ASTM E2729-16(2021)
(Practice)Standard Practice for Rectification of Spectrophotometric Bandpass Differences
Standard Practice for Rectification of Spectrophotometric Bandpass Differences
SIGNIFICANCE AND USE
5.1 Failure to make such a rectification introduces differences from the true value of the spectrum of about 0.02 to 0.4 ΔE*ab units. All users are required to make a rectification of such bandpass differences. It is especially incumbent upon writers of computer programs whose function it is to acquire such spectra from instruments to see that a competent rectification is implemented in the program before any additional processing of the spectrum, or calculations involving the spectrum are accomplished, or before the spectrum is made available to a user.
5.2 Legacy measuring systems are explicitly exempted from any requirements for retrofitting of hardware or software and may continue to utilize previously accepted methods of making the bandwidth rectification.
SCOPE
1.1 This standard outlines the methods that can be used to deconvolve, at least partially, the spectral bandpass differences of raw spectral data acquired by abridged spectrophotometry. Such differences are introduced because the spectral passband must be of significant bandwidth to allow sufficient energy to reach the detector. On the other hand, the spectral data that should be reported is that of a virtual 1-nm bandwidth spectrum in order to be useful in the CIE method of tristimulus integration which involves 1-nm summation.
1.2 The standard establishes practices for whether, when, and how a bandpass rectification should be made to any reflectance or transmittance spectrum acquired by abridged spectrophotometry.
1.3 It is applicable where the shape of the passband is triangular and the bandwidth is equal to the measurement interval between passbands. Information is provided in Section 7 for users when that condition is not satisfactorily met.
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, health, and environmental 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.
General Information
- Status
- Published
- Publication Date
- 31-May-2021
- Technical Committee
- E12 - Color and Appearance
- Drafting Committee
- E12.04 - Color and Appearance Analysis
Relations
- Effective Date
- 01-May-2017
- Effective Date
- 01-Apr-2015
- Effective Date
- 01-Nov-2013
- Effective Date
- 01-Jun-2013
- Effective Date
- 01-Jan-2013
- Effective Date
- 01-Jul-2012
- Effective Date
- 01-Jul-2012
- Effective Date
- 01-Jun-2009
- Effective Date
- 01-Jan-2009
- Effective Date
- 01-Dec-2008
- Effective Date
- 01-Aug-2008
- Effective Date
- 15-Jul-2007
- Effective Date
- 01-Dec-2006
- Effective Date
- 01-Dec-2006
- Effective Date
- 15-Jul-2006
Overview
ASTM E2729-16(2021), Standard Practice for Rectification of Spectrophotometric Bandpass Differences, sets forth procedures for correcting bandpass differences in spectral data obtained via abridged spectrophotometry. The standard is maintained by ASTM International and aligns with internationally recognized principles for standardization. Its primary goal is to ensure that spectral reflectance and transmittance data from instruments with non-ideal passbands are suitable for accurate colorimetric calculations - notably, in compliance with the CIE method of tristimulus integration.
This standard is particularly important because failure to perform this bandpass rectification can introduce inaccuracies of 0.02 to 0.4 ΔE*ab units in the spectral data, potentially impacting color quality assessments, product comparisons, and scientific measurements.
Key Topics
- Bandpass Rectification: Guidance on when, whether, and how to correct spectral data for bandpass differences, focusing on data acquired from abridged spectrophotometry.
- Applicability: Designed for spectrophotometers with triangular passbands, where the bandwidth equals the interval between measurements. Recommendations are provided for other passband types.
- Procedures for Correction: The standard details step-by-step methods for rectifying raw spectrum data, specifying actions for first, last, and interior passbands.
- Impact on Data Quality: Establishes that proper rectification significantly reduces color measurement errors and improves the reliability of spectral data used in industrial and research applications.
- Programmatic Implementation: Stresses the role of software and computer program writers in ensuring rectification is properly applied prior to any further spectrum processing or user access.
- Legacy Systems: Provides explicit exemptions for legacy measuring systems, allowing the continued use of previously accepted correction methods without mandatory retrofitting.
Applications
ASTM E2729 is essential for professionals and organizations working with spectrophotometric data, especially in fields such as color science, quality control, and material analysis. Typical applications include:
- Quality Control in Manufacturing: Ensuring that color measurements of products are accurate and consistent, crucial in textiles, plastics, paints, and coatings industries.
- Research and Development: Supporting the generation of high-fidelity spectral data for scientific studies and technological advancements in material sciences.
- Instrument and Software Development: Guiding manufacturers of spectrophotometers and associated software on the necessary steps for automatic or user-invoked bandpass rectification.
- Data File Management: Recommending best practices for the bulk or individual rectification of legacy spectral data files, as well as database flagging to prevent re-processing.
Implementing this standard promotes interoperability, regulatory compliance, and customer confidence due to improved data integrity.
Related Standards
Several standards and references are closely connected to ASTM E2729, enhancing its application:
- ASTM E308 – Practice for Computing the Colors of Objects by Using the CIE System: Describes colorimetric calculations where 1-nm bandwidth data are critical.
