Designation:D2019–97(Reapproved2007)AnAmericanNationalStandardStandardTestMethodforDirtinPaperandPaperboard1ThisstandardisissuedunderthefixeddesignationD2019;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethod(1,2,3)2isintendedforthenumericalestimationofdirtinpaperorpaperboardintermsofequivalentblackarea.Thistestmethodissatisfactoryonlyfortheestimationofvisualdirtinessanditmaybeentirelyinadequatewhenthegrittinessorothernonvisualeffectsofdirtareofimportance.2.ReferencedDocuments2.1ASTMStandards:3D585PracticeforSamplingandAcceptingaSingleLotofPaper,Paperboard,Fiberboard,andRelatedProductD985TestMethodforBrightnessofPulp,Paper,andPaperboard(DirectionalReflectanceat457nm)D1968TerminologyRelatingtoPaperandPaperProducts3.Terminology3.1Definitions—DefinitionsshallbeinaccordancewithTerminologyD1968andtheDictionaryofPaper.44.SummaryofTestMethod4.1Adirtspeckiscomparedwithblackspotsonastandard“dirtchart,”andtheareaoftheblackspotthatgivesthesamevisualimpressionasthedirtspeckisrecorded.Thesumofallsuchareas(knownasequivalentblackareas,ore.b.a.)thatare0.04mm2orgreaterisdividedbythetotalareaofthepaperinspected.Theresult,expressedinpartspermillion,isusedasameasureofthedirtinpaperorpaperboard.5.SignificanceandUse5.1Whiledirtinpaperisusuallythatfoundonthesurfaceofthesheet,someparticlesembeddedinthebodyofthesheetmaybereadilydiscernible,especiallyinpapersthataretransparentortranslucent.Therefore,asaproperty,dirtcontentmayaffectboththeutilityandcompositionofthesheet.Theamountofdirtpresentinasheetofpaperisofimportanceinpracticallyeverytypeofpaper,butespeciallysointhehigher-qualityproducts.Forexample,bondandfinewritingpapersaresubjecttocloseinspectionfordirtcontent,andtheamountofdirtpresentinthesheetisoneofthefactorsinclassifyingthemintodifferentgrades.5.2Th...
