1、Designation: E308 13E308 15Standard 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 revi
2、sion. 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 U.S. Department of Defense.INTRODUCTIONStandard tables (Tables 14) of color matc
3、hing functions 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 tris
4、timulus 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)2 proposed conventions tostandardize these two features, and Stearns (2) publi
5、shed a more 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
6、 of computations 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
7、 less than 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 i
8、n order 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 computation procedures needed to obtain CIE
9、tristimulus values fromspectral reflectance, transmittance, or radiance data for object-color specimens.1.2 Procedures and tables of standard values are given for computing from spectral measurements the CIE tristimulus valuesX, Y, Z, and chromaticity coordinates x, y for the CIE 1931 standard obser
10、ver and X10, Y10, Z10 and x10. y10 for the CIE 1964supplementary standard observer.1.3 Standard values are included for the spectral power of six CIE standard illuminants and three CIE recommended fluorescentilluminants.1.4 Procedures are included for cases in which data are available only in more l
11、imited wavelength ranges than thoserecommended, or for a measurement interval wider than that recommended by the CIE. This practice is applicable to spectral dataobtained in accordance with Practice E1164 with 1-, 5-, 10-, or 20-nm measurement interval.1.5 Procedures are included for cases in which
12、the spectral data are, and those in which they are not, corrected for bandpassdependence. For the uncorrected cases, it is assumed that the spectral bandpass of the instrument used to obtain the data wasapproximately equal to the measurement interval and was triangular in shape. These choices are be
13、lieved to correspond to the mostwidely used industrial practice.1 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 andAppearance Analysis.Current edition approved Oct. 1, 2013April 1, 2015. Publishe
14、d November 2013May 2015. Originally approved in 1966. Last previous edition approved in 20122013 asE308 12.E308 13. DOI: 10.1520/E0308-13.10.1520/E0308-15.2 The boldface numbers in parentheses refer to the list of references at the end of this practice.This document is not an ASTM standard and is in
15、tended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the cur
16、rent versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States11.6 This practice includes procedures for conversion of results to color spaces that are part o
17、f the CIE system, such as CIELABand CIELUV (3). Equations for calculating color differences in these and other systems are given in Practice D2244.1.7 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.8 This standard does not
18、purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D
19、2244 Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color CoordinatesE284 Terminology of AppearanceE313 Practice for Calculating Yellowness and Whiteness Indices from Instrumentally Measured Color CoordinatesE1164 Practice for Obtaining Spectrometric
20、Data for Object-Color EvaluationE2022 Practice for Calculation of Weighting Factors for Tristimulus IntegrationE2729 Practice for Rectification of Spectrophotometric Bandpass Differences2.2 ANSI Standard:PH2.23 Lighting Conditions for Viewing Photographic Color Prints and Transparencies42.3 CIE/ISO
21、Standards:ISO Standard 11664-1:2007(E)/CIE S 013-1/E:2006 Standard Colorimetric Observers4,5ISO Standard 11664-2:2007(E)/CIE S 014-2/E:2006 Colorimetric Illuminants4,5CIE Standard D 001 Colorimetric Illuminants and Observers (Disk)52.4 ASTM Adjuncts:Computer disk containing Tables 5 and 663. Termino
22、logy3.1 Definitions of terms in Terminology E284 are applicable to this practice (see also Ref (4).3.2 Definitions:3.2.1 bandpass, adjhaving to do with a passband.3.2.2 bandwidth, nthe width of a passband at its half-peak transmittance.3.2.3 chromaticity, nthe color quality of a color stimulus defin
23、able by its chromaticity coordinates.3.2.4 chromaticity coordinates, nthe ratio of each of the tristimulus values of a psychophysical color (see section 3.2.7.11)to the sum of the tristimulus values.3.2.4.1 DiscussionIn the CIE 1931 standard colorimetric system, the chromaticity coordinates are: x =
24、 X/(X + Y + Z), y = Y/(X + Y + Z), z = Z/(X + Y + Z); in the CIE 1964 supplementary colorimetric system, the same equations apply with all symbols having the subscript10 (see 3.2.7).3.2.5 CIE, nthe abbreviation for the French title of the International Commission on Illumination, Commission Internat
25、ionalede lclairage.3.2.6 CIE 1931 (x, y) chromaticity diagram, nchromaticity diagram for the CIE 1931 standard observer, in which the CIE1931 chromaticity coordinates are plotted, with x as abscissa and y as ordinate.3.2.7 CIE 1964 (x10, y10) chromaticity diagram, nchromaticity diagram for the CIE 1
26、964 supplementary standard observer,in which the CIE 1964 chromaticity coordinates are plotted, with x10 as abscissa and y10 as ordinate.3.2.7.1 DiscussionFig. 1 shows the CIE 1931 and 1964 chromaticity diagrams, including the locations of the spectrum locus and the connectingpurple boundary.3 For r
27、eferencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.4 Available from American National Standards Institute (ANSI), 25 W.
