High amplification cobalt imaging system

Abstract

A novel high gain photothermographic imaging process is described. The essential components consist of a Co^III amine, a redox transfer lig- and L and a light-sensitive element capable of producing centers of Co^II. On exposure, a reducing agent is produced, commonly via a quinone which photogenerates a hydroquinone. On heating, the hydroquinone reduces Co^III amine to produce Co^II. The ligand then complexes this Co^II to form Co^II L_n, which, in turn reduces more Co^III amine. The resulting reaction produces a metallized dye, Co^IIIL_n, amine and more Co^II, which in the presence of excess L continues the cycle, giving photographically useful amplification. The system is capable of speed several thousand times that of an efficient one-quantum process.