TAPPI T 452 OM-98 brightness of pulp, paper, and paperboard

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1、T452om-98SUGGESTEDMETHOD–1941TENTATIVESTANDARD–1945OFFICIALSTANDARD–1977OFFICIALTESTMETHOD–1983REVISED–1987REVISED–1992REVISED–1998©1998TAPPITheinformationanddatacontainedinthisdocumentwerepreparedbyatechnicalcommitteeoftheAssociation.Thecommitteeandt

2、heAssociationassumenoliabilityorresponsibilityinconnectionwiththeuseofsuchinformationordata,includingbutnotlimitedtoanyliabilityorresponsibilityunderpatent,copyright,ortradesecretlaws.Theuserisresponsiblefordeterminingthatthisdocumentisthemostrecented

3、itionpublished.Brightnessofpulp,paper,andpaperboard(directionalreflectanceat457nm)1.Scope1.1Thismethodisforthedeterminationofthebrightnessofwhite,near-white,andnaturallycoloredpulp,paper,andpaperboard.Brightnessisacommonlyusedindustrytermforthenumeric

4、alvalueofthereflectancefactorofasamplewithrespecttobluelightofspecificspectralandgeometriccharacteristics.Thismethodrequiresaninstrumentemploying45°illuminationand0°viewinggeometrywiththeilluminatingandviewingbeamsadjustedsothattranslucentmaterialsare

5、evaluatedonanarbitrarybutspecificscale.Theconeoflight(seeA.3.2andA.3.5)usedbythismethodiswiderthanthatspecifiedfortheCIEStandard45/0geometry.1.2Thisprocedureisapplicabletoallnaturally-coloredpulps,andpapersandboardmadetherefrom.Themeasurementisnotsuit

6、ableforpaperorpaperboardcontainingaddedcoloringmatter(suchasyelloworgreendyestuff)whichappreciablyabsorbslightinthatpartofthespectrumextendingfromabout400to500nm.Coloredpapersmustbemeasuredeitherspectrophotometricallyorcolorimetricallyinordertoobtainm

7、eaningfulresults(1).1.3Thismethodgives:1.3.1Aprocedureforusingthetestinstrumenttomeasurethedirectionalreflectancefactorat457nmofasampleofpaperorpaperboard(2-5).NOTE1:Theeffectivewavelengthofthespectralbandis457nm.Theshapeofthefunctionisalsoimportantan

8、disdefinedinAppendixA.1.3.2Adescriptionofasystemofpreparing,distributingandusingreflectancestandardsbywhichaninstrumentcanbemaintainedincontinuousagreement,towithinspecifiedtolerances,withamasterinstrument.1.3.3Adetaileddescription(AppendixA)o