Abstract: A method of subtitling motion picture films in which graphics elements, characters, or texts are added to a motion picture film by means of a laser beam travelling over the zone to be marked of the film, comprises the following two steps: a first step, in which a laser etching operation is performed by applying a laser beam whose speed of displacement over the film lies in the range about 1 cm/s to about 200 cm/s, with its power on the film lying in the range about 100 milliwatts to about 20 watts, and with the ratio V/P of the displacement speed expressed in cm/s divided by the power on the film expressed in watts lying in the range 10 to 30 so as to be high enough for the laser beam to achieve complete transformation of the emulsion in the etched zones by causing the emulsion to be heated, softened, and dislocated, but without totally eliminating the transformed emulsion; and a second step, in which the etched film is subjected to cleaning treatment for cleaning the etched zones so that the particles of emu