A simple diffusion method for the distribution of ultrafine silver bromide grains in precoated gelatin and customized polymeric films for holographic recording has been developed. The method involves two steps: immersion of the pre-formed film in a solution of a silver salt, followed by agitation of the film in a solution of a bromide salt containing sensitizing dye. Repetition of the operation on the same film with different sensitizing dyes in the bromide bath enables the production of film with a panchromatic response. Transmission electron microscopy reveals a grain structure very suitable for use in holography. A reflection hologram made by this method has a similar brightness under the same exposure and processing conditions to one made from a proprietary hologram recording material currently available.