a method for producing a plastic film having improved characteristics , which consists in nebulizing on the faces , in the region downstream of the extruder , at least one “ active substance ” or a mixture of “ active substances ”, utilizing the various states of aggregation of the product generated by the temperature distribution . these substances modify the structure of the film , in particular its surface structure , by bonding and penetrating to a depth which is a function of the temperature , of the material of the film and of the type of substance used .