1、Designation: E308 17Standard Practice forComputing the Colors of Objects by Using the CIE System1This standard is issued under the fixed designation E308; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、 number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.INTRODUCTIONStandard tables (Tables 14) of color matching fu
3、nctions and illuminant spectral power distributionshave since 1931 been defined by the CIE, but the CIE has eschewed the role of preparing tables oftristimulus weighting factors for the convenient calculation of tristimulus values. There havesubsequently appeared numerous compilations of tristimulus
4、 weighting factors in the literature withdisparity of data resulting from, for example, different selections of wavelength intervals and methodsof truncating abbreviated wavelength ranges. In 1970, Foster et al. (1)2proposed conventions tostandardize these two features, and Stearns (2) published a m
5、ore complete set of tables. Stearns workand later publications such as the 1985 revision of E308 have greatly reduced the substantial variationsin methods for tristimulus computation that existed several decades ago.The disparities among earlier tables were largely caused by the introduction of comp
6、utations basedon 20-nm wavelength intervals. With the increasing precision of modern instruments, there is alikelihood of a need for tables for narrower wavelength intervals. Stearns tables, based on a 10-nminterval, did not allow the derivation of consistent tables with wavelength intervals less th
7、an 10 nm.The 1-nm table must be designated the basic table if others with greater wavelength intervals are tohave the same white point, and this was the reason for the 1985 revision of E308, resulting in tablesthat are included in the present revision as Tables 5.The 1994 revision was made in order
8、to introduce to the user a method of reducing the dependenceof the computed tristimulus values on the bandpass of the measuring instrument, using methods thatare detailed in this practice.1. Scope1.1 This practice provides the values and practical compu-tation procedures needed to obtain CIE tristim
9、ulus values fromspectral reflectance, transmittance, or radiance data for object-color specimens.1.2 Procedures and tables of standard values are given forcomputing from spectral measurements the CIE tristimulusvalues X, Y, Z, and chromaticity coordinates x, y for the CIE1931 standard observer and X
10、10,Y10,Z10and x10.y10for theCIE 1964 supplementary standard observer.1.3 Standard values are included for the spectral power ofsix CIE standard illuminants and three CIE recommendedfluorescent illuminants.1.4 Procedures are included for cases in which data areavailable only in more limited wavelengt
11、h ranges than thoserecommended, or for a measurement interval wider than thatrecommended by the CIE. This practice is applicable tospectral data obtained in accordance with Practice E1164 with1-, 5-, 10-, or 20-nm measurement interval.1.5 Procedures are included for cases in which the spectraldata a
12、re, and those in which they are not, corrected forbandpass dependence. For the uncorrected cases, it is assumedthat the spectral bandpass of the instrument used to obtain thedata was approximately equal to the measurement interval and1This practice is under the jurisdiction of ASTM Committee E12 on
13、Color andAppearance and is the direct responsibility of Subcommittee E12.04 on Color andAppearance Analysis.Current edition approved May 1, 2017. Published August 2017. Originallyapproved in 1966. Last previous edition approved in 2015 as E308 15. DOI:10.1520/E0308-17.2The boldface numbers in parent
14、heses refer to the list of references at the end ofthis practice.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization esta
15、blished in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1was triangular in shape. These choices are believed to corre-spond to the most widely used industrial pr
16、actice.1.6 This practice includes procedures for conversion ofresults to color spaces that are part of the CIE system, such asCIELAB and CIELUV (3). Equations for calculating colordifferences in these and other systems are given in PracticeD2244.1.7 The values stated in SI units are to be regarded a
17、sstandard. No other units of measurement are included in thisstandard.1.8 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health and environmental practices an
18、d deter-mine the applicability of regulatory limitations prior to use.1.9 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-
