1、Designation: E 308 06Standard 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 (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.INTRODUCTIONStandard tables (Tables 1-4) of color matching fun
3、ctions 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 mo
5、re 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 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 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 Ta
9、bles 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 tha
10、t 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 forcomputin
11、g 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 thr
12、ee 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 accord
13、ance 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 t
14、o 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, 2006. Published Janua
15、ry 2007. Originallyapproved in 1966. Last previous edition approved in 2001 as E 308 01.2The 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.w
16、as 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 th
17、ese and other systems are given in PracticeD 2244.1.7 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 and health practices and determine the applica-bility of r
18、egulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D 2244 Practice for Calculation of Color Tolerances andColor Differences from Instrumentally Measured ColorCoordinatesE 284 Terminology of AppearanceE 313 Practice for Calculating Yellowness and WhitenessIndices from Instr
19、umentally Measured Color CoordinatesE 1164 Practice for Obtaining Spectrometric Data forObject-Color Evaluation2.2 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-nants4,45CIE
20、Standard S 002/ISO IS 10527, Colorimetric Observ-ers4,45CIE Standard D 001, Colorimetric Illuminants 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 Defi
21、nitions:3.2.1 bandwidth, nthe width of a passband at its half-peaktransmittance.3.2.2 chromaticity, nthe color quality of a color stimulusdefinable by its chromaticity coordinates.3.2.3 chromaticity coordinates, nthe ratio of each of thetristimulus values of a psychophysical color (see section3.2.7.
22、11) to the sum of the tristimulus values.3.2.3.1 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
23、 3.2.6.).3.2.4 CIE, nthe abbreviation for the French title of theInternational Commission on Illumination, Commission Inter-nationale de lclairage.3.2.5 CIE 1931 (x, y) chromaticity diagram,nchromaticity diagram for the CIE 1931 standard observer,in which the CIE 1931 chromaticity coordinates are pl
24、otted,with x as abscissa and y as ordinate.3.2.6 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.3.2.6.1 DiscussionFig. 1 shows the CIE 1
25、931 and 1964chromaticity diagrams, including the locations of the spectrumlocus and the connecting purple boundary.3.2.7 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
26、and v8 (or v810) as ordinate.3.2.8 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 (l), y (l), z (l)adopted by the CIE in 1931.3.2.9 C
27、IE 1964 supplementary standard colorimetric sys-tem, na 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
28、1Users should be aware that the 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 p
29、articipation can vary between themembers 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.3.2.10 color, nof an object, aspect of object appearancedistinct from form, shape, size, position or g
30、loss that dependsupon the spectral composition 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.3.2.11 color, npsychophysical, characteristics of a colorstimulus (that i
31、s, light producing a visual sensation of color)denoted by a colorimetric specification with three values, suchas tristimulus values.3.2.12 colormatching functions, n the amounts, in anytrichromatic system, of three reference color stimuli needed tomatch, by additive mixing, monochromatic components
32、of anequalenergy spectrum.3.2.13 fluorescent illuminant, nilluminant representingthe spectral distribution of the radiation from a specified typeof fluorescent lamp.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Bo
33、ok 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 of the CIE (International Com
34、missionon 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.E3080623.2.14 CIE recommended fluorescent illuminants, na setof spectral pow
35、er distributions of 12 types of fluorescentlamps, the most 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)
36、.3.2.15 luminous, adjweighted according to the spectralluminous efficiency function V (l) of the CIE.3.2.16 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 b
37、eing scales that are positive in thered direction and negative in the green direction, and those thatare positive in the yellow direction and negative in the bluedirection.3.2.17 CIELAB color scales, nCIE 1976 L*, a*, b*opponent-color scales, in which a* is positive in the reddirection and negative
38、in the green direction, and b* is positivein the yellow direction and negative in the blue direction.3.2.18 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 n
39、egative in the blue direction.3.2.19 passband, na narrow portion of a dispersed spec-trum, selected by the exit slit of a monochromator or theequivalent, for the purpose of defining an emitted spectralpower function.3.2.19.1 DiscussionThe shape of the spectral transmit-tance function of the passband
40、 may be triangular, trapezoidal,or rectangular, among others, but is usually symmetrical.3.2.20 spectral, adjfor radiometric quantities, pertainingto monochromatic radiation at a specified wavelength or, byextension, to radiation within a narrow wavelength band abouta specified wavelength.3.2.21 sta
41、ndard illuminant, na luminous flux, specified byits spectral distribution, meeting specifications adopted by astandardizing organization.3.2.22 CIE standard illuminant A, ncolorimetric illumi-nant, representing the full radiator at 2855.6 K, defined by theCIE in terms of a relative spectral power di
42、stribution.3.2.23 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.3.2.24 CIE standard illuminant D65, ncolorimetric illumi-nant, representing daylight with a
43、 correlated color temperatureof 6504 K, defined by the CIE in terms of a relative spectralpower distribution.3.2.24.1 DiscussionOther illuminants of importance de-fined by the CIE include the daylight illuminants D50, D55, andD75. Illuminant D50is used by the graphic arts industry forviewing colored
44、 transparencies and prints (see ANSI PH2.23).3.2.25 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 Diagrams Ref (5) (see Note 2)E3080633.2.26 CIE 1931 standar
45、d 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.”3.2.27 CIE 1964 supplementary standard observer,nideal colorimetric observer with color-matching func
46、tionsx10(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).3.2.28 tristimulus values, nsee 3.2.8 and 3.2.9.3.2.29 tristimulus weighting factors, Sx, Sy, Sz , nfactorsobtained from products of the spectral
47、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, transmittance, or radiance (orthe corresponding fact
48、ors) and summation.3.2.29.1 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-rim
49、etric observer (2 observer) or the CIE 1964 supplementarystandard observer (10 observer), tabulated in this practice,CIE Standard S 002 or D 001,orRef(3) (see 3.2.25 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,orRef(3) (see 3.2.21).4.1.3 Measurement IntervalSelect the measurement inter-val of the available spectral data. This practice provides for 1-,5-, 10-, or 20-nm measurement intervals. For best practice th
