1、Designation: D3964 10Standard Practice forSelection of Coating Specimens for AppearanceMeasurements1This standard is issued under the fixed designation D3964; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisio
2、n. 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 practice provides a guide to selection of specimensfor appearance measurement by reflected light as well as adiscussion of fa
3、ctors to be considered in their preparation formeasurement. Standardized selection and presentation proce-dures will assist in achieving agreement between evaluationscarried out in different laboratories as well as helping toachieve better correlations between visual evaluations andinstrumental meas
4、urements.NOTE 1This standard is not a practice for preparation of test panels ofcoatings; see Practices D823.1.2 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-priate safety
5、 and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D823 Practices for Producing Films of Uniform Thicknessof Paint, Varnish, and Related Products on Test PanelsE284 Terminology of Appearance3. Terminology3.1 Defini
6、tions:3.1.1 For definitions of terms used in this practice, refer toTerminology E284.4. Significance and Use4.1 Many of the specimens that are regularly submitted tomeasurement depart in some degree from the ideal require-ments. For this reason instrumental readings are affectedimportantly by the ma
7、nner in which specimens are selected andpresented for measurement. Reproducible measurements arefacilitated by standardization and control of test conditions.5. General Requirements5.1 SelectionIn making appearance measurements it isimportant that the specimens selected be representative of themater
8、ial of interest. Once selected, the specimens must becarefully examined to determine if they are suitable formeasurement, and if not, they must be cleaned or otherwiseprepared. Careful attention to these factors is necessary if themeasurements are to be valid.5.2 Specimen SizeThe minimum size is dic
9、tated by thesize of the specimen port of the instrument to be used formeasurement. When an instrument provides a choice of speci-men port sizes, use the largest port that can be completelycovered by the specimen. A large measured area helps tominimize the effect of any small area nonuniformity and i
10、stherefore more likely to provide results that agree with theinvoluntary averaging that takes place when specimens areobserved visually. In addition, a large specimen also permitsthe operator to make measurements on several areas of thespecimen when desired, thereby providing further specimenaveragi
11、ng.5.3 OpacityFor determination of gloss or color, an opaquespecimen shall be selected whenever possible. When thespecimen is translucent or transparent, the following practicesshall be implemented:5.3.1 For Gloss EvaluationThe specimen shall preferablybe sufficiently thick that a secondary reflecti
12、on from the backor second surface of the specimen cannot enter the receptoroptics of the glossmeter. When thin transparent specimensmust be measured, adopt one of the following procedures:5.3.1.1 Back the specimen with a light-absorbing materialof the same refractive index as the specimen, and in op
13、ticalcontact with it.5.3.1.2 Use an agreed-upon specimen thickness, includingcoating and substrate, and place a black backing behind thespecimen.5.3.2 For Color EvaluationThe choice of backing of evenslightly translucent specimens will affect their measurement.Use the most applicable of the backing
14、techniques that follow.1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.26 on Optical Properties.Current edition approved June 1, 2010. Published June 2010. Originallyapproved
15、in 1980. Last previous edition approved in 2004 as D3964 04. DOI:10.1520/D3964-10.2For 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 standards Document Summary pag
16、e onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.In each case it is essential that the backing material and colorbe reproducible, stable, and durable for reliable results.5.3.2.1 Back the specimen with the same ma
17、terial withwhich it will be backed in its intended use.5.3.2.2 Back the specimen with identical or similar material.5.3.2.3 Back the specimen with a neutral material whoseluminous reflectance is essentially the same as that of thespecimen being evaluated.5.3.2.4 Back the specimen with a black surfac
18、e such as apainted panel or black glass.5.3.2.5 Back the specimen with a white backing of knownreflectance.6. Physical Properties6.1 The specimen shall preferably be rigid and have a planesurface. Specimens of thin, flexible material that can bulge orsag when presented to an instrument require speci
19、al holdingequipment. When the specimen is moderately flexible, a planesurface may be achieved by pressing the specimen against theinstrument with a flat, rigid object. The pressing techniquemust be reproducible. A vacuum plate or specially designedclamping device has proven satisfactory in some appl
20、ications.Note that specimens coated on thin plastic film or paper maytrap air between the specimen and the holder (vacuum plate orclamping device) causing the specimen to billow (blister)resulting in erroneous readings.6.2 Surface TextureSome coatings have pronounced sur-face texture, making it desi
21、rable to rotate a specimen in its ownplane. Those with marked directionality, usually due to theproduction process, will have different values when measuredin different directions. Good practice dictates that measure-ments be made with the plane of measurement of the instru-ment both parallel to as
22、well as perpendicular to the processdirection.7. Cleaning of Specimens7.1 The specimen shall be clean. There should be no dirt,dust, oil or foreign material on the surface that will affect theinstrumental evaluation of the specimen. If the specimenappears to require cleaning, the procedure should be
23、 agreedupon and it should be carried out with care. Any cleaning of alow-gloss or fragile surface may scratch or polish the surfaceand thus change the appearance of the specimen and render ituseless for measurement. A high-gloss specimen may usuallybe washed with clear water and blotted with untreat
24、ed lenstissue or paper towel. If the specimen is durable, a mildnonfluorescent, nonionic detergent that does not leave a filmcan be used with a soft cloth or bristle brush. If the specimenis durable and has an oily or stubborn contamination thatshould be removed, reagent grade isopropyl alcohol may
25、beused. Follow all cleaning techniques with a warm water rinseand drying by blotting, using untreated lint-free paper towel.NOTE 2Ceramic or porcelain-enameled instrument calibration stan-dards require periodic cleaning and the above procedures can generally beused safely. Care should be taken to en
26、sure that no water or other cleaningagent enters the edges of these standards.8. Handling Specimens8.1 Handle specimens by their edges. Do not allow objectsto contact the front surface of the specimen. When placing thespecimen on the instrument, avoid sliding it across the speci-men port.9. Report9.
27、1 When the specimens submitted for appearance measure-ments depart from the ideal requirements, report the following:9.1.1 Their condition (Section 6),9.1.2 Method of cleaning (Section 7),9.1.3 Method of backing (5.3.1, 5.3.2, and 6.1), and9.1.4 Indicate direction of specimen submitted for measure-m
28、ent or averaging of data, or both, when required by direc-tionality (6.2).10. Keywords10.1 appearance; color; gloss; measurement; opacity;uniformityASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users
29、of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every fi
30、ve years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical
31、committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, P
32、A 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D3964 102
