Some investigations on the distribution of photolytic silver in a silver chloride emulsion have been carried out to get informations on the distribution of electron-traps in the photolysis of the emulsion. The site in silver halide grains where photolytic silver separates preferentially has been regarded as the site where there are efficient traps for photoelectrons. In part (I), the distribution of photolytic silver between the surface and the interior of silver chloride grains has been investigated by a bleaching method. In silver-ion excess emulsion silver separates preferentially on the surface at low level of exposure, indicating that the surface electron-trap is more efficient than the internal one. The internal photolytic silver prevails in chloride excess emulsion probably because of rechlorination. Impregnation of the emulsion with sodium nitrite augments not only the surface photolytic silver at high exposure level but also the internal photolytic silver at low exposure level.