1、Designation:D396410(Reapproved 2015)Standard 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
2、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 practice provides a guide to selection of specimensfor appearance measurement by reflected light as well as adiscussio
3、n of factors 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 andinstrumenta
4、l measurements.NOTE1This 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 safet
5、y 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 Definitio
6、ns: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 manner i
7、n 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 thematerial of i
8、nterest.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 dictated by thes
9、ize 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 istherefore more
10、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 specimenaveraging.5.3 OpacityFor d
11、etermination 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 reflection from the backor sec
12、ond 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 opticalcontact with it.5.3.
13、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 techniques that follow.1Thi
14、s 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 July 1,2015.Published July 2015.Originally approvedin 1980.Last previous edition ap
15、proved in 2010 as D3964 10.DOI:10.1520/D3964-10R15.2For 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 page onthe ASTM website.Copyright ASTM
16、International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 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 material 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 bein