19、mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:3D2244 Practice for Calculation of Color Tolerances andColor Differences from Instrumentally Measured ColorCoordinatesE284 Terminology of AppearanceE313 Practice for
20、 Calculating Yellowness and WhitenessIndices from Instrumentally Measured Color CoordinatesE1164 Practice for Obtaining Spectrometric Data for Object-Color EvaluationE2022 Practice for Calculation of Weighting Factors forTristimulus IntegrationE2729 Practice for Rectification of SpectrophotometricBa
21、ndpass Differences2.2 ANSI Standard:PH2.23 Lighting Conditions for Viewing PhotographicColor Prints and Transparencies42.3 CIE/ISO Standards:ISO Standard 11664-1:2007(E)/CIE S 013-1/E:2006 Stan-dard Colorimetric Observers4,5ISO Standard 11664-2:2007(E)/CIE S 014-2/E:2006 Colori-metric Illuminants4,5
22、CIE Standard D 001 Colorimetric Illuminants and Observers(Disk)52.4 ASTM Adjuncts:Computer disk containing Tables 5 and 663. Terminology3.1 Definitions of terms in Terminology E284 are applicableto this practice (see also Ref (4).3.2 Definitions:3.2.1 bandpass, adjhaving to do with a passband.3.2.2
23、bandwidth, nthe width of a passband at its half-peaktransmittance.3.2.3 chromaticity, nthe color quality of a color stimulusdefinable by its chromaticity coordinates.3.2.4 chromaticity coordinates, nthe ratio of each of thetristimulus values of a psychophysical color (see section3.2.7.11) to the sum
24、 of the tristimulus values.3.2.4.1 DiscussionIn the CIE 1931 standard colorimetricsystem, the chromaticity coordinates are: x = X/(X+Y+Z),y=Y/(X+Y+Z), z=Z/(X+Y+Z); in the CIE 1964 supple-mentary colorimetric system, the same equations apply with allsymbols having the subscript 10 (see 3.2.7).3.2.5 C
25、IE, nthe abbreviation for the French title of theInternational Commission on Illumination, Commission Inter-nationale de lclairage.3.2.6 CIE 1931 (x, y) chromaticity diagram,nchromaticity diagram for the CIE 1931 standard observer,in which the CIE 1931 chromaticity coordinates are plotted,with x as
26、abscissa and y as ordinate.3.2.7 CIE 1964 (x10,y10) chromaticity diagram,nchromaticity diagram for the CIE 1964 supplementarystandard observer, in which the CIE 1964 chromaticity coor-dinates are plotted, with x10as abscissa and y10as ordinate.3.2.7.1 DiscussionFig. 1 shows the CIE 1931 and 1964chro
27、maticity diagrams, including the locations of the spectrumlocus and the connecting purple boundary.3.2.8 CIE 1976 (u, v) or (u10,v10) chromaticity diagram,nchromaticity diagram in which the CIE 1976 L* u* v*(CIELUV) chromaticity coordinates are plotted, with u (oru10) as abscissa and v (or v10) as o
28、rdinate.3.2.9 CIE 1931 standard colorimetric system, na systemfor determining the tristimulus values of any spectral powerdistribution using the set of reference color stimuli, X, Y, Z andthe three CIE colormatching functions x(), y(), z() adoptedby the CIE in 1931.3.2.10 CIE 1964 supplementary stan
29、dard colorimetricsystem, na system for determining the tristimulus values ofany spectral power distribution using the set of reference colorstimuli X10, Y10, Z10and the three CIE color-matching func-tions x10(), y10(), z10() adopted by the CIE in 1964 (see Note1).NOTE 1Users should be aware that the
30、 CIE 1964 (10) supplementarysystem and standard observer assume no contribution or constant contri-bution of rods to vision. Under some circumstances, such as in viewinghighly metameric pairs in very low light levels (where the rods areunsaturated), the amount of rod participation can vary between t
31、hemembers of the pair. This is not accounted for by any trichromatic systemof colorimetry. The 10 system and observer should be used with cautionin such circumstances.3.2.11 color, nof an object, aspect of object appearancedistinct from form, shape, size, position or gloss that depends3For reference
32、d ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Available from American National Standards Institute (ANSI), 25 W. 43rd St
33、.,4th Floor, New York, NY 10036, http:/www.ansi.org.5Available from CIE (International Commission on Illumination), http:/www.cie.co.at or http:/.6Computer disk of 72 tables is available from ASTM Headquarters. RequestAdjunct No. ADJE0308A. Originally approved in 1994.E308 172upon the spectral compo
34、sition of the incident light, the spectralreflectance, transmittance, or radiance of the object, and thespectral response of the observer, as well as the illuminatingand viewing geometry.3.2.12 color, npsychophysical, characteristics of a colorstimulus (that is, light producing a visual sensation of