28、 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.5 Available from CIE (International Commission on Illumination), http:/www.cie.co.at6 Computer disk of 72 tables is available from ASTM Headquarters. Request Adjunct No. ADJE0308A. Originally approved in 1994.E308 1523.2.8 CIE 1976 (u, v)
29、or (u10, v10) chromaticity diagram, nchromaticity diagram in which the CIE 1976 L* u* v* (CIELUV)chromaticity coordinates are plotted, with u (or u10) as abscissa and v (or v10) as ordinate.3.2.9 CIE 1931 standard colorimetric system, na system for determining the tristimulus values of any spectral
30、powerdistribution using the set of reference color stimuli, X, Y, Z and the three CIE colormatching functions x(), y(), z() adoptedby the CIE in 1931.3.2.10 CIE 1964 supplementary standard colorimetric system, na system for determining the tristimulus values of any spectralpower distribution using t
31、he set of reference color stimuli X10, Y10, Z10 and the three CIE color-matching functions x10(), y10(),z10() adopted by the CIE in 1964 (see Note 1).NOTE 1Users should be aware that the CIE 1964 (10) supplementary system and standard observer assume no contribution or constant contributionof rods t
32、o vision. Under some circumstances, such as in viewing highly metameric pairs in very low light levels (where the rods are unsaturated), theamount of rod participation can vary between the members of the pair.This is not accounted for by any trichromatic system of colorimetry.The 10 systemand observ
33、er should be used with caution in such circumstances.3.2.11 color, nof an object, aspect of object appearance distinct from form, shape, size, position or gloss that depends uponthe spectral composition of the incident light, the spectral reflectance, transmittance, or radiance of the object, and th
34、e spectralresponse of the observer, as well as the illuminating and viewing geometry.3.2.12 color, npsychophysical, characteristics of a color stimulus (that is, light producing a visual sensation of color) denotedby a colorimetric specification with three values, such as tristimulus values.3.2.13 c
35、olormatching functions, nthe amounts, in any trichromatic system, of three reference color stimuli needed to match,by additive mixing, monochromatic components of an equalenergy spectrum.3.2.14 fluorescent illuminant, nilluminant representing the spectral distribution of the radiation from a specifi
36、ed type offluorescent lamp.3.2.15 CIE recommended fluorescent illuminants, na set of spectral power distributions of 12 types of fluorescent lamps, themost important of which are FL2, representing a cool white fluorescent lamp with correlated color temperature 4200 K, FL7, abroad-band (continuous-sp
37、ectrum) daylight lamp (6500 K), and FL11, a narrow-band (line-spectrum) white fluorescent lamp (4000K).3.2.16 luminous, adjweighted according to the spectral luminous efficiency function V() of the CIE.FIG. 1 The CIE 1931 x,yand 1964x10,y10 Chromaticity Diagrams Ref (5) (see Note 2)E308 1533.2.17 op
38、ponent-color scales, nscales that denote one color by positive scale values, the neutral axis by zero value, and anapproximately complementary color by negative scale values, common examples being scales that are positive in the red directionand negative in the green direction, and those that are po
39、sitive in the yellow direction and negative in the blue direction.3.2.18 CIELAB color scales, nCIE 1976 L*, a*, b* opponent-color scales, in which a* is positive in the red direction andnegative in the green direction, and b* is positive in the yellow direction and negative in the blue direction.3.2
40、.19 CIELUV color scales, nCIE 1976 L*, u*, v* opponent-color scales, in which u* is positive in the red direction andnegative in the green direction, and v* is positive in the yellow direction and negative in the blue direction.3.2.20 passband, na contiguous band of wavelengths in which at least a f
41、raction of the incident light is selectively transmittedby a light-modulating device or medium.3.2.21 spectral, adjfor radiometric quantities, pertaining to monochromatic radiation at a specified wavelength or, byextension, to radiation within a narrow wavelength band about a specified wavelength.3.
42、2.22 standard illuminant, na luminous flux, specified by its spectral distribution, meeting specifications adopted by astandardizing organization.3.2.23 CIE standard illuminant A, ncolorimetric illuminant, representing the full radiator at 2855.6 K, defined by the CIE interms of a relative spectral
43、power distribution.3.2.24 CIE standard illuminant C, ncolorimetric illuminant, representing daylight with a correlated color temperature of 6774K, defined by the CIE in terms of a relative spectral power distribution.3.2.25 CIE standard illuminant D65, ncolorimetric illuminant, representing daylight
44、 with a correlated color temperature of6504 K, defined by the CIE in terms of a relative spectral power distribution.3.2.25.1 DiscussionOther illuminants of importance defined by the CIE include the daylight illuminants D50, D55, and D75. Illuminant D50 is used bythe graphic arts industry for viewin
45、g colored transparencies and prints (see ANSI PH2.23).3.2.26 standard observer, nan ideal observer having visual response described by the CIE color-matching functions (see CIES 013 and Ref (3).3.2.27 CIE 1931 standard observer, nideal colorimetric observer with color-matching functions x(), y(), z(
46、) correspond-ing 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, nideal colorimetric observer with color-matching functions x10(),y10(), z10() corresponding to a field of view subtending a 10 angle on t
47、he retina; commonly called the “10 standard 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, Sz, nfactors obtained from products of the spectral power S of an illuminantand the spectral color-matching functions x, y, z (or x10, y10,
48、 z10) of an observer, usually tabulated at wavelength intervals of10 or 20 nm, used to compute tristimulus values by multiplication by the spectral reflectance, transmittance, or radiance (or thecorresponding factors) and summation.3.2.30.1 DiscussionProper account should be taken of the spectral ba
49、ndpass of the measuring instrument.4. Summary of Practice4.1 Selection of ParametersThe user of this practice must select values of the following parameters:4.1.1 ObserverSelect either the CIE 1931 standard colorimetric 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 Note 1).4.1.2 IlluminantSelect one of the CIE standard or recommended illuminants tabulated in
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