1、Designation: E 1331 04Standard Test Method forReflectance Factor and Color by Spectrophotometry UsingHemispherical Geometry1This standard is issued under the fixed designation E 1331; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、 the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method describes the instrumental measure-ment of the reflection properties and color of objec
3、t-colorspecimens by the use of a spectrophotometer or spectrocolo-rimeter with a hemispherical optical measuring system, such asan integrating sphere.1.2 The test method is suitable for use with most object-color specimens. However, it should not be used for retrore-flective specimens or for fluores
4、cent specimens when highestaccuracy is desired. Specimens having intermediate-gloss sur-faces should preferably not be measured by use of thisgeometry.1.3 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
5、 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:2D 2244 Practice for Calculation of Color Differences fromInstrumentally Measured Color CoordinatesE 179 Guide for Selecti
6、on of Geometric Conditions forMeasurement of Reflection and Transmission Properties ofMaterialsE 284 Terminology of AppearanceE 308 Practice for Computing the Colors of Objects byUsing the CIE SystemE 805 Practice for Identification of Instrumental Methods ofColor or Color-Difference Measurement of
7、MaterialsE 991 Practice for Color Measurement of FluorescentSpecimensE 1164 Practice for Obtaining Spectrophotometric Data forObject-Color EvaluationE 1345 Practice for Reducing the Effect of Variability ofColor Measurement by Use of Multiple Measurements3. Terminology3.1 Definitions:3.1.1 The defin
8、itions in Guide E 179, Terminology E 284,and Practice E 1164 are applicable to this test method.4. Summary of Test Method4.1 This test method provides a procedure for measuring thereflectance factors of reflecting object-color specimens byusing a spectrophotometer or spectrocolorimeter equipped with
9、a hemispherical optical measuring system such as an integrat-ing sphere.4.2 This test method includes procedures for calibrating theinstrument and for selecting specimens suitable for precisionmeasurement.4.3 Most modern spectrophotometers have the capacity tocompute the color coordinates of the spe
10、cimen immediatelyfollowing the measurement. When this is the case, the usermust select the color system, observer, and illuminant (seePractice E 308, Procedure).5. Significance and Use5.1 The most direct and accessible methods for obtainingthe color coordinates of object colors are by instrumentalme
11、asurement using spectrophotometers or colorimeters witheither hemispherical or bidirectional optical measuring sys-tems. This test method provides procedures for such measure-ment by reflectance spectrophotometry using a hemisphericaloptical measuring system.5.2 This test method is especially suitab
12、le for measurementof the following types of specimens for the indicated uses(Guide E 179 and Practice E 805):5.2.1 All types of object-color specimens to obtain data foruse in computer colorant formulation.5.2.2 Object-color specimens for color assessment.5.2.2.1 For the measurement of plane-surface
13、 high-glossspecimens, the specular component should generally be ex-cluded during the measurement.1This test method is under the jurisdiction of ASTM Committee E12 on Colorand Appearance and is the direct responsibility of Subcommittee E12.02 onSpectrophotometry and Colorimetry.Current edition appro
14、ved June 1, 2004. Published July 2004. Originally approvedin 1990. Last previous edition approved in 2003 as E 1331 96 (2003).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information,
15、 refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2.2.2 For the measurement of plane-surface intermediate-gloss specimens and of textured-surface specimens, includingte
16、xtiles, where the first-surface reflection component may bedistributed over a wide range of angles, measurement may bemade with the specular component included, but the resultingcolor coordinates may not correlate best with visual judgmentsof the color. The use of bidirectional geometry, such as 45/
17、0 or0/45, may lead to better correlations.5.2.2.3 For the measurement of plane-surface, low-gloss(matte) specimens, the specular component may either beexcluded or included, as no significant difference in the resultsshould be apparent.5.2.3 Specimens with bare metal surfaces for color assess-ment.