35、 color)denoted by a colorimetric specification with three values, suchas tristimulus values.3.2.13 colormatching functions, nthe amounts, in anytrichromatic system, of three reference color stimuli needed tomatch, by additive mixing, monochromatic components of anequalenergy spectrum.3.2.14 fluoresc
36、ent illuminant, nilluminant representingthe spectral distribution of the radiation from a specified typeof fluorescent lamp.3.2.15 CIE recommended fluorescent illuminants, na setof spectral power distributions of 12 types of fluorescentlamps, the most important of which are FL2, representing acool w
37、hite fluorescent lamp with correlated color temperature4200 K, FL7, a broad-band (continuous-spectrum) daylightlamp (6500 K), and FL11, a narrow-band (line-spectrum) whitefluorescent lamp (4000 K).3.2.16 luminous, adjweighted according to the spectralluminous efficiency function V() of the CIE.3.2.1
38、7 opponent-color scales, nscales that denote onecolor by positive scale values, the neutral axis by zero value,and an approximately complementary color by negative scalevalues, common examples being scales that are positive in thered direction and negative in the green direction, and those thatare p
39、ositive in the yellow direction and negative in the bluedirection.3.2.18 CIELAB color scales, nCIE 1976 L*, a*, b*opponent-color scales, in which a* is positive in the reddirection and negative in the green direction, and b* is positivein the yellow direction and negative in the blue direction.3.2.1
40、9 CIELUV color scales, nCIE 1976 L*, u*, v*opponent-color scales, in which u* is positive in the reddirection and negative in the green direction, and v* is positivein the yellow direction and negative in the blue direction.3.2.20 passband, na contiguous band of wavelengths inwhich at least a fracti
41、on of the incident light is selectivelytransmitted by a light-modulating device or medium.3.2.21 spectral, adjfor radiometric quantities, pertainingto monochromatic radiation at a specified wavelength or, byextension, to radiation within a narrow wavelength band abouta specified wavelength.3.2.22 st
42、andard illuminant, na luminous flux, specified byits spectral distribution, meeting specifications adopted by astandardizing organization.3.2.23 CIE standard illuminant A, ncolorimetricilluminant, representing the full radiator at 2855.6 K, definedby the CIE in terms of a relative spectral power dis
43、tribution.3.2.24 CIE standard illuminant C, ncolorimetricilluminant, representing daylight with a correlated color tem-perature of 6774 K, defined by the CIE in terms of a relativespectral power distribution.FIG. 1 The CIE 1931 x, y and 1964 x10,y10Chromaticity Diagrams Ref (5) (see Note 2)E308 1733
44、.2.25 CIE standard illuminant D65,ncolorimetricilluminant, representing daylight with a correlated color tem-perature of 6504 K, defined by the CIE in terms of a relativespectral power distribution.3.2.25.1 DiscussionOther illuminants of importance de-fined by the CIE include the daylight illuminant
45、s D50, D55, andD75. Illuminant D50is used by the graphic arts industry forviewing colored transparencies and prints (see ANSI PH2.23).3.2.26 standard observer, nan ideal observer having vi-sual response described by the CIE color-matching functions(see CIE S 013 and Ref (3).3.2.27 CIE 1931 standard
46、observer, nideal colorimetricobserver with color-matching functions x(), y(), z() corre-sponding to a field of view subtending a 2 angle on the retina;commonly called the “2 standard observer.”3.2.28 CIE 1964 supplementary standard observer, nidealcolorimetric observer with color-matching functions
47、x10(),y10(), z10() corresponding to a field of view subtending a 10angle on the retina; commonly called the “10 standardobserver” (see Note 1).3.2.29 tristimulus values, nsee 3.2.9 and 3.2.10.3.2.30 tristimulus weighting factors, Sx, Sy, Sz, nfactorsobtained from products of the spectral power S of
48、an illuminantand the spectral color-matching functions x, y, z (or x10, y10,z10) of an observer, usually tabulated at wavelength intervals of10 or 20 nm, used to compute tristimulus values by multipli-cation by the spectral reflectance, transmittance, or radiance (orthe corresponding factors) and su
49、mmation.3.2.30.1 DiscussionProper account should be taken of thespectral bandpass of the measuring instrument.4. Summary of Practice4.1 Selection of ParametersThe user of this practice mustselect values of the following parameters:4.1.1 ObserverSelect either the CIE 1931 standard colo-rimetric observer (2 observer) or the CIE 1964 supplementarystandard observer (10 observer), tabulated in this practice,CIE Standard S 013 or D 001, or Ref (3) (see 3.2.26 and Note1).
