A common standard configuration used in polarized-light microscopy with the substage polarizing filter (polarizer) permitting plane polarized light with its electric vector in an east-west direction and the above-stage polarizing filter (analyzer) permitting plane polarized light with its electric vector in a north-south direction. Under these conditions all light is absorbed by the two polars. Introduction of any anisotropic transparent material into the light path repolarizes light between the polars so as to generate interference colors and other effects visible in the microscope ocular.