18、For this application, the specular component shouldgenerally be included during the measurement.5.3 This test method is not recommended for measurementof the following types of specimens, for which the use ofbidirectional measurement geometry (0/45 or 45/0) is prefer-able (Guide E 179):5.3.1 Object-
19、color specimens of intermediate gloss,5.3.2 Retroreflective specimens, and5.3.3 Fluorescent specimens (Practice E 991).5.3.3.1 When there is doubt as to whether the specularcomponent of reflection should be included or excluded, bothmeasurements should be made, and the results correlated withvisual
20、judgments. Thereafter, the method with higher visualcorrelation should be utilized.5.3.3.2 When measurements of two specimens whose gloss,or texture, are substantially different from each other, are to beutilized in a color-difference comparison, generally the specu-lar component should be included
21、in each measurement. Thishas the effect of including in both measurements all the firstsurface reflections whether diffuse or specular. These firstsurface reflections are subtracted from each other in thecolor-difference equation, and differences in the body colorremain, which is what is usually sou
22、ght.6. Apparatus6.1 Spectrophotometer or spectrocolorimeter, designed forthe measurement of color coordinates of reflecting specimensby use of integrating-sphere geometry.6.2 Calibration standards, either supplied by the instrumentmanufacturer or obtained separately, as follows (PracticeE 1164, Stan
23、dardization and Material Standards):6.2.1 White standard, of hemispherical reflectance factor(mandatory). (A standard of bidirectional reflectance factor isnot satisfactory and should not be used.)6.2.2 Calibration standards, for (1) setting or verifying zeroon the photometric scale; (2) verifying t
24、he wavelength scale;and (3) evaluating stray light (optional).6.2.3 Verification standards, (recommended) (PracticeE 1164, Standardization and Material Standards).7. Specimen Selection7.1 For highest precision and accuracy, select specimenswith the following properties:7.1.1 High material uniformity
25、 and freedom from blemishesin the area to be measured,7.1.2 Opaque specimens that have at least one plane surface,and7.1.3 Translucent specimens that have two essentially planeand parallel surfaces and that have a standard thickness, whenone is specified (Practice E 1164, Test Specimens).8. Calibrat
26、ion and Verification8.1 Set the instrument for inclusion or exclusion of thespecular component of reflection; set the same as will be usedin 8.4 (if carried out) or 9.1.8.2 Calibrate or verify the calibration of the following(Practice E 1164, Standardization and Material Standards):8.2.1 Zero settin
27、g of the reflectance scale (mandatory),8.2.2 Wavelength scale (recommended), and8.2.3 Stray-light level (optional).8.3 Calibrate the full-scale value of the reflectance scale ofthe instrument by use of the white reflectance standard (man-datory). Follow the instrument manufacturers instructions.8.4
28、Verify the accuracy of the instrumental data by measure-ment of a series of verification standards (recommended)(Practice E 1164, Standardization and Material Standards).Select the appropriate color scales, observer, and illuminant forthe computation of color coordinates before measurement.NOTE 1If
29、the verification standards require a different selection ofincluding or excluding the specular component than does 9.1, select theappropriate condition for measurement of the verification standards in 8.1,complete 8.4; select the correct setting for specimen measurement (9.1),repeat 8.3, and proceed
30、 to 9.2.9. Procedure9.1 Select inclusion or exclusion of the specular componentof reflection (5.2).9.2 When required, select the color scales, observer, andilluminant for the computation of color coordinates (seePractice E 308, Procedure).9.3 Select other options, such as wavelength range andinterva
31、l, when required. Follow instrument manufacturersinstructions or specified procedures.9.4 If the specimen is translucent, select specified black orwhite backing material. See Practice E 1164, Test Specimens,for further instructions on measuring translucent specimens.9.5 Handle the specimen carefully
32、; avoid touching the areato be measured. When necessary, clean the specimen by usingan agreed procedure.9.6 Place the specimen, with backing material if required,against the reflectance measurement port of the integratingsphere.9.7 Measure the specimen, following the instrument manu-facturers instru
33、ctions.9.8 Transcribe the data required for the report, when notprinted by the instrument.10. Calculations10.1 Perform any desired calculations of color coordinatesthat are not made automatically by the instrument (PracticeD 2244 and Practice E 308).E133104211. Report11.1 Report the following inform
