The effect of thermal and anion-impurity factors on the electro-field coalescence of silver atoms in its halide microcrystals
Purpose. The discovery, in 1970, of the “electrotopographic” effect on halogen-silver photographic materials contributed to the appearance of the photograph of a new kind, later called “electro-field photography”. The development of the physical and mathematical model of the kinetics of the electro-field coalescence of silver atoms in its halide microcrystals in 2014 allowed substantiating the previously existing theoretical and applied aspects of the process and predicting the conditions for controlling it. This paper is dedicated to the experimental verification of the influence of the cryothermic and anion-impurity factors on this process in the form of iodine ions, replacing bromine ions in silver halide microcrystals. Methods and methodology. The study of the thermal influence was carried out on commercially available films for radiographs “Agfa” and “Retina”, as well as on specially made photographic films with AgBr microcrystals with a decreased temperature compared to the standard 298 K. The study of the effect of anion-impurity factors was tested on specially manufactured photographic films with mixed AgHal microcrystals with different amounts of iodine ions and bromine ions. Results and conclusions. Using both commercially produced films for radiographs and specially made films showed the gain in the coalescence process of silver atoms affected by the electric field with a decrease in temperature from 298 to 292 K, or a 5% substitution of bromine ions to iodine ions in AgBr crystals at 298 K. A certain correlation was found between the optical density of the electro-field images and their dimensions with voltage impulses of varying polarity. Regardless of the thermal or anion-impurity factor, the parameter X appears to be smaller than c with the impulse of the same polarity, and vice versa with the impulse of the opposite polarity. An exception to this rule was the “Retina” film. This can be due to its exposure to the electric field through the base of the “Agfa” film. The effects X and % for the “EPhM-45” film, while retaining the described correlation, have opposing qualities, which is obviously due to the presence of two phases of microcrystals in a photo-emulsion consisting of a pure AgI and AgHal with a mixed composition of halogens.