Fast and simple methods for the preparation of porous metal oxide networks are reported here that use readily available cellulose acetate membranes in two procedures that are expected to be of general utility. ZrO2 and TiO2 films were produced of ca. 80 mum thickness, with large pore structures (several hundred nm). The porous structure of the films was shown by TEM and SEM (see Figure, TiO2) to resemble the initial membranes (see also inside front cover).