- ASTM E284 – Terminology of Appearance: Provides definitions for terms used in appearance measurement standards.
- CIE Method of Tristimulus Integration: A foundational method for deriving colorimetric values from spectral data.
By following ASTM E2729-16(2021) alongside these related standards, organizations ensure comprehensive and internationally recognized approaches to spectrophotometric data processing and color measurement accuracy.
Keywords: bandpass rectification, spectrophotometric correction, spectral deconvolution, color measurement standard, spectral data accuracy, ASTM E2729, CIE tristimulus integration, reflectance spectrum, transmittance spectrum
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Frequently Asked Questions
ASTM E2729-16(2021) is a standard published by ASTM International. Its full title is "Standard Practice for Rectification of Spectrophotometric Bandpass Differences". This standard covers: SIGNIFICANCE AND USE 5.1 Failure to make such a rectification introduces differences from the true value of the spectrum of about 0.02 to 0.4 ΔE*ab units. All users are required to make a rectification of such bandpass differences. It is especially incumbent upon writers of computer programs whose function it is to acquire such spectra from instruments to see that a competent rectification is implemented in the program before any additional processing of the spectrum, or calculations involving the spectrum are accomplished, or before the spectrum is made available to a user. 5.2 Legacy measuring systems are explicitly exempted from any requirements for retrofitting of hardware or software and may continue to utilize previously accepted methods of making the bandwidth rectification. SCOPE 1.1 This standard outlines the methods that can be used to deconvolve, at least partially, the spectral bandpass differences of raw spectral data acquired by abridged spectrophotometry. Such differences are introduced because the spectral passband must be of significant bandwidth to allow sufficient energy to reach the detector. On the other hand, the spectral data that should be reported is that of a virtual 1-nm bandwidth spectrum in order to be useful in the CIE method of tristimulus integration which involves 1-nm summation. 1.2 The standard establishes practices for whether, when, and how a bandpass rectification should be made to any reflectance or transmittance spectrum acquired by abridged spectrophotometry. 1.3 It is applicable where the shape of the passband is triangular and the bandwidth is equal to the measurement interval between passbands. Information is provided in Section 7 for users when that condition is not satisfactorily met. 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, health, and environmental 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.
SIGNIFICANCE AND USE 5.1 Failure to make such a rectification introduces differences from the true value of the spectrum of about 0.02 to 0.4 ΔE*ab units. All users are required to make a rectification of such bandpass differences. It is especially incumbent upon writers of computer programs whose function it is to acquire such spectra from instruments to see that a competent rectification is implemented in the program before any additional processing of the spectrum, or calculations involving the spectrum are accomplished, or before the spectrum is made available to a user. 5.2 Legacy measuring systems are explicitly exempted from any requirements for retrofitting of hardware or software and may continue to utilize previously accepted methods of making the bandwidth rectification. SCOPE 1.1 This standard outlines the methods that can be used to deconvolve, at least partially, the spectral bandpass differences of raw spectral data acquired by abridged spectrophotometry. Such differences are introduced because the spectral passband must be of significant bandwidth to allow sufficient energy to reach the detector. On the other hand, the spectral data that should be reported is that of a virtual 1-nm bandwidth spectrum in order to be useful in the CIE method of tristimulus integration which involves 1-nm summation. 1.2 The standard establishes practices for whether, when, and how a bandpass rectification should be made to any reflectance or transmittance spectrum acquired by abridged spectrophotometry. 1.3 It is applicable where the shape of the passband is triangular and the bandwidth is equal to the measurement interval between passbands. Information is provided in Section 7 for users when that condition is not satisfactorily met. 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, health, and environmental 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.
ASTM E2729-16(2021) is classified under the following ICS (International Classification for Standards) categories: 71.040.50 - Physicochemical methods of analysis. The ICS classification helps identify the subject area and facilitates finding related standards.
ASTM E2729-16(2021) has the following relationships with other standards: It is inter standard links to ASTM E308-17, ASTM E308-15, ASTM E284-13b, ASTM E284-13a, ASTM E284-13, ASTM E308-12, ASTM E284-12, ASTM E284-09a, ASTM E284-09, ASTM E308-08, ASTM E284-08, ASTM E284-07, ASTM E308-06, ASTM E284-06b, ASTM E284-06a. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
ASTM E2729-16(2021) is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
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.
Designation: E2729 −16 (Reapproved 2021)
Standard Practice for
Rectification of Spectrophotometric Bandpass Differences
This standard is issued under the fixed designation E2729; 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 E308 PracticeforComputingtheColorsofObjectsbyUsing
the CIE System
1.1 This standard outlines the methods that can be used to
deconvolve, at least partially, the spectral bandpass differences
3. Terminology
of raw spectral data acquired by abridged spectrophotometry.
