1、Designation: D523 14 (Reapproved 2018)Standard Test Method forSpecular Gloss1This standard is issued under the fixed designation D523; 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 parenthes
2、es 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.1. Scope1.1 This test method covers the measurement of the speculargloss of nonm
3、etallic specimens for glossmeter geometries of60, 20, and 85 (1-7).21.2 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 This standard
4、 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-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This interna
5、tional standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Com
6、mittee.2. Referenced Documents2.1 ASTM Standards:3D823 Practices for Producing Films of Uniform Thicknessof Paint, Coatings and Related Products on Test PanelsD3964 Practice for Selection of Coating Specimens forAppearance MeasurementsD3980 Practice for Interlaboratory Testing of Paint andRelated Ma
7、terials (Withdrawn 1998)4D4039 Test Method for Reflection Haze of High-GlossSurfacesE97 Method of Test for Directional Reflectance Factor,45-Deg 0-Deg, of Opaque Specimens by Broad-BandFilter Reflectometry (Withdrawn 1991)4E430 Test Methods for Measurement of Gloss of High-GlossSurfaces by Abridged
8、Goniophotometry3. Terminology3.1 Definitions:3.1.1 relative luminous reflectance factor, nthe ratio of theluminous flux reflected from a specimen to the luminous fluxreflected from a standard surface under the same geometricconditions. For the purpose of measuring specular gloss, thestandard surface
9、 is polished glass.3.1.2 specular gloss, nthe relative luminous reflectancefactor of a specimen in the mirror direction.4. Summary of Test Method4.1 Measurements are 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:
10、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 for comparingspecimens having 60 gloss values higher than 70.4.1.3 The 85 geometry is used for comparing specimensfor sheen or near-graz
11、ing 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 surface toreflect more light in directions close to the specular than inothers. Measurements by this test method correlate with visualob
12、servations of surface shininess made at roughly the corre-sponding angles.5.1.1 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 inde
13、x of thespecimen, the measured gloss ratings change as the surfacerefractive index changes. In obtaining the visual gloss ratings,however, it is customary to compare the specular reflectancesof two specimens having similar surface refractive indices.1This test method is under the jurisdiction of AST
14、M Committee E12 on Colorand Appearance and is the direct responsibility of Subcommittee E12.03 onGeometry.Current edition approved May 1, 2018. Published May 2018. Originallyapproved in 1939. Last previous edition approved in 2014 as D523 14. DOI:10.1520/D0523-14R18.2The boldface numbers in parenthe
15、ses refer to the list of references at the end ofthis test method.3For 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 standards Document Summary page onthe ASTM web
16、site.4The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles
17、 on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.15.2 Other visual aspects of surface appearance, such asdistinctness of reflected
18、 images, reflection haze, and texture,are frequently involved in the assessment of gloss (1), (6), (7).Test Method E430 includes techniques for the measurement ofboth distinctness-of-image gloss and reflection haze. TestMethod D4039 provides an alternative procedure for measur-ing reflection haze.5.
19、3 Little information 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 instrumental scaling of coated speci-mens that have agreed well with visual scaling (10).5.4 When specimen
20、s differing 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 a light source furnishing an
21、 incident beam, means forlocating the surface of the specimen, and a receptor located toreceive the required pyramid of rays reflected by the specimen.The receptor shall be a photosensitive device responding tovisible radiation.6.2 Geometric ConditionsThe axis of the incident beamshall be at one of
22、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. With a flatpiec
23、e 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 center of this
24、 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 surface in
25、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). The relati
26、ve dimension is thecalculated dimension related to the 60 receptor (=1.0000).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 t
27、he reflected beam).NOTE 1The parallel-beam glossmeters possess the better uniformityof 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 polariza
28、tion ongloss measurement has been reported (11). The magnitude of the polar-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, m
29、easured gloss values are little affected by polarization.6.3 VignettingThere 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 spect
30、rally corrected to yield CIE luminousefficiency with CIE source C. Since specular 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-m
31、easurementmechanism shall give a numerical indication that is propor-tional 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 beas
32、signed a specular gloss value of 100 for each geometry. Thegloss value for glass 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
33、differentfor each geometry. Each 0.001 increment in refractive indexproduces 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
34、 ofincreasing geometry.7.2 Working StandardsCeramic tile, depolished groundopaque glass, emery 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
35、 should bechecked periodically for constancy by comparing with primarystandards.7.3 Store standards 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
36、hold standards atTABLE 1 Angles and Relative Dimensions of Source Image andReceptorsIn Plane ofMeasurementPerpendicular toPlane of Measurement, 2 tan /2RelativeDimension, 2 tan /2RelativeDimensionSource image 0.75 0.0131 0.171 2.5 0.0436 0.568Tolerance 0.25 0.0044 0.057 0.5 0.0087 0.11460 receptor 4
37、.4 0.0768 1.000 11.7 0.2049 2.668Tolerance 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 0.05 0.0009 0.012 0.1 0.0018 0.02385 receptor 4.0 0.0698 0.909 6.0 0.1048 1.365Tolerance 0.3 0.0052 0.068 0.3 0.0052 0.068D523 14 (2018)2the side edges to avoid getting
38、oil from the skin on the standardsurface. Clean the standards in warm water and a 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
39、detergent solution, followedby a final rinse in distilled water. Do not wipe standards. 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
40、Test Specimens8.1 This test method does not cover preparation techniques.Whenever a test for gloss requires the preparation of testspecimens, use the procedures given in Practice D823.NOTE 3To determine the maximum gloss obtainable from a testmaterial, such as a paint or varnish, use Methods B or C
41、of Practice D823.8.2 Select specimens in accordance with Practice D3964.9. Instrument 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,
42、subtract it algebraically from subsequent readings or adjust theinstrument to read 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 con
43、stant. To calibrate, adjust the instru-ment to read correctly the gloss of a highly 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
44、values, check cleanliness and repeat. If theinstrument reading for the second standard 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 manuf
45、acturer.10. Procedure10.1 Position each specimen in turn beneath (or on) theglossmeter. 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
46、 readings ona3by6-in. (75 by150-mm) area of the test specimen. If the range is greater thanFIG. 1 Diagram of Parallel-Beam Glossmeter Showing Apertures and Source Mirror-Image PositionFIG. 2 Diagram of Converging-Beam Glossmeter Showing Apertures and Source Mirror-Image PositionD523 14 (2018)3two gl
47、oss units, take additional readings and calculate the meanafter discarding divergent results as in the section on Test forOutliers of Practice D3980. For larger specimens, take aproportionately greater number of readings. For non-idealsamples, (for example, weathered samples) the parties involvedsha
48、ll determine the acceptable range.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 glossmeter reading. To measure thecorrection, illuminate the specimen perpendicularly and viewat the incident an
49、gle 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 with 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:Geometry, Gloss of Perfect White Diffuser60 2.520 1.2
