ASTM E2022-08
(Practice)Standard Practice for Calculation of Weighting Factors for Tristimulus Integration
Standard Practice for Calculation of Weighting Factors for Tristimulus Integration
SIGNIFICANCE AND USE
This practice is intended to provide a method that will yield uniformity of calculations used in making, matching, or controlling colors of objects. This uniformity is accomplished by providing a method for calculation of weighting factors for tristimulus integration consistent with the methods utilized to obtain the weighting factors for common illuminant-observer combinations contained in Practice E 308.
This practice should be utilized by persons desiring to calculate a set of weighting factors for tristimulus integration who have custom source, or illuminant spectral power distributions, or custom observer response functions.
This practice assumes that the measurement interval is equal to the spectral bandwidth integral when applying correction for bandwidth.
SCOPE
1.1 This practice describes the method to be used for calculating tables of weighting factors for tristimulus integration using custom spectral power distributions of illuminants or sources, or custom color-matching functions.
1.2 This practice provides methods for calculating tables of values for use with spectral reflectance or transmittance data, which are corrected for the influences of finite bandpass. In addition, this practice provides methods for calculating weighting factors from spectral data which has not been bandpass corrected. In the latter case, a correction for the influence of bandpass on the resulting tristimulus values is built in to the tristimulus integration through the weighting factors.
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 and health practices and determine the applicability of regulatory limitations prior to its use.
General Information
Relations
Buy Standard
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: E2022 – 08
Standard Practice for
1
Calculation of Weighting Factors for Tristimulus Integration
This standard is issued under the fixed designation E2022; 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 3.2 Definitions of Terms Specific to This Standard:
3.2.1 illuminant, n—real or ideal radiant flux, specified by
1.1 This practice describes the method to be used for
its spectral distribution over the wavelengths that, in illuminat-
calculating tables of weighting factors for tristimulus integra-
ing objects, can affect their perceived colors.
tionusingcustomspectralpowerdistributionsofilluminantsor
3.2.2 source, n—an object that produces light or other
sources, or custom color-matching functions.
radiant flux, or the spectral power distribution of that light.
1.2 This practice provides methods for calculating tables of
3.2.2.1 Discussion—A source is an emitter of visible radia-
values for use with spectral reflectance or transmittance data,
tion. An illuminant is a table of agreed spectral power
which are corrected for the influences of finite bandpass. In
distribution that may represent a source; thus, IlluminantAis a
addition,thispracticeprovidesmethodsforcalculatingweight-
standard spectral power distribution and Source A is the
ing factors from spectral data which has not been bandpass
physical representation of that distribution. Illuminant D65 is a
corrected. In the latter case, a correction for the influence of
standard illuminant that represents average north sky daylight
bandpass on the resulting tristimulus values is built in to the
but has no representative source.
tristimulus integration through the weighting factors.
3.2.3 spectral power distribution, SPD, S(l),
1.3 The values stated in SI units are to be regarded as
n—specification of an illuminant by the spectral composition
standard. No other units of measurement are included in this
of a radiometric quantity, such as radiance or radiant flux, as a
standard.
function of wavelength.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Summary of Practice
responsibility of the user of this standard to establish appro-
4.1 CIE color-matching functions are standardized at 1-nm
priate safety and health practices and determine the applica-
wavelength intervals. Tristimulus integration by multiplication
bility of regulatory limitations prior to its use.
of abridged spectral data into sets of weighting factors occurs
2. Referenced Documents at larger intervals, typically 10-nm or 20-nm; therefore, inter-
2 mediate 1-nm interval spectral data are missing, but needed.
