1、Designation: E 308 08Standard Practice forComputing the Colors of Objects by Using the CIE System1This standard is issued under the fixed designation E 308; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、 A 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 Department of Defense.INTRODUCTIONStandard tables (Tables 1-4) of color matching func
3、tions 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 w
4、eighting 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 mor
5、e complete set of tables. Stearns workand later publications such as the 1985 revision of E 308 have greatly reduced the substantialvariations in methods for tristimulus computation that existed several decades ago.The disparities among earlier tables were largely caused by the introduction of compu
6、tations 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 tha
7、n 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 E 308, 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. These changes, however, lead to tables (Tables 6 in this practice) that aresubstantially different from the Tab
9、les 5 that have been in use since 1985. There is accordingly adanger, if the new tables are introduced but not universally adopted, that there may again be, perhapsfor several decades, a significant disparity among the tables of tristimulus weighting factors commonlyused. It is highly desirable that
10、 this should be avoided.1. Scope1.1 This practice provides the values and practical compu-tation procedures needed to obtain CIE tristimulus values fromspectral reflectance, transmittance, or radiance data for object-color specimens.1.2 Procedures and tables of standard values are given forcomputing
11、 from spectral measurements the CIE tristimulusvalues X, Y, Z, and chromaticity coordinates x, y for the CIE1931 standard observer and X10,Y10,Z10and x10.y10for theCIE 1964 supplementary standard observer.1.3 Standard values are included for the spectral power ofsix CIE standard illuminants and thre
12、e CIE recommendedfluorescent illuminants.1.4 Procedures are included for cases in which data areavailable only in more limited wavelength ranges than thoserecommended, or for a measurement interval wider than thatrecommended by the CIE. This practice is applicable tospectral data obtained in accorda
13、nce with Practice E 1164 with1-, 5-, 10-, or 20-nm measurement interval.1.5 Procedures are included for cases in which the spectraldata are, 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
14、 obtain thedata was approximately equal to the measurement interval and1This practice is under the jurisdiction of ASTM Committee E12 on Color andAppearance and is the direct responsibility of Subcommittee E12.04 on Color andAppearance Analysis.Current edition approved Dec. 1, 2008. Published Januar
15、y 2009. Originallyapproved in 1966. Last previous edition approved in 2006 as E 308 06.2The boldface numbers in parentheses refer to the list of references at the end ofthis practice.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.wa
16、s triangular in shape. These choices are believed to corre-spond to the most widely used industrial practice.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 the
17、se and other systems are given in PracticeD 2244.1.7 The values stated in SI units are to be regarded asstandard. 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 theresponsibili
18、ty of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D 2244 Practice for Calculation of Color Tolerances andColor Differences from Instrumentally Measur
19、ed ColorCoordinatesE 284 Terminology of AppearanceE 313 Practice for Calculating Yellowness and WhitenessIndices from Instrumentally Measured Color CoordinatesE 1164 Practice for Obtaining Spectrometric Data forObject-Color EvaluationE 2022 Practice for Calculation of Weighting Factors forTristimulu
20、s Integration2.2 ANSI Standard:PH2.23 Lighting Conditions for Viewing PhotographicColor Prints and Transparencies42.3 CIE/ISO Standards:CIE Standard S 001/ISO IS 10526, Colorimetric Illumi-nants4,5CIE Standard S 002/ISO IS 10527, Colorimetric Observ-ers4,5CIE Standard D 001, Colorimetric Illuminants
21、 and Observ-ers (Disk)52.4 ASTM Adjuncts:Computer disk containing Tables 5 and 663. Terminology3.1 Definitions of terms in Terminology E 284 are appli-cable to this practice (see also Ref (4).3.2 Definitions:3.2.1 bandpass, adjhaving to with a passband.3.2.2 bandwidth, nthe width of a passband at it
22、s 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 of the tristimulus values.3.2.4.1 Discus
23、sionIn 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 CIE, nthe abbreviation for the French ti
24、tle 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 abscissa and y as ordinate.3.2.7 CIE 19
25、64 (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 1964chromaticity diagrams, including the locati
26、ons of the spectrumlocus and the connecting purple boundary.3.2.8 CIE 1976 (u8,v8)or(u810,v810) chromaticity diagram,nchromaticity diagram in which the CIE 1976 L* u* v*(CIELUV) chromaticity coordinates are plotted, with u8 (oru810) as abscissa and v8 (or v810) as ordinate.3.2.9 CIE 1931 standard co
27、lorimetric 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 (l), y (l), z (l)adopted by the CIE in 1931.3.2.10 CIE 1964 supplementary standard colorimetric sys-tem, n
28、a system for determining the tristimulus values of anyspectral power distribution using the set of reference colorstimuli X10, Y10, Z10and the three CIE color-matching func-tions x10(l), y10(l), z10(l) adopted by the CIE in 1964 (seeNote 1).NOTE 1Users should be aware that the CIE 1964 (10) suppleme
29、ntarysystem 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 themembers of the pair.
