Abstract: Film base material is provided which comprises a film of biaxially oriented synthetic linear polyester of highly hydrophobic character having superimposed thereon adherent to said film a subbing layer which contains a copolymer of vinylidene chloride, an alkyl acrylate or methacrylate, an allyl or methallyl component containing an active methylene group the monomer of which has the general formula ##STR1## wherein T is --CN or --COCH.sub.3, X is O, NH or S, and R is a hydrogen atom or methyl group and optionally at least one copolymerizable acid.The subbing layer improves the adhesion between the film support and the photographic emulsion layers and prevents the separation of the layers or frilling when the final photographic film is processed.