1、Designation: D 3134 97 (Reapproved 2008)1Standard Practice forEstablishing Color and Gloss Tolerances1This standard is issued under the fixed designation D 3134; 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.1NOTECorrections were made editorially in Footnote 4, 7.2.1, and Section 12 in December 2008.INTRODUCTIONPermissible color and gloss deviat
3、ions from a standard are generally dependent upon the colordiscrimination of the observer, on the lighting and surround in which the material is viewed, and onspecial considerations related to the design, manufacture, and practical usage of the colored materialor object. The tolerances, therefore, m
4、ay be influenced by economic, technical, psychological, andpractical requirements. In many circumstances, acceptability of color and gloss deviations from astandard may differ appreciably from the perceptibility of deviations such as on-tone fadingpreferences, large tolerances for luminance variatio
5、n, nongreen bias, or nonyellow bias. With properallowances, perceptibility data can be used as an aid to develop permissible tolerances. Finally, thesum of all these considerations should result in a specification acceptable to both buyer and seller.1. Scope1.1 This practice describes a procedure fo
6、r establishingtolerances and evaluating the color and gloss of specimens withrespect to specified standards. This practice is appropriate fornonfluorescent opaque specimens.1.2 This practice does not indicate the extent of tolerances,but gives guidance on how they can be set. For productspecificatio
7、n, the tolerances between specimens and the speci-fied standard should be agreed upon between the purchaser andthe seller.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 standard to establish appro-
8、priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 523 Test Method for Specular GlossD 1535 Practice for Specifying Color by the Munsell Sys-temD 1729 Practice for Visual Appraisal of Colors and Colo
9、rDifferences of Diffusely-Illuminated Opaque MaterialsD 2244 Practice for Calculation of Color Tolerances andColor Differences from Instrumentally Measured ColorCoordinatesD 3964 Practice for Selection of Coating Specimens forAppearance MeasurementsD 4449 Test Method for Visual Evaluation of Gloss D
10、iffer-ences Between Surfaces of Similar AppearanceD 5531 Guide for Preparation, Maintenance, and Distribu-tion of Physical Product Standards for Color and Geomet-ric Appearance of CoatingsE 284 Terminology of AppearanceE 308 Practice for Computing the Colors of Objects byUsing the CIE SystemE 312 Pr
11、actice for Description and Selection of Conditionsfor Photographing Specimens Using Analog (Film) Cam-eras and Digital Still Cameras (DSC)E 805 Practice for Identification of Instrumental Methods ofColor or Color-Difference Measurement of MaterialsE 1164 Practice for Obtaining Spectrometric Data for
12、Object-Color EvaluationE 1331 Test Method for Reflectance Factor and Color bySpectrophotometry Using Hemispherical GeometryE 1345 Practice for Reducing the Effect of Variability ofColor Measurement by Use of Multiple MeasurementsE 1349 Test Method for Reflectance Factor and Color bySpectrophotometry
13、 Using Bidirectional (45:0 or 0:45)GeometryE 1360 Practice for Specifying Color by Using the Optical1This practice is under the jurisdiction of ASTM Committee E12 on Color andAppearance and is the direct responsibility of Subcommittee E12.11 on VisualMethods.Current edition approved Dec. 1, 2008. Pu
14、blished December 2008. Originallyapproved in 1972. Last previous edition approved in 2003 as D 3134 97 (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, refer to the st
15、andards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Society of America Uniform Color Scales SystemE 1499 Guide for Selection, Evaluation, and Training ofObserversE 1541 Practice for Specif
16、ying and Matching Color Usingthe Colorcurve System3E 1708 Practice for Electronic Interchange of Color andAppearance Data2.2 CIE Publication:No. CIE S 014-4/E2007 Colorimetry 2nd ed.43. Terminology3.1 DefinitionsFor definitions of terms related to thispractice see Terminology E 284.4. Summary of Pra
17、ctice4.1 This practice consists of recommendations for the se-lection of a standard, the necessary physical measurements toassess the permanence of the standard to reproduce it whenneeded, and to establish tolerances.4.2 Recommendations are given for the determination of theconformance of a specimen
18、 to preestablished color and glosstolerances by instrumental or visual means.5. Significance and Use5.1 Color specifications are centered around exact positionsin color space. Correspondingly, gloss specifications are cen-tered around an exact position on the gloss scale. Because it isdifficult to a
