1、Designation: E1331 09Standard Test Method forReflectance Factor and Color by Spectrophotometry UsingHemispherical Geometry1This standard is issued under the fixed designation E1331; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, t
2、he year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () 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 object-c
3、olorspecimens 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 fluorescen
4、t specimens when highestaccuracy is desired. Specimens having intermediate-gloss sur-faces should preferably not be measured by use of thisgeometry.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not p
5、urport 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 regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2
6、D2244 Practice for Calculation of Color Tolerances andColor Differences from Instrumentally Measured ColorCoordinatesE179 Guide for Selection of Geometric Conditions forMeasurement of Reflection and Transmission Properties ofMaterialsE284 Terminology of AppearanceE308 Practice for Computing the Colo
7、rs of Objects byUsing the CIE SystemE805 Practice for Identification of Instrumental Methods ofColor or Color-Difference Measurement of MaterialsE991 Practice for Color Measurement of Fluorescent Speci-mens Using the One-Monochromator MethodE1164 Practice for Obtaining Spectrometric Data forObject-C
8、olor EvaluationE1345 Practice for Reducing the Effect of Variability ofColor Measurement by Use of Multiple Measurements3. Terminology3.1 Definitions:3.1.1 The definitions in Guide E179, Terminology E284,and Practice E1164 are applicable to this test method.4. Summary of Test Method4.1 This test met
9、hod provides a procedure for measuring thereflectance factors of reflecting object-color specimens byusing a spectrophotometer or spectrocolorimeter equipped witha hemispherical optical measuring system such as an integrat-ing sphere.4.2 This test method includes procedures for calibrating theinstru
10、ment and for selecting specimens suitable for precisionmeasurement.4.3 Most modern spectrophotometers have the capacity tocompute the color coordinates of the specimen immediatelyfollowing the measurement. When this is the case, the usermust select the color system, observer, and illuminant (seePrac
11、tice E308, Procedure).5. Significance and Use5.1 The most direct and accessible methods for obtainingthe color coordinates of object colors are by instrumentalmeasurement using spectrophotometers or colorimeters witheither hemispherical or bidirectional optical measuring sys-tems. This test method p
12、rovides procedures for such measure-ment by reflectance spectrophotometry using a hemisphericaloptical measuring system.5.2 This test method is especially suitable for measurementof the following types of specimens for the indicated uses(Guide E179 and Practice E805):5.2.1 All types of object-color
13、specimens to obtain data foruse in computer colorant formulation.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 approved Dec. 1, 2009. Published Decem
14、ber 2009. Originallyapproved in 1990. Last previous edition approved in 2004 as E1331 04. DOI:10.1520/E1331-09.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the s
15、tandards 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 Object-color specimens for color assessment.5.2.2.1 For the measurement of plane-surface high-glossspecimens, the specular compon
16、ent should generally be ex-cluded during the measurement.5.2.2.2 For the measurement of plane-surface intermediate-gloss specimens and of textured-surface specimens, includingtextiles, where the first-surface reflection component may bedistributed over a wide range of angles, measurement may bemade
17、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 45/0 or0/45, may lead to better correlations.5.2.2.3 For the measurement of plane-surface, low-gloss(matte) specimens, the spe
18、cular 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. For this application, the specular component shouldgenerally be included during the measurement.5.3 This test method is not
19、 recommended for measurementof the following types of specimens, for which the use ofbidirectional measurement geometry (0/45 or 45/0) is prefer-able (Guide E179):5.3.1 Object-color specimens of intermediate gloss,5.3.2 Retroreflective specimens, and5.3.3 Fluorescent specimens (Practice E991).5.3.3.