3.1 Definitions—For definition of terms used in this
Such differences are introduced because the spectral passband
practice, refer to Terminology E284.
must be of significant bandwidth to allow sufficient energy to
reach the detector. On the other hand, the spectral data that
3.2 Definitions of Terms Specific to This Standard:
shouldbereportedisthatofavirtual1-nmbandwidthspectrum
3.2.1 virtual 1-nm bandwidth spectrum, n—spectral data
in order to be useful in the CIE method of tristimulus
that have been corrected by numerical methods so as to match
integration which involves 1-nm summation.
ascloselyaspossibleaspectrumfromthesamesourcebutwith
a putative bandwidth of 1 nm.
1.2 The standard establishes practices for whether, when,
and how a bandpass rectification should be made to any
4. Summary of Practice
reflectance or transmittance spectrum acquired by abridged
spectrophotometry. 4.1 The practice assumes that the shape of the passband is
triangular and that the bandwidth is equal to the measurement
1.3 It is applicable where the shape of the passband is
intervalbetweenpassbands.Thisconditionisthoughttobemet
triangular and the bandwidth is equal to the measurement
by a majority of commercial instruments in use in spectropho-
interval between passbands. Information is provided in Section
tometry and spectrocolorimetry. Under those conditions, the
7 for users when that condition is not satisfactorily met.
methods of Section 6 are to be utilized to rectify the raw
1.4 This standard does not purport to address all of the
reflectance or transmittance data for its bandpass differences
safety concerns, if any, associated with its use. It is the
immediately upon the return of the data to the host computer
responsibility of the user of this standard to establish appro-
program from the acquiring instrument, or before presentation
priate safety, health, and environmental practices and deter-
of the data to the user.
mine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accor-
5. Significance and Use
dance with internationally recognized principles on standard-
5.1 Failure to make such a rectification introduces differ-
ization established in the Decision on Principles for the
ences from the true value of the spectrum of about 0.02 to 0.4
Development of International Standards, Guides and Recom-
∆E* units. All users are required to make a rectification of
ab
mendations issued by the World Trade Organization Technical
such bandpass differences. It is especially incumbent upon
Barriers to Trade (TBT) Committee.
writers of computer programs whose function it is to acquire
such spectra from instruments to see that a competent rectifi-
2. Referenced Documents
cation is implemented in the program before any additional
2.1 ASTM Standards:
processing of the spectrum, or calculations involving the
E284 Terminology of Appearance
spectrum are accomplished, or before the spectrum is made
available to a user.
5.2 Legacymeasuringsystemsareexplicitlyexemptedfrom
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
any requirements for retrofitting of hardware or software and
Appearance Analysis.
maycontinuetoutilizepreviouslyacceptedmethodsofmaking
Current edition approved June 1, 2021. Published June 2021. Originally
the bandwidth rectification.
approved in 2009. Last previous edition approved in 2016 as E2729 – 16. DOI:
10.1520/E2729-16R21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 6. Methodology
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
6.1 The First and Last Passbands—In the first and last
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. passband being rectified, no correction is called for. The
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2729 − 16 (2021)
corrected spectral value R should be set equal to the above correction is among the best practices for making a
s,λ
measured spectral value R . rectification of bandpass differences.
m,λ
R 5 R (1) 7.2 While the underlying theory leading to the rectification
s,1 m,1
equations is based on triangular passbands, some related
R 5 R
s,n m,n
bandpass shapes may be adequately rectified by the methods of
this practice. This is true of Gaussian and Lorentzian function
where the subscripts 1 andn refer to the wavelength index of
band shapes, and may be true of instruments with concave
the first and last passbands being corrected.
diffraction gratings imaged on diode arrays with more pixels
6.2 The Second and Next-to-last Passbands—The second
than wavelengths being reported. Those passbands are trap-
and next-to-last passbands being rectified are subject to the
ezoidal in shape.
following correction:
7.3 If the user has specific knowledge as to departures from
R 520.10R 11.21R 2 0.12R 10.01R (2)
s,2 m,1 m,2 m,3 m,4
the above assumptions with respect to his particular measure-
ment conditions, he may calculate a set of correction coeffi-
R 520.10R 11.21R 2 0.12R 10.01R
s,n21 m,n m,n21 m,n22 m,n23
cients fitting his own case from principles laid down in the
where the second subscript refers to the wavelength index of
published literature. Most helpful in this regard will be articles
the bandpass considered.
by Stearns (1,2), Fairman (3), Oleari (4),Venable (5), Gardner
(6), and Ohno (7). Corrections using such coefficients are
6.3 The Remaining Interior Passbands—The remaining in-
deemed to meet the requirements of this practice.
terior passbands are subject to the following five-point rectifi-
cation:
8. Precision and Bias
R 5 0.01R 2 0.12R 11.22R 2 0.12R 10.01R
s,i m,i22 m,i21 m,i m,i11 m,i12
8.1 The rectification has no impact on the precision of any
(3)
test method.
wherethesubscriptiisthewavelengthindexofthepassband
8.2 In the absence of any rectification, the bias introduced
being
...
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