Solid State Properties and Photographic Activity of Crystalline Ag₂S- and (Ag, AU)₂S-Specks at the Surface of Silver Halide Crystals

Research sponsored by the “Instituut lOt aanmoediging van het Wetens happelijk Onderloek in Nijverheid en Landbouw” (I.W,O.N,L.) of Belgium

Abstract

In the present paper a model is proposed according to which the photographic activity of silver sulphide specks is explained on behalfof the solid state properties of crystalline cubic silver sulphide, Epitaxial deposit ion of the laller is cia imed to occur at least partly at the (III) faces of AgBr during chemical sensitization, The disorder of the cation sublallice in cubic silver sulphide is con idered to be the physical base of highly efficient electron trapping, whereas the high electronic conductivity is rcsponsible for its catalytic activity towards developmcnt (fog). Excess silvcr in non stoichiometric cubic silver sulphide plays a very important role in its photographic behaviour inclUding development kinetics, The model provides a coherent explanation of a great number of experimental facts including the effects introduced by gold ions during sulphur sensitization.

Notes

Research sponsored by the “Instituut lOt aanmoediging van het Wetens happelijk Onderloek in Nijverheid en Landbouw” (I.W,O.N,L.) of Belgium