Designation:D6657−14a´1StandardTestMethodforpHofWetBlue1ThisstandardisissuedunderthefixeddesignationD6657;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ε1NOTE—Paragraph9.1.3wasaddededitoriallyinNovember2014.1.Scope1.1ThistestmethodcoversthedeterminationofthepHofalltypesofwetblueandwetwhite.1.2ForpHofwetwhite,theprocedureisidentical,substi-tutewetwhiteforwetblueinthestandardmethod.1.3ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2D6659PracticeforSamplingandPreparationofWetBlueforPhysicalandChemicalTestsE177PracticeforUseoftheTermsPrecisionandBiasinASTMTestMethodsE691PracticeforConductinganInterlaboratoryStudytoDeterminethePrecisionofaTestMethod3.Terminology3.1DefinitionsofTermSpecifictothisStandard:3.1.1ThepHofasolutionhasbeendefinedasthenegativelogarithmofthehydrogenionactivity.AsolutionofpH7isneutralat24°C.Lowernumbersindicateincreasingacidity;highernumbers,increasingalkalinity.4.SignificanceandUse4.1ThistestmethodisdesignedtomeasurethepHofadistilled-waterextractofwetblue.Thisisconsideredtobeameasureoftheacidityoralkalinityofthewetblue.Excessiveacidityoralkalinitymayhaveadeleteriouseffectontheagingcharacteristicsofwetblueandtheleathermadefromit.4.2Thistestmethodissuitablefordevelopment,control,andserviceevaluationofwetblue.5.Apparatus5.1ElectronicpHMeter,withasuitableelectrode.Themetershallhaveanaccuracyofatleast0.01pHunitandreproducibilityof0.05pHunit.5.2AnalyticalBalance,sensitiveto0.01gorgreater.6.Reagents6.1PurityofWa...
