Sensitization of Formate Ions Doped at Different Depths of Silver Bromide Microcrystals

摘要

In the emulsifying process of AgBr microcrystals in the double-jet apparatus controlled by a microcomputer, a certain amount of formate salt was added at a specific time and pAg to a reactor to prepare a series of cubic AgBr emulsions in which formate ions were doped at different depths of AgBr microcrystals. The sensitometric results from these emulsions showed: 1) that the sensitivities of formate-doped emulsions, relative to that of the undoped emulsion as the controlled one, were remarkably increased; 2) that the closer to the surface of grains the doped formate was, the greater the sensitivity was; 3) that a cooperative sensitization by formate dopant, S+Au and dye was observed without any significant increase in fog level; 4) that the maximal sensitivity gain (S{sub}(max)/S{sub}0) of undye-sensitized emulsions was greater than those of dye-sensitized ones.