20、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 judgments. Thereafter, the method with higher visualcorrelation should be utilized.5.3.3.2 When measurements of two specimens
21、 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 in each measurement. Thishas the effect of including in both measurements all the firstsurface reflections whether diffuse or
22、 specular. These firstsurface reflections are subtracted from each other in thecolor-difference equation, and differences in the body colorremain, which is what is usually sought.6. Apparatus6.1 Spectrophotometer or spectrocolorimeter, designed forthe measurement of color coordinates of reflecting s
23、pecimensby use of integrating-sphere geometry.6.2 Calibration standards, either supplied by the instrumentmanufacturer or obtained separately, as follows (PracticeE1164, Standardization and Material Standards):6.2.1 White standard, of hemispherical reflectance factor(mandatory). (A standard of bidir
24、ectional 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 the wavelength scale;and (3) evaluating stray light (optional).6.2.3 Verification standards, (recommended) (PracticeE1164, Stan
25、dardization and Material Standards).7. Specimen Selection7.1 For highest precision and accuracy, select specimenswith the following properties:7.1.1 High material uniformity and freedom from blemishesin the area to be measured,7.1.2 Opaque specimens that have at least one plane surface,and7.1.3 Tran
26、slucent specimens that have two essentially planeand parallel surfaces and that have a standard thickness, whenone is specified (Practice E1164, Test Specimens).8. Calibration and Verification8.1 Set the instrument for inclusion or exclusion of thespecular component of reflection; set the same as wi
27、ll be usedin 8.4 (if carried out) or 9.1.8.2 Calibrate or verify the calibration of the following(Practice E1164, Standardization and Material Standards):8.2.1 Zero setting of the reflectance scale (mandatory),8.2.2 Wavelength scale (recommended), and8.2.3 Stray-light level (optional).8.3 Calibrate
28、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 Verify the accuracy of the instrumental data by measure-ment of a series of verification standards (recommended)(Practice E1164,
29、Standardization and Material Standards).Select the appropriate color scales, observer, and illuminant forthe computation of color coordinates before measurement.NOTE 1If the verification standards require a different selection ofincluding or excluding the specular component than does 9.1, select the
30、appropriate 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 to 9.2.9. Procedure9.1 Select inclusion or exclusion of the specular componentof reflection (5.2).9.2 When required, select the c
31、olor scales, observer, andilluminant for the computation of color coordinates (seePractice E308, Procedure).9.3 Select other options, such as wavelength range andinterval, when required. Follow instrument manufacturersinstructions or specified procedures.9.4 If the specimen is translucent, select sp
32、ecified black orwhite backing material. See Practice E1164, Test Specimens,for further instructions on measuring translucent specimens.9.5 Handle the specimen carefully; avoid touching the areato be measured. When necessary, clean the specimen by usingan agreed procedure.9.6 Place the specimen, with
33、 backing material if required,against the reflectance measurement port of the integratingsphere.9.7 Measure the specimen, following the instrument manu-facturers instructions.9.8 Transcribe the data required for the report, when notprinted by the instrument.E1331 09210. Calculations10.1 Perform any
34、desired calculations of color coordinatesthat are not made automatically by the instrument (PracticeD2244 and Practice E308).11. Report11.1 Report the following information:11.1.1 Specimen description (Practice E1164, Report),11.1.2 Date of measurement,11.1.3 Instrument parameters selected in 9.1-9.
35、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 interlaboratory study leading to theresults expressed in this precision and bias statement wasconducted by a Task Group in Subcommittee E12.9
36、3 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 intervals computed usingthese procedures were obtained from standard deviationsobtained by resampling the variance distribution rather tha
37、n bydirectly calculating the standard deviation of the measurementsby conventional means.12.1.1 Repeatability Samples The specimens tested con-sisted of twelve neutral and colored, high gloss ceramic tiles,BCRA/Ceram Series II. The instrument population consistedof six different instruments in one l
38、aboratory. Each specimenwas measured ten times on each instrument with the specularcomponent included. Color difference comparisons were madeonly between measurements of each tile made on the sameinstrument. The underlying data are known as the 2003 SCAIdata from the Munsell Color Science Laboratory
39、.312.1.2 RepeatabilityRepeatability conditions are definedas measurements made in the same laboratory using the sametest method by the same operator using the same equipment inthe shortest possible period of time using specimens taken fromone lot of homogeneous material. Two test results obtainedund
40、er 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 Samples The Collaborative Test-ing Services Color and Color-Difference Collaborative Ref-erence Program has surveyed the precision of color
41、 andcolor-difference measurements by sending out pairs of paintedchips exhibiting small color differences on a quarterly basissince 1971. The specimens of these surveys consist of opaquematte paint coated on white sealed paper stock and aredistributed to the respondents from the same lot of homoge-n
42、eous material. The specimens are specifically designed to beinsensitive to the specular conditions present in the instrument,and no attempt is made to report the possible geometricconditions under which the measurements are made. Table 1reports results from four specimens from these survey over thet
43、wo-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 differentmodels from nine different commercial instrument manufac-turers. The most frequently reported instrument model ac-counted for 2
44、4 % of the population of instruments. The top fourinstruments accounted for 47 % of the population, and therewere 25 instruments that represented a singular entry of thatmodel in this population.12.1.4 ReproducibilityReproducibility conditions are de-fined as measurements made in different laborator
45、ies usingdifferent equipment using the same test method, each by adifferent operator using specimens taken from one lot ofhomogeneous material. Two test results made under reproduc-ibility conditions should be considered suspect to a 95 %reproducibility limit if their values differ by more than thev
46、alues 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 accepted reference values areavailable for the specimens tested.12.3 The precision statistics for this test method must not betreated a
47、s exact mathematical quantities that are applicable toall instruments, uses, and materials. There will be times whendifferences occur that are greater than those which would bepredicted by the interlaboratory study leading to these results.Sometimes these instances occur with greater or smallerfrequ
48、ency than the 95 % probability limit would imply. If moreprecise information is required in specific circumstances, thoselaboratories directly involved in a material comparison mustconduct interlaboratory studies aimed at the material of inter-est.12.4 The user is also referred to Practice E1345 for
49、 infor-mation on one potential method of increasing the precision ofones measurements.13. Keywords13.1 color; hemispherical geometry; reflectance; reflectancefactor; 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, http:/www.iscc.org.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
