ASTM_D_2457_-_13.pdf

Designation:D245713Standard Test Method forSpecular Gloss of Plastic Films and Solid Plastics1This standard is issued under the fixed designation D2457;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 parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 This test method describes procedures for the measure-ment of gloss of plastic films and solid plastics,both opaqueand transparent.It contains four separate gloss angles(Note 1):1.1.1 60-deg,recommended for intermediate-gloss films,1.1.2 20-deg,recommended for high-gloss films,1.1.3 45-deg,recommended for intermediate and low-glossfilms,1.1.4 85-deg,recommended for intermediate and low glossfilms,and1.1.5 75-deg,recommended for plastic siding and soffit.NOTE1The 85-deg,75-deg,60-deg,and 20-deg apparatus andmethod of measurement duplicate those in Test Method D523 and D3679;those for the 45 procedure are similarly taken from Test Method C346.1.2 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 and health practices and determine the applica-bility of regulatory limitations prior to use.NOTE2There is no known ISO equivalent to this standard.2.Referenced Documents2.1 ASTM Standards:2C346 Test Method for 45-deg Specular Gloss of CeramicMaterialsD523 Test Method for Specular GlossD3679 Specification for Rigid Poly(Vinyl Chloride)(PVC)SidingE284 Terminology of AppearanceE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1347 Test Method for Color and Color-Difference Mea-surement by Tristimulus ColorimetryE1349 Test Method for Reflectance Factor and Color bySpectrophotometry Using Bidirectional(45:0 or 0:45)Geometry3.Terminology3.1 DefinitionsFor definitions of terms used in this testmethod,see Terminology E284.4.Significance and Use4.1 Specular gloss is used primarily as a measure of theshiny appearance of films and surfaces.Precise comparisons ofgloss values are meaningful only when they refer to the samemeasurement procedure and same general type of material.Inparticular,gloss values for transparent films should not becompared with those for opaque films,and vice versa.Gloss isa complex attribute of a surface which cannot be completelymeasured by any single number.4.2 Specular gloss usually varies with surface smoothnessand flatness.It is sometimes used for comparative measure-ments of these surface properties.5.Apparatus5.1 Instrumental ComponentsEach apparatus(Note 3)shall consist of an incandescent light source furnishing anincident beam,means for locating the surface of the specimen,and a receptor located to receive the required pyramid of raysreflected by the specimen.The receptor shall be a photosensi-tive device responding to visible radiation.NOTE3The 75-,60-,and 20-deg procedures require apparatusidentical to that specified in Test Method D523.The 45 procedurerequires apparatus like that specified in Test Method C346.5.2 Geometric ConditionsThe axis of the incident beamshall be 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.With a flatpiece of polished black glass or other front-surface mirror inspecimen position,an image of the source shall be formed atthe center of the receptor field stop(receptor window).Thelength of the illuminated area of the specimen shall be equal tonot more than one third of the distance from the center of thisarea to the receptor field stop.The angular dimensions andtolerances of the geometry of the source and receptor shall beas indicated in Table 1.The angular dimensions of the receptorfield stop are measured from the center of the test surface.The1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.40 on Optical Properties.Current edition approved April 1,2013.Published April 2013.Originallyapproved in 1965.Last previous edition approved in 2008 as D2457 081.DOI:10.1520/D2457-13.2For 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 angular dimensions of the source field stop are mostly easilymeasured by the specimen-to-window angular size of themirror image of the source formed in the receptor field stop.(See Fig.1 for a generalized illustration of the dimensions.)The tolerances are chosen so that errors