NOVELTY - A permeable film has a porous support, at least 1 x 10-10 mol/m2.s.Pa hydrogen permeation rate and at least one from: (1) selective permeation of hydrogen from steam; (2) at most 1 x 10-2 g/h per cm2 loss rate of ethylene glycol through a film at 85 degreesC; and (2) at most 5 x 10-3 equivs. per 1 cm2 film of acid in 5 % ammonium adipate ethylene glycol solution sealed at 85 degreesC for 2 days.    USE - For electrolytic condensers (claimed) and fuel cells, and for separating at least one type of mol. from a gaseous or liquid mixture comprising at least two types of mol. (claimed method). The film is useful for gas separation or permeation in the presence of highly polar vapors, such as water, ethylene glycol, approximately gamma-butyrolactone and ammonia.    ADVANTAGE - The film has high permeability for hydrogen and poor permeability for steam, gaseous ethylene glycol and gaseous ammonia, and has excellent resistance to chemicals and heat, being usable at 150 degreesC or above. In fuel cells, hydrogen is efficiently separated from water, carbon monoxide and carbon dioxide. In condensers, the generated hydrogen is transmitted through the film to the outside, so that there is no pressure increase nor resulting damage or rupture of the vessel, thus preventing large losses of electrolytic solution.    DETAILED DESCRIPTION - A permeable film has a porous support, has at least 1 x 10-10 mol/m2.s.Pa hydrogen permeation rate, and has at least one property from: (1) hydrogen is selectively permeated from steam; (2) when a test tube containing ethylene glycol is sealed with the film and placed in an oven at 85 degreesC, the measured loss rate is at most 1 x 10-2 g/h per 1 cm2 film; and (3) when a test tube containing 5 % ammonium adipate ethylene glycol solution is sealed with the film and placed in an oven at 85 degreesC for 2 days, the solution acid amount is at most 5 x 10-3 equivs. per 1 cm2 film.    An INDEPENDENT CLAIM is also included for the production of a zeolite film containing a zeolite or zeolite analogue, comprising treating with steam a filmy material comprising a zeolite or zeolite analogue seed crystal and silica.