Designation:F1252−10StandardTestMethodforMeasuringOpticalReflectivityofTransparentMaterials1ThisstandardisissuedunderthefixeddesignationF1252;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversaprocedureformeasuringthereflectivityoftransparentmaterials,hereafterknownasspeci-mens.Theresultsarerepeatablewithoutspecifyingaparticularbrandnameofinstrumentation.1.2Thistestmethodappliestosubstantiallyflatparts.Errorsinmeasurementcanoccurifthepartsbeingmeasuredarenotsubstantiallyflat.1.3ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.Terminology2.1Definitions:2.1.1angleofincidence(Θi)—intheplaneofthelightsource,specimen,andphotometer,theangleofincidenceistheanglebetweentheincidentlightrayandthenormaltothesurface(seeFig.1).2.1.2angleofreflection(Θr)—intheplaneofthelightsource,specimen,andphotometer,theangleofreflectionistheanglebetweenthereflectedlightrayandthenormaltothesurface(seeFig.1).2.1.3lightsource—unlessotherwisespecified,theNationalInstituteofStandardsandTechnology(NIST)diffusednonpo-larizedStandardIlluminanceAorClightsourceshallbeused.Thelightsourcesizewillbesuchthattherewillbesufficientoverlapofthefrontandrearimagesonthespecimentooverfillthemeasurementfieldsizeofthephotometer.ThisoverlapisillustratedinFig.2.(Asangleofincidenceandspecimenthicknessincrease,thetwoimageswilldiverge.)Thelightsourceusedshouldbespecifiedandreportedaspartofthetestresults.2.1.4measurementfieldsize—theangularextent,indegrees,ofthemeasurementapertureofthephot...