2.1 ASTM Standards:
4.2 Lagrange interpolating coefficients are calculated for the
E284 Terminology of Appearance
missing wavelengths. The Lagrange coefficients, when multi-
E308 Practice for Computing the Colors of Objects by
plied into the appropriate measured spectral data, interpolate
Using the CIE System
the abridged spectrum to 1-nm interval. The 1-nm interval
2.2 CIE Standard:
3
spectrum is then multiplied into the CIE 1-nm color-matching
CIE Standard S 002 Colorimetric Observers
data, and into the source spectral power distribution. Each
3. Terminology
separate term of this multiplication is collected into a value
associated with a measured spectral wavelength, thus forming
3.1 Definitions—Appearance terms in this practice are in
weighting factors for tristimulus integration.
accordance with Terminology E284.
4.3 A correction may be applied to the resulting table of
weighting factors to incorporate a correction for the spectral
1
This practice is under the jurisdiction of ASTM Committee E12 on Color and
data’s bandpass dependence.
Appearance and is the direct responsibility of Subcommittee E12.04 on Color and
Appearance Analysis.
5. Significance and Use
Current edition approved Dec. 1, 2008. Published January 2009. Originally
´1
approved in 1999. Last previous edition approved in 2006 as E2022 - 06 . DOI:
5.1 This practice is intended to provide a method that will
10.1520/E2022-08.
2 yield uniformity of calculations used in making, matching, or
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
controlling colors of objects. This uniformity is accomplished
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
by providing a method for calculation of weighting factors for
the ASTM website.
tristimulus integration consistent with the methods utilized to
3
Available from USNC-CIE
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
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.
´1
Designation:E2022–06 Designation: E 2022 – 08
Standard Practice for
1
Calculation of Weighting Factors for Tristimulus Integration
This standard is issued under the fixed designation E 2022; 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
´ NOTE—The units statement in subsection 1.3 was added editorially in May 2008.
1. Scope
1.1 This practice describes the method to be used for calculating tables of weighting factors for tristimulus integration using
custom spectral power distributions of illuminants or sources, or custom color-matching functions.
1.2 This practice provides methods for calculating tables of values for use with spectral reflectance or transmittance data, which
arecorrectedfortheinfluencesoffinitebandpass.Inaddition,thispracticeprovidesmethodsforcalculatingweightingfactorsfrom
spectral data which has not been bandpass corrected. In the latter case, a correction for the influence of bandpass on the resulting
tristimulus values is built in to the tristimulus integration through the weighting factors.
1.3The1.3 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 and health practices and determine the applicability of regulatory
limitations prior to its use.
2. Referenced Documents
2
2.1 ASTM Standards:
E 284 Terminology of Appearance
E 308 Practice for Computing the Colors of Objects by Using the CIE System
2.2 CIE Standard:
3
CIE Standard S 002 Colorimetric Observers
3. Terminology
3.1 Definitions—Appearance terms in this practice are in accordance with Terminology E 284.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 illuminant, n—real or ideal radiant flux, specified by its spectral distribution over the wavelengths that, in illuminating
objects, can affect their perceived colors.
3.2.2 source, n—an object that produces light or other radiant flux, or the spectral power distribution of that light.
3.2.2.1 Discussion—A source is an emitter of visible radiation. An illuminant is a table of agreed spectral power distribution
that may represent a source; thus, IlluminantAis a standard spectral power distribution and SourceAis the physical representation
of that distribution. Illuminant D65 is a standard illuminant that represents average north sky daylight but has no representative
source.
3.2.3 spectral power distribution, SPD, S(l), n—specification of an illuminant by the spectral composition of a radiometric
quantity, such as radiance or radiant flux, as a function of wavelength.
4. Summary of Practice
4.1 CIE color-matching functions are standardized at 1-nm wavelength intervals. Tristimulus integration by multiplication of
abridged spectral data into sets of weighting factors occurs at larger intervals, typically 10-nm or 20-nm; therefore, intermediate
1
This practice is under the jurisdiction of ASTM Committee E12 on Color and Appearance and is the direct responsibility of Subcommittee E12.04 on Color and
Appearance Analysis.
Current edition approved July 1, 2006. Published July 2006. Originally approved in 1999. Last previous edition approved in 2001 as E2022-01.
