The magneticdomaincontrastinwide-field Kerrmicroscopyonbulkspecimenscanbesubstantially
distortedbynon-linear, field-dependent Faradayrotationsintheobjectivelensthatarecausedbystray-
field componentsemergingfromthespecimen.TheseFaradaycontributions,whichweredetectedby
Kerr-magnetometryongrain-orientediron–silicon steelsamples,arethoroughlyelaboratedandchar-
acterized. Theyexpressthemselvesasa field-dependent gray-scaleoffsettothedomaincontrastandin
highly distortedsurfacemagnetizationcurvesifopticallymeasuredinawide field Kerrmicroscope.An
experimentalmethodtoavoidsuchdistortionsissuggested.Inthecourseofthesestudies,alow-per-
meability partinthesurfacemagnetizationloopofslightlymisoriented(110)-surfacesiniron–silicon
sheets wasdiscoveredthatisattributedtodemagnetizationeffectsindirectionperpendiculartothe
sheet surface.