Effects of N0₂ and S0₂ on the Degradation of Photographic Gelatin

Paper presented at the Royal Photographic Society Conference on Photographic Gelatin, Cambridge, 15-19 September 1997.

Abstract

The degradation of photographic gelatin exposed to a mixture of two pollutant j gases, NO₂ and SO₂, was investigated by swelling measurements and steric I exclusion high performance liquid chromatography. The study, performed on one unhardened gelatin and two hardened gelatins, showed that all three are sensitive to pollutants. Two major effects were noted: the first was an increasing of the swelling of the gelatin films in deinineralized water and the second effect was a change in the steric exclusion chromatographic profile, corresponding to a shift to smaller molecular weights. Both these phenomena indicate that the pollutant gases induce hydrolysis of the gelatin macromolecules. Nevertheless, for the same exposure, the hardened gelatins are shoum to be less degraded than the unhardened one. Thus, even if it does not protect the photographic gelatin totally from attack by the pollutant gases, hardening slozos down its deterioration.

Notes

Paper presented at the Royal Photographic Society Conference on Photographic Gelatin, Cambridge, 15-19 September 1997.