A magnetic tape (1) characterized by having a backcoating layer (5) which comprises a binder and fine particles having been dispersed in the binder and being capable of irreversibly changing in color on oxidation reaction, and has a sufficient number of microvoids of sufficient size to supply sufficient...http://www.google.com.au/patents/US7255908?utm_source=gb-gplus-sharePatent US7255908 - Magnetic tape
