ASTM D523-1989(1999) Standard Test Method for Specular Gloss《镜面光泽的试验方法》.pdf

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1、Designation: D 523 89 (Reapproved 1999)Standard Test Method forSpecular Gloss1This standard is issued under the fixed designation D 523; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parenth

2、eses 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.1. Scope1.1 This test method covers the measurement of the speculargloss of nonmet

3、allic specimens for glossmeter geometries of60, 20, and 85 (1-7).21.2 The values stated in inch-pound units are to be regardedas the standard. The values given in parentheses are forinformation only.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its

4、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:D 823 Practices for Producing Films of Uniform Thicknessof Paint, Varnish,

5、 and Related Products on Test Panels3D 3964 Practice for Selection of Coating Specimens forAppearance Measurements3D 3980 Practice for Interlaboratory Testing of Paint andRelated Materials4D 4039 Test Method for Reflection Haze of High-GlossSurfaces3E97 Test Method for Directional Reflectance Factor

6、, 45-deg 0-deg, of Opaque Specimens by Broad-Band FilterReflectometry5E 430 Test Method for Measurement of Gloss of High-Gloss Surfaces by Goniophotometry33. Terminology3.1 Definitions:3.1.1 relative luminous reflectance factorthe ratio of theluminous flux reflected from a specimen to the luminous f

7、luxreflected from a standard surface under the same geometricconditions. For the purpose of measuring specular gloss, thestandard surface is polished glass.3.1.2 specular glossthe relative luminous reflectance fac-tor of a specimen in the mirror direction.4. Summary of Test Method4.1 Measurements ar

8、e made with 60, 20, or 85 geometry(8, 9). The geometry of angles and apertures is chosen so thatthese procedures may be used as follows:4.1.1 The 60 geometry is used for intercomparing mostspecimens and for determining when the 20 geometry may bemore applicable.4.1.2 The 20 geometry is advantageous

9、for comparingspecimens having 60 gloss values higher than 70.4.1.3 The 85 geometry is used for comparing specimensfor sheen or near-grazing shininess. It is most frequentlyapplied when specimens have 60 gloss values lower than 10.5. Significance and Use5.1 Gloss is associated with the capacity of a

10、surface toreflect more light in some directions than in others. Thedirections associated with mirror (or specular) reflection nor-mally have the highest reflectances. Measurements by this testmethod correlate with visual observations of surface shininessmade at roughly the corresponding angles.5.1.1

11、 Measured gloss ratings by this test method are ob-tained by comparing the specular reflectance from the speci-men to that from a black glass standard. Since specularreflectance depends also on the surface refractive index of thespecimen, the measured gloss ratings change as the surfacerefractive in

12、dex changes. In obtaining the visual gloss ratings,however, it is customary to compare the specular reflectancesof two specimens having similar surface refractive indices.Since the instrumental ratings are affected more than the visualratings by changes in surface refractive index, non-agreementbetw

13、een visual and instrumental gloss ratings can occur whenhigh gloss specimen surfaces differing in refractive index arecompared.5.2 Other visual aspects of surface appearance, such asdistinctness of reflected images, reflection haze, and texture,are frequently involved in the assessment of gloss (1),

14、 (6), (7).Test Method E 430 includes techniques for the measurement of1This test method is under the jurisdiction of ASTM Committee E12 on Colorand Appearance and is the direct responsibility of Subcommittee E12.03 onGeometry.Current edition approved March 31, 1989. Published May 1989. Originallypub

15、lished as D 523 39 T. Last previous edition D 523 85e1.2The boldface numbers in parentheses refer to the list of references at the end ofthis test method.3Annual Book of ASTM Standards, Vol 06.01.4Discontinued; see 1997 Annual Book of ASTM Standards, Vol 06.01.5Discontinued; see 1992 Annual Book of

16、ASTM Standards, Vol 14.02.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.both distinctness-of-image gloss and reflection haze. TestMethod D 4039 provides an alternative procedure for measur-ing reflection haze.5.3 Little information

17、 about the relation of numerical-to-perceptual intervals of specular gloss has been published.However, in many applications the gloss scales of this testmethod have provided discriminations between coated speci-mens that have agreed well with visual discriminations of gloss(10).5.4 When specimens di

18、ffering widely in perceived gloss orcolor, or both, are compared, nonlinearity may be encounteredin the relationship between visual gloss difference ratings andinstrumental gloss reading differences.6. Apparatus6.1 Instrumental ComponentsThe apparatus shall consistof an incandescent light source fur

