Details:
Summary:
In order to elucidate the photohardening mechanism in the dichromate-gelatin process, the authors investigated the photochemical reaction between dichromate and several kinds of organic compounds, the structures of which included -OH -CO, -CHO, -COOH, or -NH2 the same groups as those included in the gelatin molecule. Mixtures were prepared from dichromate and each of the organic compounds, and exposed to light for a long time. Colored precipitates were formed in the solutions. The precipitates were separated by centrifuging and then dried. Their physico-chemical properties were measured by electric, magnetic, optical and thermal methods. The compounds seem to be complex compounds consisting of reduced chromium ion and some of the groups which were initially added to dichromate solution.