ASTM_D_4039_-_09_2015.pdf

Designation:D403909(Reapproved 2015)Standard Test Method forReflection Haze of High-Gloss Surfaces1This standard is issued under the fixed designation D4039;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.Scope1.1 This test method describes a procedure for using twospecular gloss measurements to obtain a haze index forhigh-gloss nonmetallic specimens(1-4).2It is particularlyuseful for evaluating the haze in clear finishes on nonglossysubstrates,and the haze in reflected images produced by thesurfaces of opaque glossy pigmented finishes.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.2.Referenced Documents2.1 ASTM Standards:3D523 Test Method for Specular GlossD823 Practices for Producing Films of Uniform Thicknessof Paint,Varnish,and Related Products on Test PanelsD3964 Practice for Selection of Coating Specimens forAppearance MeasurementsE284 Terminology of AppearanceE430 Test Methods for Measurement of Gloss of High-GlossSurfaces by Abridged Goniophotometry3.Terminology3.1 Definitions:3.1.1 specular gloss,nratio of flux reflected in speculardirection to incident flux for a specified angle of incidence andsource and receptor angular apertures.3.1.2 haze,nin reflectionscattering of light at the glossysurface of a specimen responsible for the apparent reduction ofcontrast of objects viewed by reflection at the surface.3.2 Definitions of Terms Specific to This Standard:3.2.1 60 specular gloss G60,nspecular gloss measuredwith the 60 geometry specified in Test Method D523.3.2.2 20 specular gloss G20,nspecular gloss measuredwith the 20 geometry specified in Test Method D523.3.2.3 haze index,H,na measure of reflection haze,whereH=G60 G20.3.3 Appearance terms used in this standard are defined inTerminology E284.4.Summary of Test Method4.1 Measurements of 60 and 20 specular gloss are madeon a specimen.The haze index is computed as the differencebetween the two measurements.4.2 This test method is applicable to nonmetallic specimenshaving a 60 specular gloss value greater than 70 in accordancewith Test Method D523.4.3 Both 60 and 20 specular gloss depend upon therefractive index of the material being measured.Because 20gloss changes much more rapidly with index than 60 gloss,the reflection haze value of a specimen also depends on theindex of refraction of the material.To establish a correction forthe effect of refractive index would require its measurement foreach material,which is inconvenient.Comparisons of reflec-tion haze evaluated by this test method are therefore limited tospecimens of essentially the same refractive index.5.Significance and Use5.1 Measured gloss values of specimens depend on theangle of illumination,refractive index of the material,and thegeometric distribution of the reflected light.5.2 Haze is produced by irregularities in the reflectingsurface that affect the distribution of flux reflected around thespecular angle.The procedures specified in Test Method D523are not designed to measure reflected-flux scattering character-istics of high-gloss finishes,particularly where specimenshaving different surface refractive indexes are being compared.5.3 In this test method,values for reflection haze areobtained from two measurements of specular gloss,one madewith a large receptor aperture and the other made with a smallreceptor aperture.The geometric conditions have been chosento permit the use of glossmeters that provide 60 specular gloss1This 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 Nov.1,2015.Published November 2015.Originallyapproved in 1981.Last previous edition approved in 2009 as D4039 09.DOI:10.1520/D4039-09R15.2Boldface numbers in parentheses refer to the list of references at the end of thistest 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 website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 measurements(large receptor aperture)and 20 specular glossmeasurements(small receptor aperture)as specified in TestMethod D523.5.4 An additional method for the measurement of reflectionhaze is given in Test Method E430.6.Apparatus6.1 Glossmeter(s),capable of measuring 60 and 20 specu-lar gloss in accordance with the specifications given in TestMethod D5