19、nishing an incident beam,means for locating the surface of the specimen, and a receptorlocated to receive the required pyramid of rays reflected by thespecimen. The receptor shall be a photosensitive device re-sponding to visible radiation.6.2 Geometric ConditionsThe axis of the incident beamshall b

20、e at one of the specified angles from the perpendicular tothe specimen surface. The axis of the receptor shall be at themirror reflection of the axis of the incident beam. The axis ofthe incident beam and the axis of the receptor shall be within0.1 of the nominal value indicated by the geometry. Wit

21、h a flatpiece of polished black glass or other front-surface mirror inthe specimen position, an image of the source shall be formedat the center of the receptor field stop (receptor window). Thelength of the illuminated area of the specimen shall be not morethan one third of the distance from the ce

22、nter of this area to thereceptor field stop. The dimensions and tolerance of the sourceand receptor shall be as indicated in Table 1. The angulardimensions of the receptor field stop are measured from thereceptor lens in a collimated-beam-type instrument, as illus-trated in Fig. 1, and from the test

23、 surface in a converging-beam-type instrument, as illustrated in Fig. 2. See Fig. 1 andFig. 2 for a generalized illustration of the dimensions. Thetolerances are chosen so that errors in the source and receptorapertures do not produce an error of more than one gloss unitat any point on the scale (5)

24、.6.2.1 The important geometric dimensions of any specular-gloss measurement are:6.2.1.1 Beam axis angle(s), usually 60, 20, or 85.6.2.1.2 Accepted angular divergences from principal rays(degree of spreading or diffusion of the reflected beam).NOTE 1The parallel-beam glossmeters possess the better un

25、iformityof principle-ray angle of reflection, but the converging-beam glossmeterspossess the better uniformity in extent of angular divergence accepted formeasurement.NOTE 2PolarizationAn evaluation of the impact of polarization ongloss measurement has been reported (11). The magnitude of the polar-

26、ization error depends on the difference between the refractive indices ofspecimen and standard, the angle of incidence, and the degree ofpolarization. Because the specimen and standard are generally quitesimilar optically, measured gloss values are little affected by polarization.6.3 VignettingThere

27、 shall be no vignetting of rays that liewithin the field angles specified in Table 1.6.4 Spectral ConditionsResults should not differ signifi-cantly from those obtained with a source-filter photocellcombination that is spectrally corrected to yield CIE luminousefficiency with CIE source C. Since spe

28、cular reflection is, ingeneral, spectrally nonselective, spectral corrections need to beapplied only to highly chromatic, low-gloss specimens uponagreement of users of this test method.6.5 Measurement MechanismThe receptor-measurementmechanism shall give a numerical indication that is propor-tional

29、to the light flux passing the receptor field stop with61 % of full-scale reading.7. Reference Standards7.1 Primary StandardsHighly polished, plane, black glasswith a refractive index of 1.567 for the sodium D line shall beassigned a specular gloss value of 100 for each geometry. Thegloss value for g

30、lass of any other refractive index can becomputed from the Fresnel equation (5). For small differencesin refractive index, however, the gloss value is a linear functionof index, but the rate of change of gloss with index is differentfor each geometry. Each 0.001 increment in refractive indexproduces

31、 a change of 0.27, 0.16, and 0.016 in the gloss valueassigned to a polished standard for the 20, 60, and 85geometries, respectively. For example, glass of index 1.527would be assigned values of 89.2, 93.6, and 99.4, in order ofincreasing geometry.NOTE 3Polished black glass has been reported to chang

32、e in refractiveindex with time largely due to chemical contamination (10). The originalvalues can be restored by optical polishing with cerium oxide. A wedge ofhigh-purity quartz provides a more stable reference standard than glass.7.2 Working StandardsCeramic tile, depolished groundopaque glass, em

33、ery paper, and other semigloss materialshaving hard and uniform surfaces are suitable when calibratedagainst a primary standard on a glossmeter known to meet therequirements of this test method. Such standards should bechecked periodically for constancy by comparing with primarystandards.7.3 Store s

34、tandards in a closed container when not in use.Keep them clean and away from any dirt that might scratch ormar their surfaces. Never place standards face down on asurface that may be dirty or abrasive. Always hold standards atthe side edges to avoid getting oil from the skin on the standardTABLE 1 A

