We investigate titanium (Ti) and vanadium (V) film growth on amorphous carbon (a-C) and silicon oxide NOD substrates using in situ electrical conductivity measurements and electron microscopy. The aim is to determine the minimum thickness of a continuous layer so that multilayer coatings of fine period can be constructed. We applied a model for thin film metallic conduction to develop a criterion for the onset of electrical continuity. We found that this onset coincides with the minimum in a curve of Rt(2) as a function t, where R is the film resistance and t is the film thickness. For these film/substrate combinations, we found minimum layer thicknesses of between 2.5 and 3 nm are possible. (C) 2004 Elsevier B.V. All rights reserved.