19、chieve these exact positions repeatedly, it isnecessary to specify tolerances that are acceptable to both thebuyer and the seller. This practice details the procedure foraccomplishing this goal.6. Specimens6.1 The exact method of preparation of the specimen shallbe agreed upon between the purchaser
20、and the seller. However,for the highest precision in instrumental measurements thespecimens should be opaque, uniform in color, plane, anduniform in texture. The specimens should be relatively perma-nent, and capable of being cleaned. Preferred sizes of speci-mens for visual evaluation are given in
21、Practice D 1729, thespecific size being governed by the use of the specimens.7. Procedure7.1 Selection and Specification of Color and Gloss Stan-dard:7.1.1 Select a standard in accordance with Practice D 3964that is preferably the same type of material as the specimens tobe evaluated for color or gl
22、oss, or both. Prepare, in sufficientquantity, secondary standards in accordance with GuideD 5531 that are representative of the desired color and gloss, inthe permanent material. Standards should have the samespectral characteristics as the manufactured product. This isusually accomplished by use of
23、 the same colorant composition,incorporated in the same manner into the same material. Thestandard should have the same texture as the manufacturedproduct.7.1.1.1 In order to obtain a permanent record, use PracticeE 805 and either Test Method E 1331 or Test Method E 1349 tocorrectly identify the ins
24、trumental measurement method. Mea-sure the color in accordance with Practices E 1164 and E 805.Report the color as described in Practice E 308. Do this even ifthe standard is textured. (If the standard is textured, note thetexture orientation during measurement.) The variability of themeasurements d
25、ue to texture may be reduced by following therecommendations outlined in Practice E 1345.7.1.1.2 Visual Color AssessmentUse Guide E 1499 toselect an observer for the assessment. Assess and specify thecolor in terms of a color system described in Practices D 1535,E 1360,orE 1541.7.1.1.3 Measure the g
26、loss in accordance with Test MethodD 523, or evaluate it in accordance with Test Method D 4449.7.1.1.4 Employ photography for permanently recording theappearance of the surface texture (see Practice E 312). WhilePractice D 3134 does not deal with texture tolerances orspecifications, it should be rec
27、ognized that significant differ-ences in surface texture between standard and test specimenssignificantly affect both color and gloss, whether examinedvisually or instrumentally. In the case of visual evaluation ofthe effect of color and gloss, differences can be minimized bystrict adherence to reco
28、mmended illuminating and viewinggeometry (see Practice D 1729).7.2 Selection and Specification of Color Tolerances:7.2.1 The purchaser and the seller shall agree on colortolerances with respect to a previously selected standard and onthe color scales in which they are expressed. Selection of themagn
29、itude and direction of color tolerances shall be based oncareful consideration of all applicable factors. For example,tolerances may be selected on the basis of perceptibility of themagnitude of color difference, rejection of or closer limits oncertain directions of color difference, and costs of co
30、ntrollingthe magnitude and direction of color difference. Recommen-dations on color scales appear in CIE Publication No. CIE S014-4/E2007 and Practice E 308.7.2.1.1 Express color differences between the specimen andthe standard in terms of a set of three independent parameters.The CIE 1976 L*a*b* (C
31、IELAB) approximately uniform colorspace and color difference equations have been recommendedfor use by the International Commission on Illumination (CIE).See Practice D 2244 and Practice E 308. While this colormetric (CIELAB) is convenient for expressing color differ-ences, it must be understood tha
32、t a given calculated colordifference in one region of color space may not represent thesame visual difference in other regions of color space.7.2.2 Gloss differences can affect instrumental measurementof color differences. Large gloss differences between visuallyidentical colors can cause their colo
33、r measurements to exhibitlarger color differences than in fact exist. When using historicaldata to establish color tolerances, exercise care to limit thespecimens to those that have quite similar gloss values. Whenestablishing gloss tolerances, be aware that changes in glossvalues may have an effect
34、 upon color measurements.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.4Available from CIE (International Commission on Illumination)webshop, http:/ perhaps it will be an ovoidinstead of an ellipse; its major axis may deviate from thedirection of cons