34、ation:11.1.1 Specimen description (Practice E 1164, Report),11.1.2 Date of measurement,11.1.3 Instrument parameters selected in 9.1-9.4, and11.1.4 Measurement results, in the form of tables of reflec-tance factor versus wavelength or color-scale values.12. Precision and Bias12.1 PrecisionThe interla
35、boratory study leading to theresults expressed in this precision and bias statement wasconducted by a Task Group in Subcommittee E12.93 onPrecision and Bias during the period July to September 2003.The results in 12.1.2 and 12.1.4 were obtained by bootstrapprocedures. The statistical confidence inte
36、rvals computed usingthese procedures were obtained from standard deviationsobtained by resampling the variance distribution rather than bydirectly calculating the standard deviation of the measurementsby conventional means.12.1.1 Repeatability Samples The specimens tested con-sisted of twelve neutra
37、l and colored, high gloss ceramic tiles,BCRA/Ceram Series II. The instrument population consistedof six different instruments in one laboratory. Each specimenwas measured ten times on each instrument with the specularcomponent included. Color difference comparisons were madeonly between measurements
38、 of each tile made on the sameinstrument. The underlying data are known as the 2003 SCAIdata from the Munsell Color Science Laboratory.312.1.2 RepeatabilityRepeatability conditions are definedas measurements made in the same laboratory using the sametest method by the same operator using the same eq
39、uipment inthe shortest possible period of time using specimens taken fromone lot of homogeneous material. Two test results obtainedunder repeatability conditions should be considered suspect toa 95 % repeatability limit if their values differ by more than0.08 unit, DE*ab.12.1.3 Reproducibility Sampl
40、es The Collaborative Test-ing Services Color and Color-Difference Collaborative Ref-erence Program has surveyed the precision of color andcolor-difference measurements by sending out pairs of paintedchips exhibiting small color differences on a quarterly basissince 1971. The specimens of these surve
41、ys consist of opaquematte paint coated on white sealed paper stock and aredistributed to the respondents from the same lot of homoge-neous material. The specimens are specifically designed to beinsensitive to the specular conditions present in the instrument,and no attempt is made to report the poss
42、ible geometricconditions under which the measurements are made. Table 1reports results from four specimens from these survey over thetwo-year period from 2000 to 2002. Approximately 250instruments are reported in each survey. The instrument popu-lation of one of these four surveys consisted of 55 di
43、fferentmodels from nine different commercial instrument manufac-turers. The most frequently reported instrument model ac-counted for 24 % of the population of instruments. The top fourinstruments accounted for 47 % of the population, and therewere 25 instruments that represented a singular entry of
44、thatmodel in this population.12.1.4 ReproducibilityReproducibility conditions are de-fined as measurements made in different laboratories usingdifferent equipment using the same test method, each by adifferent operator using specimens taken from one lot ofhomogeneous material. Two test results made
45、under reproduc-ibility conditions should be considered suspect to a 95 %reproducibility limit if their values differ by more than thevalues given in Table 1 under the column headed “95 %Reproducibility Limits.”12.2 BiasIt is not possible to determine the bias, if any, ofthis test method because no a
46、ccepted reference values areavailable for the specimens tested.12.3 The precision statistics for this test method must not betreated as exact mathematical quantities that are applicable toall instruments, uses, and materials. There will be times whendifferences occur that are greater than those whic
47、h would bepredicted by the interlaboratory study leading to these results.Sometimes these instances occur with greater or smallerfrequency than the 95 % probability limit would imply. If moreprecise information is required in specific circumstances, thoselaboratories directly involved in a material
48、comparison mustconduct interlaboratory studies aimed at the material of inter-est.12.4 The user is also referred to Practice E 1345 forinformation on one potential method of increasing the preci-sion of ones measurements.13. Keywords13.1 color; hemispherical geometry; reflectance; reflectancefactor;
49、 spectrophotometry3Proceedings 2003 ISCC-FSCT Symposium on Color and Appearance Instru-mentation (SCAI), Chicago, IL, April 14-15, 2003, available from Inter-SocietyColor Council, 11491 Sunset Hills Rd., Reston, VA, 21190.TABLE 1 Specimens, Colorimetric Values, and 95 %Reproducibility LimitsSample # Mean L* Mean a* Mean b* 95 % ReproducibilityLimits in units of DE*abA01 41.90 4.89 -13.97 0.35C01 70.00 23.36 -10.20 0.75A11 63.62 18.84 6.78 0.54C11 85.38 1.40 50.42 0.76E1331043ASTM International takes no position respecting the validity of any patent rights asserted in conn