´1
Current edition approved Dec. 1, 2008. Published January 2009. Originally approved in 1999. Last previous edition approved in 2006 as E 2022 - 06 .
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM 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.
3
Available from USNC-CIE Publications Office, TLA Lighting Consultants, 7 Pond Street, Salem, MA 01970.
3
Available from USNC-CIE Publications Office (International Commission on Illumination), C/oThomas M. Lemons,TLA-Lighting Consultants, Inc., 7 Pond St., Salem,
MA 01970, http://www.cie-usnc.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------------------
E2022–08
1-nm interval spectral data are missing, but needed.
4.2 Lagrange interpolating coefficients are calculated for the mi
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
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.
´1
Designation:E2022–06 Designation: E 2022 – 08
Standard Practice for
1
Calculation of Weighting Factors for Tristimulus Integration
This standard is issued under the fixed designation E 2022; 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
´ NOTE—The units statement in subsection 1.3 was added editorially in May 2008.
1. Scope
1.1 This practice describes the method to be used for calculating tables of weighting factors for tristimulus integration using
custom spectral power distributions of illuminants or sources, or custom color-matching functions.
1.2 This practice provides methods for calculating tables of values for use with spectral reflectance or transmittance data, which
arecorrectedfortheinfluencesoffinitebandpass.Inaddition,thispracticeprovidesmethodsforcalculatingweightingfactorsfrom
spectral data which has not been bandpass corrected. In the latter case, a correction for the influence of bandpass on the resulting
tristimulus values is built in to the tristimulus integration through the weighting factors.
1.3The1.3 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 and health practices and determine the applicability of regulatory
limitations prior to its use.
2. Referenced Documents
2
2.1 ASTM Standards:
E 284 Terminology of Appearance
E 308 Practice for Computing the Colors of Objects by Using the CIE System
2.2 CIE Standard:
3
CIE Standard S 002 Colorimetric Observers
3. Terminology
3.1 Definitions—Appearance terms in this practice are in accordance with Terminology E 284.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 illuminant, n—real or ideal radiant flux, specified by its spectral distribution over the wavelengths that, in illuminating
objects, can affect their perceived colors.
3.2.2 source, n—an object that produces light or other radiant flux, or the spectral power distribution of that light.
3.2.2.1 Discussion—A source is an emitter of visible radiation. An illuminant is a table of agreed spectral power distribution
that may represent a source; thus, IlluminantAis a standard spectral power distribution and SourceAis the physical representation
of that distribution. Illuminant D65 is a standard illuminant that represents average north sky daylight but has no representative
source.
3.2.3 spectral power distribution, SPD, S(l), n—specification of an illuminant by the spectral composition of a radiometric
quantity, such as radiance or radiant flux, as a function of wavelength.
4. Summary of Practice
4.1 CIE color-matching functions are standardized at 1-nm wavelength intervals. Tristimulus integration by multiplication of
abridged spectral data into sets of weighting factors occurs at larger intervals, typically 10-nm or 20-nm; therefore, intermediate
1
This practice is under the jurisdiction of ASTM Committee E12 on Color and Appearance and is the direct responsibility of Subcommittee E12.04 on Color and
Appearance Analysis.
Current edition approved July 1, 2006. Published July 2006. Originally approved in 1999. Last previous edition approved in 2001 as E2022-01.
´1
Current edition approved Dec. 1, 2008. Published January 2009. Originally approved in 1999. Last previous edition approved in 2006 as E 2022 - 06 .
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM 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.
3
Available from USNC-CIE Publications Office, TLA Lighting Consultants, 7 Pond Street, Salem, MA 01970.
3
Available from USNC-CIE Publications Office (International Commission on Illumination), C/oThomas M. Lemons,TLA-Lighting Consultants, Inc., 7 Pond St., Salem,
MA 01970, http://www.cie-usnc.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------------------
E2022–08
1-nm interval spectral data are missing, but needed.
4.2 Lagrange interpolating coefficients are calculated for the mi
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.