Prevention of Chemography in Prestained Epoxy Autoradiographs by an Intervening Carbon Film

Evaporation of a carbon layer over toluidine blue stained epoxy sections prior to applying emulsion eliminates or significantly reduces chemography that would otherwise be present in autoradiographs. This simple procedure permits routine proceasing of large numbers of slides without the limitations of the impermeable membranes currently recammended for light microscopic autoradiography following prestaining. The method permits "before and after" microphotography and use of simple staining procedures for sections to be studied autoradiographically.