The Light Sensitive Behaviour of Palladium Doped Ferrioxalate Salts

Paper presented at a symposium on “Non-Silver Photographic Processes” organized by the Science Committee of the Royal Photographic Society, 30 September—3 October, 1969 in Oxford.

Abstract

A series of experiments made on film and papers coated with a mixture of water soluble ferrioxalate salts and palladous chloride is described. The experiments were made with the object of determining if the behaviour of these coatings could be explained in terms of the theory of operation used to describe the palladiotype system. The results obtained using these coated papers and films (which contained considerably less palladium than that used in the palladiotype system) were not all in agreement with the behaviour predicted on the basis of the old theory. Therefore, an alternative model has been put forward and this model does explain the results obtained. In this model it is proposed that exposure to light produces electrons in the conduction band of palladium doped potassium ferrioxalate crystallites present in the coated material. These electrons are trapped by the palladium ions to produce a palladium latent image and are also trapped by the ferric ions to produce a ferrous image or latent image. In the system examined the weak images produced by the light are physically developed in an electroless plating bath using such metals as nickel or copper as the plating material.

Notes

Paper presented at a symposium on “Non-Silver Photographic Processes” organized by the Science Committee of the Royal Photographic Society, 30 September—3 October, 1969 in Oxford.