A self-contained silver halide diffusion transfer imaging sheet is provided which contains three layers on a substrate. The first layer is a silver halide emulsion formed in a non-ionic material. The intermediate layer is a water barrier. The third layer is a nucleating region which contains collodial silver. A developer, base and silver transport agent can also be located in these layers. For example, the base and silver transport agent can be located in the nucleating layer, with the developer located in the emulsion layer. After the emulsion is exposed to actinic radiation, a non-aqueous activating medium is supplied which initiates the development and diffusion transfer processes. The final result is a positive image in the nucleating layer.