a) a film-forming mixture containing at least one film-forming agent is prepared b) a dose of said mixture is deposited in a cell (4) of a cellular substrate (2), the mixture having a viscosity ranging from 1 to 8000 mPa.s at the temperature of said film-forming mixture during the deposition c) said mixture is cured so as to obtain a film (6) and d) said cell (4) is closed off by a hermetic sealing means (3). The invention also relates to a device (1) especially suitable for the method and to the device intended to implement the method.
