-2001
• ICS: 17.180.20 - Colours and measurement of light
• Technical Committee: E12 - Color and Appearance
• Drafting Committee: E12.04 - Color and Appearance Analysis

Relations

• Replaced By: ASTM E308-01 - Standard Practice for Computing the Colors of Objects by Using the CIE System
• Effective Date: 10-Aug-2001
• Referred By: ASTM D8515-23 - Standard Test Method for Color of Rosin in Solution (Instrumental Determination of Gardner Color)
• Effective Date: 10-Aug-2001
• Referred By: ASTM D1562-22 - Standard Classification System and Basis for Specification for Cellulose Acetate Propionate Molding and Extrusion Compounds (CAP)
• Effective Date: 10-Aug-2001
• Referred By: ASTM D5382-02(2017) - Standard Guide to Evaluation of Optical Properties of Powder Coatings
• Effective Date: 10-Aug-2001
• Referred By: ASTM D6166-12(2022) - Standard Test Method for Color of Pine Chemicals and Related Products (Instrumental Determination of Gardner Color)
• Effective Date: 10-Aug-2001
• Referred By: ASTM E313-20 - Standard Practice for Calculating Yellowness and Whiteness Indices from Instrumentally Measured Color Coordinates
• Effective Date: 10-Aug-2001
• Referred By: ASTM E810-20 - Standard Test Method for Coefficient of Retroreflection of Retroreflective Sheeting Utilizing the Coplanar Geometry
• Effective Date: 10-Aug-2001
• Referred By: ASTM D8514/D8514M-23 - Standard Specification for Flexible, Retroreflective Sheeting for Use in High Visibility Vehicle Markings
• Effective Date: 10-Aug-2001
• Referred By: ASTM E1336-11(2017) - Standard Test Method for Obtaining Colorimetric Data From a Visual Display Unit by Spectroradiometry
• Effective Date: 10-Aug-2001
• Referred By: ASTM D2851-15(2023) - Standard Specification for Liquid Optical Adhesive
• Effective Date: 10-Aug-2001
• Referred By: ASTM D1544-04(2023) - Standard Test Method for Color of Transparent Liquids (Gardner Color Scale)
• Effective Date: 10-Aug-2001
• Referred By: ASTM D6290-19 - Standard Test Method for Color Determination of Plastic Pellets
• Effective Date: 10-Aug-2001
• Referred By: ASTM E2022-16(2021) - Standard Practice for Calculation of Weighting Factors for Tristimulus Integration
• Effective Date: 10-Aug-2001
• Referred By: ASTM D8163-18(2023) - Standard Test Method for Determination of Strength of Colorants and Bases for Architectural, Marine, Maintenance, Commercial, and Industrial Coatings
• Effective Date: 10-Aug-2001
• Referred By: ASTM D5531-17(2023) - Standard Guide for Preparation, Maintenance, and Distribution of Physical Product Standards for Color and Geometric Appearance of Coatings
• Effective Date: 10-Aug-2001

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: E 308 – 99
Standard Practice for
1
Computing the Colors of Objects by Using the CIE System
This standard is issued under the fixed designation E 308; 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.
This standard has been approved for use by agencies of the Department of Defense.
INTRODUCTION
Standard tables (Tables 1-4) of color matching functions and illuminant spectral power distributions
have since 1931 been defined by the CIE, but the CIE has eschewed the role of preparing tables of
tristimulus weighting factors for the convenient calculation of tristimulus values. There have
subsequently appeared numerous compilations of tristimulus weighting factors in the literature with
disparity of data resulting from, for example, different selections of wavelength intervals and methods
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of truncating abbreviated wavelength ranges. In 1970, Foster et al. (1) proposed conventions to
standardize these two features, and Stearns (2) published a more complete set of tables. Stearns’ work
and later publications such as the 1985 revision of E 308 have greatly reduced the substantial
variations in methods for tristimulus computation that existed several decades ago.
The disparities among earlier tables were largely caused by the introduction of computations based
on 20-nm wavelength intervals. With the increasing precision of modern instruments, there is a
likelihood of a need for tables for narrower wavelength intervals. Stearns’ tables, based on a 10-nm
interval, did not allow the derivation of consistent tables with wavelength intervals less than 10 nm.
The 1-nm table must be designated the basic table if others with greater wavelength intervals are to
have the same white point, and this was the reason for the 1985 revision of E308, resulting in tables
that are included in the present revision as Tables 5.
The 1994 revision was made in order to introduce to the user a method of reducing the dependence
of the computed tristimulus values on the bandpass of the measuring instrument, using methods that
are detailed in this practice. These changes, however, lead to tables (Tables 6 in this practice) that are
substantially different from the Tables 5 that have been in use since 1985. There is accordingly a
danger, if the new tables are introduced but not universally adopted, that there may again be, perhaps
for several decades, a significant disparity among the tables of tristimulus weighting factors commonly
used. It is highly desirable that this should be avoided.
1. Scope six CIE standard illuminants and three CIE recommended
fluorescent illuminants.
1.1 This practice provides the values and practical compu-
1.4 Procedures are included for cases in which data are
tation procedures needed to obtain CIE tristimulus values from
available only in more limited wavelength ranges than those
spectral reflectance, transmittance, or radiance data for object-
recommended, or for a measurement interval wider than that
color specimens.
recommended by the CIE. This practice is applicable to
1.2 Procedures and tables of standard values are given for
spectral data obtained according to Practice E 1164 with 1-, 5-,
computing from spectral measurements the CIE tristimulus
10-, or 20-nm measurement interval.
values X, Y, Z, and chromaticity coordinates x, y for the CIE
1.5 Procedures are included for cases in which the spectral
1931 standard observer and X ,Y ,Z and x .y for the
10 10 10 10 10
data are, and those in which they are not, corrected for
CIE 1964 supplementary standard observer.
bandpass dependence. For the uncorrected cases, it is assumed
1.3 Standard values are included for the spectral power of
that the spectral bandpass of the instrument used to obtain the
data was approximately equal to the measurement interval and
1
This practice is under the jurisdiction of ASTM Committee E-12 on Color and
was triangular in shape. These choices are believed to corre-
Appearanceand is the direct responsibility of Subcommittee E12.04 on Color and
spond to the most widely used industrial practice.
Appearance Analysis.
Current edition approved June 10, 1999. Published October 1999. Originally 1.6 This practice includes procedures for conversion of
published as E 308 – 66. Last previous edition E 308 – 96.
results to color spaces that are part of the CIE system, such as
2
The boldface numbers in parentheses refer to the list of references at the end of
CIELAB and CIELUV (3). Equations for calculating color
this practice.
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