Method of detecting pinholes in a magnetic recording medium

摘要

A magnetic recording medium comprising a plastic film support having a magnetic recording layer on one side is provided with a backing layer containing: (1) a white and/or light colored powder; (2) carbon black and/or graphite; and (3) a polymeric binder. The backing layer transmits more than 3% of white light at a thickness of 2 microns and has a surface electrical resistance of less than 1010 OMEGA /cm. Pinholes and drop-out are easily detected in forming such a magnetic recording medium.