DEGRADATION OF GELATIN IN HISTORICAL PHOTOGRAPHS

In order to study age related changes in photographic gelatin we analy sed black-and-white roll film before and after accelerated ageing and samples of naturally aged glass plate negatives. Two-dimensional gel e lectrophoresis (2D-PAGE) was used to separate collagen chains in the g elatin by isoelectric point (pI) and molecular weight. The results sho w that the alpha-chain break down into smaller fragments on ageing. Am ino acid analysis was performed to examine the oxidative deterioration of gelatin. It shows that the amount of lysine decreases with age.