35、tant hue; and the standard color may be farfrom its center. Frequently when it is necessary to set colortolerances, the amount of historical accept-reject data will betoo modest for this purpose. It is therefore necessary to monitortolerances, once set, to ensure that they appropriately addressthe c
36、olor quality control requirement.7.2.9 When tolerance standards are prepared to illustrate thecolor in the hue, lightness, and saturation or chroma attributesof color space and to allow visual interpretation of theconformity of color, inspection should be under specified lightsources following the r
37、ecommendations in Practice D 1729.Gonioapparent coatings or materials require special method-ologies for viewing and measurement.7.3 Selection and Specification of Gloss Tolerances:7.3.1 The gloss tolerances around the gloss of the standardmay be expressed in gloss units (See Test Method D 523)orasa
38、 percent.7.3.2 With few exceptions, the visual gloss tolerance will besymmetrical around the nominal value of the standard. It willbe necessary to determine experimentally the instrumentalreadings that correspond to the required visual differences.7.3.3 When the gloss desired is at or near the maxim
39、um orminimum gloss attainable, it is customary to specify a singlegloss reading and the direction in which the data may departfrom it. For example, for a very high gloss requirement, oneNOTE 1Hue angle is measured in degrees starting with hab=0 inthe + a* (red) direction and increasing counterclockw
40、ise. Chroma ismeasured as the length of the line from the neutral point (a*=b*=0)tothe sample point. Sample Point 2 has a larger value of habthan Point 1 andtherefore is yellower in hue. Point 2 also has a smaller value of Cab* thanPoint 1 and is therefore lower in chroma or duller.NOTE 2Original so
41、urce is Billmeyer, F. W., Jr., and Saltzman, M.,Principles of Color Technology, 2nd ed., John Wiley and Sons, New York,NY, 1981. (Reprinted by permission of John Wiley exact color matches are seldom seen. A modest reduction intolerance can cause an important increase in difficulty ofmatching, with a
42、 corresponding increase in cost.7.4.4 Liberal tolerances are used, typically, when the prod-uct is very small, the material used is difficult to coloraccurately or the products exhibit large variations in otherappearance attributes (texture or gloss) which tend to maskcolor differences or are seen o
43、nly from a distance. Examplesare color-coded electronic parts and wires, colored masonry,and porcelain insulators on poles. Tight tolerances are used forfinishes on consumer products, such as, automobiles and majorappliances. Tentative tolerances can be based on the guidelinesgiven in 7.4.5 and 7.4.
44、6.7.4.5 Color Tolerances:7.4.5.1 Symmetrical color tolerances around a standardcolor can be specified in terms of the overall color difference(DE) in CIELAB units (see Practice D 2244 and PracticeE 308), as shown in the following example. These are ex-amples only, not recommendations.ToleranceDesign
45、ationCIELAB Color Difference, DEA 1.0B 2.0C 3.0In this example the A tolerance is the tightest, while the Ctolerance is the most liberal.(a) Chromaticity TolerancesNOTE 1The standard color is at the 0,0 point and the tolerance ellipses define permissible differences from it. Fig. 2(a) shows chromati
46、city tolerancesin a* and b*; Fig. 3(b) shows lightness tolerances in L*, with a* data also shown.FIG. 2 Plots of Instrumental Results on Color Specimens Along With Their Visual Acceptability RatingsD 3134 97 (2008)147.4.5.2 The most frequently encountered industrial toler-ances provide for different
47、 limits for the visual color attributesof hue, lightness, and saturation or chroma. Asymmetricalcolor tolerances around a standard color represent the usualcase, because there are important differences between equallyperceptible and equally acceptable differences. While it isbeyond the scope of this
48、 practice to discuss these differentialsin detail, it can be stated that the usual tolerance specificationrequires hue tolerances to be relatively tighter, and lightnesstolerances to be less tight, with saturation or chroma tolerancesbetween these. Variations from this exist.7.4.5.3 Tolerances are p
49、referably set experimentally byclassifying specimens visually against a visual standard, thenmeasuring the specimens and standard and plotting the valueson a CIELAB Da*, Db* constant-lightness (L*) plane. Theexpected result is that visually acceptable specimens will begrouped about the standard (plotted as Da*=Db* = 0), so thata line enclosing them forms a figure on the Da*Db* plane.7.4.5.4 A lightness tolerance DL* must also be established.A rough approximation is the lightness difference DL* forcolors that mat
