Activating Effect of Na2S203 on the Developing of Galvanic Cell Type Electrophotography

The present paper is concerned with a e!ectrophotogr-aph wbich is pteve. loped in NiCla solution through the cell reaction of (ZnO/NiCl2/Al). The maximum image density was obtained from the neutral electrolyte solution containing O.7 mol/1 NiCl, 0.7. -2, 8 mol/1 NH4Cl and O. Ol mol/l Na2S2O2. The deposition efficiency of nickel was low in acidic solutions. Nickel was deposited from its ammine complex ion which was stable at pH higher than 6. Thiosulfate ion was effective to accelerate the nickel deposition below the cortcentration of 10g mol/1, A direct electron transfer from Al electrode to Ni2 seemed to occur rapidly in the solution containing thiosulfate ion above 10-8 mol/1. The potential between the alminum plate 2-iffbr Tla-xef and a calomel electrode was influencedh. She Cl-m. concept r4Sign Schqrgsult fiihY rm66 ascribed to the increase Qf thg act3yllty of AIS: i ign, The potential mentioned above bec stable in the solution with lew free NiN concentration.