30、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 dependsupon the spectral composition of the
31、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 color)denoted
32、 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 to3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at se
33、rviceastm.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.,4th Floor, New York, NY 10036, http:/www.ansi.org.5Available from U.S. National Committee o
34、f the CIE (International Commissionon Illumination), C/o Thomas M. Lemons, TLA-Lighting Consultants, Inc., 7 PondSt., Salem, MA 01970, http:/www.cie-usnc.org.6Computer disk of 72 tables is available from ASTM Headquarters. RequestAdjunct No. ADJE0308a.E308082match, by additive mixing, monochromatic
35、components of anequalenergy spectrum.3.2.14 fluorescent 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 m
36、ost important of which are F2, representing a coolwhite fluorescent lamp with correlated color temperature 4200K, F7, a broad-band (continuous-spectrum) daylight lamp(6500 K), and F11, a narrow-band (line-spectrum) whitefluorescent lamp (4000 K).3.2.16 luminous, adjweighted according to the spectral
37、luminous efficiency function V (l) of the CIE.3.2.17 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 n
38、egative in the green direction, and those thatare positive 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
39、 direction and negative in the blue direction.3.2.19 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 conti
40、guous band of wavelengths inwhich at least a fraction 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 wa
41、velength band abouta specified wavelength.3.2.22 standard illuminant, na luminous flux, specified byits spectral distribution, meeting specifications adopted by astandardizing organization.3.2.23 CIE standard illuminant A, ncolorimetric illumi-nant, representing the full radiator at 2855.6 K, define
42、d by theCIE in terms of a relative spectral power distribution.3.2.24 CIE standard illuminant C, ncolorimetric illumi-nant, representing daylight with a correlated color temperatureof 6774 K, defined by the CIE in terms of a relative spectralpower distribution.3.2.25 CIE standard illuminant D65, nco
43、lorimetric illumi-nant, representing daylight with a correlated color temperatureof 6504 K, defined by the CIE in terms of a relative spectralpower distribution.3.2.25.1 DiscussionOther illuminants of importance de-fined by the CIE include the daylight illuminants D50, D55, andD75. Illuminant D50is
44、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 S002 and Ref (3).FIG. 1 The CIE 1931 x , y and 1964 x10, y10Chromaticity Diagram
45、s Ref (5) (see Note 2)E3080833.2.27 CIE 1931 standard observer, nideal colorimetricobserver with color-matching functions x (l), y (l), z (l)corresponding to a field of view subtending a 2 angle on theretina; commonly called the “2 standard observer.”3.2.28 CIE 1964 supplementary standard observer,n
46、ideal colorimetric observer with color-matching functionsx10(l), y10(l), z10(l) corresponding to a field of view subtend-ing a 10 angle on the retina; commonly called the “10standard observer” (see Note 1).3.2.29 tristimulus values, nsee 3.2.9 and 3.2.10.3.2.30 tristimulus weighting factors, Sx, Sy,
47、 Sz , nfactorsobtained from products of the spectral power S of 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,
48、 transmittance, or radiance (orthe corresponding factors) and summation.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
49、 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 002 or D 001, or Ref (3) (see 3.2.26 and Note1).4.1.2 IlluminantSelect one of the CIE standard or recom-mended illuminants tabulated in this practice, CIE StandardS 001 or D 001, or Ref (3) (see 3.2.22).4.1.3 Measurement IntervalSelect the measurement inter-val of the available spectral data. This practice provides for 1-,5
