Standard Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates

SCOPE
1.1 This practice covers the calculation, from instrumentally measured color coordinates based on daylight illumination, of color tolerances and small color differences between opaque specimens such as painted panels, plastic plaques, or textile swatches. Where it is suspected that the specimens may be metameric, that is, possess different spectral curves though visually alike in color, Practice D 4086 should be used to verify instrumental results. The tolerances and differences determined by these procedures are expressed in terms of approximately uniform visual color perception in CIE 1976 CIELAB opponent-color space  (1), CMC tolerance units (2), CIE94 tolerance units  (3), the DIN99 color difference formula given in DIN 6176 (4), or the new CIEDE2000 color difference units (5). The color differences based on Hunter LH, aH, bH opponent-color space (6), or the Friele-MacAdam-Chickering (FMC-2) color space (7), are no longer recommended for industrial practice.
1.2 For product specification, the purchaser and the seller shall agree upon the permissible color tolerance between test specimen and reference and the procedure for calculating the color tolerance. Each material and condition of use may require specific color tolerances because other appearance factors, (for example, specimen proximity, gloss, and texture), may affect the correlation between the magnitude of a measured color difference and its commercial acceptability.
1.3 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 requirements prior to use.

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Status
Historical
Publication Date
09-Jun-2002
Current Stage
Ref Project

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ASTM D2244-02e1 - Standard Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates
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e1
Designation:D2244–02
Standard Practice for
Calculation of Color Tolerances and Color Differences from
1
Instrumentally Measured Color Coordinates
This standard is issued under the fixed designation D2244; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber 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.
1
e NOTE—Equation 38 was editorially corrected in July 2003.
INTRODUCTION
This practice originally resulted from the consolidation of a number of separately published
methodsfortheinstrumentalevaluationofcolordifferences.Asrevisedin1979,itincludedfourcolor
spaces in which color-scale values could be measured by instruments, many of which were obsolete,
and the color differences calculated by ten equations for different color scales. The sections on
apparatus,calibrationstandardsandmethods,andmeasurementproceduresservedlittlepurposeinthe
lightofmoderncolor-measurementtechnology.Therevisionpublishedin1993omittedthesesections,
and limited the color spaces and color-difference equations considered, to the three most widely used
in the paint and related coatings industry. This revision adds two new color tolerance equations and
putstwoofthecolordifferenceequationsfromthe1993versioninaninformativeannexforhistorical
purposes. The Hunter L , a , b and FMC-2 color difference equations are no longer recommended.
H H H
This revision also changes the status of the standard from test method to practice.
1. Scope 1.2 For product specification, the purchaser and the seller
shall agree upon the permissible color tolerance between test
1.1 Thispracticecoversthecalculation,frominstrumentally
specimen and reference and the procedure for calculating the
measured color coordinates based on daylight illumination, of
colortolerance.Eachmaterialandconditionofusemayrequire
color tolerances and small color differences between opaque
specific color tolerances because other appearance factors, (for
specimens such as painted panels, plastic plaques, or textile
example, specimen proximity, gloss, and texture), may affect
swatches. Where it is suspected that the specimens may be
the correlation between the magnitude of a measured color
metameric, that is, possess different spectral curves though
difference and its commercial acceptability.
visuallyalikeincolor,PracticeD4086shouldbeusedtoverify
1.3 This standard does not purport to address all of the
instrumentalresults.Thetolerancesanddifferencesdetermined
safety concerns, if any, associated with its use. It is the
by these procedures are expressed in terms of approximately
responsibility of the user of this standard to establish appro-
uniform visual color perception in CIE 1976 CIELAB
2
priate safety and health practices and determine the applica-
opponent-color space (1) , CMC tolerance units (2), CIE94
bility of regulatory requirements prior to use.
tolerance units (3), the DIN99 color difference formula given
in DIN 6176 (4), or the new CIEDE2000 color difference units
2. Referenced Documents
(5). The color differences based on Hunter L , a , b
H H H
2.1 ASTM Standards:
opponent-color space (6), or the Friele-MacAdam-Chickering
D1729 Practice for Visual Appraisal of Colors and Color
(FMC-2) color space (7), are no longer recommended for
3
Differences of Diffusely-Illuminated Opaque Materials
industrial practice.
3
D4086 Practice for Visual Evaluation of Metamerism
3
E284 Terminology of Appearance
1
This practice is under the jurisdiction of ASTM Committee E12 on Color and E308 Practice for Computing the Colors of Objects by
3
Appearance and is the direct responsibility of Subcommittee E12.04 on Color and
Using the CIE System
Appearance Analysis.
E805 PracticeforIdentificationofInstrumentalMethodsof
Current edition approved June 10, 2002. Published August 2002. Originally
published as D2244–64T. Last previous edition D2244–93 (2000).
2
The boldface numbers in parentheses refer to the list of references at the end of
3
this standard. Annual Book of ASTM Standards, Vol 06.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D2244–02
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Color or Color-Difference Measurement of Materials automatically make the computations. Color-difference units
E1164 Practice for Obtaining Spectrophotometric Data for are computed, from these color-scale values, and approximate
3
Object-Color Evaluation the perceived color differences between the reference and the
2.2 Other Standards: test specimen.
DIN 6176 Farbmetrische, Bestimmung von Far
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