Designation:D985–97(Reapproved2007)AnAmericanNationalStandardStandardTestMethodforBrightnessofPulp,Paper,andPaperboard(DirectionalReflectanceat457nm)1ThisstandardisissuedunderthefixeddesignationD985;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethoddeterminesthebrightnessofwhite,near-white,andnaturallycoloredpulp,paper,andpaperboard.Brightnessisacommonlyusedindustrytermforthenumericalvalueofthereflectancefactorofasample,withrespecttobluelightofspecificspectralandgeometriccharacteristics.Thistestmethodrequiresaninstrumentemploying45°illuminationand0°viewinggeometry,withtheilluminatingandviewingbeamsadjustedsothattranslucentmaterialsareevaluatedonanarbitrarybutspecificscale(1-4).21.2Thistestmethodisapplicabletoallnaturally-coloredpulps,andpapersandboardmadefrompulps.Themeasure-mentisnotsuitableforpaperandpaperboardcontainingaddedcoloringmatter(suchasyelloworgreendyestuff)whichappreciablyabsorbslightinthatpartofthespectrumextendingfromabout400to500nm.Coloredpapersmustbemeasuredspectrophotometricallyorcolorimetricallyinordertoobtainmeaningfulresults(TAPPIT442,T524,andT527).Thistestmethodis,however,suitableforpulpsorpaperswhichcontainoptical(fluorescent)brighteningagents.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:3D585PracticeforSamplingandAcceptingaSingleLotofPaper,Paperboard,Fiberboard,andRelatedProductD1968TerminologyRelatingtoPaperandPaperProducts2.2TAPPIStandards:4T218ForminghandsheetsforreflectancetestsofpulpT442Spectralreflectancefactor,transmittanceandcolorofpaperandpulp(Polychromaticillumination)T...