35、ngles and Relative Dimensions of Source Image andReceptorsIn Plane ofMeasurementPerpendicular toPlane of Measurementu, 2 tan u/2RelativeDimensionu, 2tanu/2RelativeDimensionSource image 0.75 0.0131 0.171 2.5 0.0436 0.568Tolerance 6 0.25 0.0044 0.057 0.5 0.0087 0.11460 receptor 4.4 0.0768 1.000 11.7 0

36、.2049 2.668Tolerance6 0.1 0.0018 0.023 0.2 0.0035 0.04620 receptor 1.8 0.0314 0.409 3.6 0.0629 0.819Tolerance 6 0.05 0.0009 0.012 0.1 0.0018 0.02385 receptor 4.0 0.0698 0.909 6.0 0.1048 1.365Tolerance6 0.3 0.0052 0.068 0.3 0.0052 0.068D 523 89 (1999)2surface. Clean the standards in warm water and a

37、milddetergent solution brushing gently with a soft nylon brush. (Donot use soap solutions to clean standards, because they canleave a film.) Rinse standards in hot running water (tempera-ture near 150F (65C) to remove detergent solution, followedby a final rinse in distilled water. Do not wipe stand

38、ards. Thepolished black glass high-gloss standard may be dabbed gentlywith a lint-free paper towel or other lint-free absorbentmaterial. Place the rinsed standards in a warm oven to dry.8. Preparation and Selection of Test Specimens8.1 This test method does not cover preparation techniques.Whenever

39、a test for gloss requires the preparation of testspecimens, use the procedures given in Practice D 823.NOTE 4To determine the maximum gloss obtainable from a testmaterial, such as a paint or varnish, use Methods B or C of Practice D 823.8.2 Select specimens in accordance with Practice D 3964.9. Inst

40、rument Calibration9.1 Operate the glossmeter in accordance with the manufac-turers instructions.9.2 Verify the instrument zero by placing a black cavity inthe specified position. If the reading is not within 60.1 of zero,subtract it algebraically from subsequent readings or adjust theinstrument to r

41、ead zero.9.3 Calibrate the instrument at the start and completion ofevery period of glossmeter operation, and during the operationat sufficiently frequent intervals to assure that the instrumentresponse is practically constant. To calibrate, adjust the instru-ment to read correctly the gloss of a hi

42、ghly polished standard,properly positioned and oriented, and then read the gloss of aworking standard in the mid-gloss range. If the instrumentreading for the second standard does not agree within one unitof its assigned values, check cleanliness and repeat. If theinstrument reading for the second s

43、tandard still does not agreewithin one unit of its assigned value, repeat with anothermid-range standard. If the disparity is still more than one unit,do not use the instrument without readjustment, preferably bythe manufacturer.10. Procedure10.1 Position each specimen in turn beneath (or on) theglo

44、ssmeter. For specimens with brush marks or similar textureeffects, place them in such a way that the directions of themarks are parallel to the plane of the axes of the incident andreflected beams.10.2 Take at least three readings ona3by6-in. (75 by150-mm) area of the test specimen. If the range is

45、greater thantwo gloss units, take additional readings and calculate the meanafter discarding divergent results as in the section on Test forFIG. 1 Diagram of Parallel-Beam Glossmeter Showing Apertures and Source Mirror-Image PositionFIG. 2 Diagram of Converging-Beam Glossmeter Showing Apertures and

46、Source Mirror-Image PositionD 523 89 (1999)3Outliers of Practice D 3980. For larger specimens, take aproportionately greater number of readings.11. Diffuse Correction11.1 Apply diffuse corrections only upon agreement be-tween the producer and the user. To apply the correction,subtract it from the gl

47、ossmeter reading. To measure thecorrection, illuminate the specimen perpendicularly and viewat the incident angle with the receiver aperture specified in 6.2for the corresponding geometry. To compute the correction,multiply the 45, 0 directional reflectance of the specimen,determined in accordance w

48、ith Test Method E97,bytheeffective fraction of the luminous flux reflected by the perfectdiffuse reflector and accepted by the receiver aperture. Theluminous flux entering the receiver aperture from the perfectwhite diffusor would give the following gloss indications foreach of the geometries:Geomet

49、ry, Gloss of Perfect White Diffuser60 2.520 1.285 0.0312. Report12.1 Report the information following:12.1.1 Mean specular gloss readings and the geometry used.12.1.2 If uniformity of surface is of interest, the presence ofany specimen that exhibits gloss readings varying by more than5 % from their mean.12.1.3 Where preparation of the test specimen has beennecessary, a description or identification of the method ofpreparation.12.1.4 Manufacturers name and model designation of theglossmeter.12.1.5 Working standard or standards of gloss used.13.