Designation:E1951−14StandardGuideforCalibratingReticlesandLightMicroscopeMagnifications1ThisstandardisissuedunderthefixeddesignationE1951;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thisguidecoversmethodsforcalculatingandcalibrat-ingmicroscopemagnifications,photographicmagnifications,videomonitormagnifications,grainsizecomparisonreticles,andothermeasuringreticles.Reflectedlightmicroscopesareusedtocharacterizematerialmicrostructures.Manymaterialsengineeringdecisionsmaybebasedonqualitativeandquan-titativeanalysesofamicrostructure.Itisessentialthatmicro-scopemagnificationsandreticledimensionsbeaccurate.1.2Thecalibrationusingthesemethodsisonlyaspreciseasthemeasuringdevicesused.ItisrecommendedthatthestagemicrometerorscaleusedinthecalibrationshouldbetraceabletotheNationalInstituteofStandardsandTechnology(NIST)orasimilarorganization.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2E7TerminologyRelatingtoMetallographyE112TestMethodsforDeterminingAverageGrainSize3.Terminology3.1Definitions—AlltermsusedinthisguidearedefinedinTerminologyE7.4.SignificanceandUse4.1Thesemethodscanbeusedtodeterminemagnificationsasviewedthroughtheeyepiecesoflightmicroscopes.4.2Thesemethodscanbeusedtocalibratemicroscopemagnificationsforphotography,videosystems,andprojectionstations.4.3Reticlesmaybecalibratedasindependentarticlesandascomponentsofamicroscopesystem.5.Procedures5.1NominalMagnificationCalculations:5.1.1Acalculatedmagnification,usingthemanufacturer’ssuppliedratings,isonlyanapproximationofthetruemagnification,sinceindividualopticalcompon...
