A novel dispersion imaging material comprising a substrate, a sublayer thereon comprising at least 70% by weight of a member selected from palladium, gold, germanium and combinations thereof and having a thickness of 5 A to 200 A, and a main imaging layer on said sublayer comprising at least 50% by weight of tin, and optionally as the outermost layer a protective layer comprising an organic polymer. The sublayer modifies the layer structure of the tin-based main imaging layer. The imaging material has a high safety in respect of toxicity as well as an excellent gradation and a high sensitivity. The imaging material can form thereon an image by a dry process even in a light room without the conventional development and fixation steps.