Abstract: A method is described for reducing the defect density in a crystalline film grown on a substrate with which it has a substantial misfit. The principle of the method is to grow the film, not directly from the substrate, but from a layer of small islands previously deposited onto the substrate. The technique has been fully investigated for the growth of Ag (and then Au) films on NaCl, a substantial improvement in the quality of the overgrown film being obtained when an intermediate layer of Ni islands is deposited on the NaCl prior to the deposition of the Ag.