Effects of several inhibitors on contrast of physical developed silver in one-sheet DTR (diffusion transfer reverse) system were studied in this article. In this DTR system, the general measured reflection density could not be directly adopted because it was a comprehensive value of physically developed silver on the surface and chemically developed silver in the emulsion. For this reason, a one-dimensional CCD instrument was applied to monitor the reflected light intensity during development. The light intensity was accepted to describe the amount of physically developed silver of each exposed step on plate, then the contrast coefficient could be calculated out from the curve of light intensity versus logE. It was found that some inhibitors could improve the contrast of physically developed silver image accompanied with an improvement on sensitivity in this one-sheet DTR system.

A thiol compound with a long hydrocarbon chain was introduced into the developing solution for a silver chloride DTR printing plate. It was found that the hydrophobicity of physically developed silver area could be greatly improved. The higher the silver density and thiol concentration were, the greater the hydrophobicity of the silver surface was. Raman and XPS study revealed that hydrophobization was caused by adsorption of the thiol compound on physically developed silver particles on the plate.