The adsorption of iodide on silver and the effect of the adsorption on the reduction of hydrogen peroxide were studied by use of ESCA in conjunction with electrochemistry. On the basis of the observation that 0.25 monolayer of adsorbed iodide or less is enough to create a large energy barrier for the reduction of H2O2 on silver, a possible explanation for the role of iodide as a catalyst poison in improving image stability is given. Competitive adsorption experiments with iodide and thiosulfate show that under processing conditions, enough iodide is coadsorbed with sulfide, from the decomposition of S2O2/3- to produce a silver surface at which the reduction of peroxide required substantially more energy than a clean silver surface.Ag2S was oxidized by H2O2 to Ag2SO4: however, AgI was not oxidized under similar conditions. -- AATA