Reflection silver-halide gelatin holograms

Hybrid process of latent image formation in silver halide sensitized gelatin: differential hardening with microvoids

“…Usanov et al [6] ®nd micropores from tenths of a micrometre to several micrometres in size at the sites of the extracted developed silver particles. Also they said the connection of the number and size of microvoid to the degree of swelling of the layer shows that microvoid formation is a natural reaction of the swollen gelatin molecules to dehydration by hydrophilic solvents.…”

“…On the one hand, refractive-index modulation due to a hardness di erential generates part of the di raction e ciency [4,5] and, on the other, the formation of microvoids inside the gelatin results in an increase in the modulation capacity of the latent image [6]. Both models have been studied and analysed from an experimental point of view, with physical evidence in the case of microvoids in re¯ection gratings obtained with the Russian PFG-03 emulsion (precursor of the present Slavich emulsions) by Usanov and Shevtsov [7] and in transmission gratings obtained with the Slavich VR-P plates by Kim et al [8] In this study we aim to review both models of image formation, showing that they are not incompatible and may be combined in order to explain the experimental results.…”