NOVELTY - A film (F1) is made from a material having denatured clay and an additive, where the weight ratio of the denatured clay is not less than 70% relative to total solids.    USE - As a film comprising self-supporting film, multilayer film, and surface protective film (where material to be protected is metal, metal oxide, ceramics, plastics, plastic foamed material, wood, plaster or rubber); and for sealing material, packaging material, protective material, heat insulating material, electric insulating material, heat resistant material, noncombustible material or fuel cell membrane (all claimed). Also useful in manufacturing articles such as liquid crystal display (LCD) substrate film, organic electroluminescent (EL) substrate film, electronic paper substrate film, electronic device encapsulating film, substrate film for various functional films, flexible film for other kinds of electronic device, fuel cell sealing film, solar battery film, food packaging film, beverage packaging film, medicinal-product packaging film, packaging film for daily necessities, packaging film for industrial articles, as a packaging film for other various articles, and gas-barrier sealing material against gaseous species such as carbon dioxide and hydrogen, multilayer packaging film, oxidation-resistant film, corrosion-resistant film, weather-resistant film, flame-resistant film, heat-resistant film, and chemical-resistant film.    ADVANTAGE - The film has improved light transmittance, gas barrier properties, water-vapor barrier properties and mechanical strength; has a permeability coefficient to oxygen gas of less than 2x 10-9 cm2s-1cmHg-1 at room temperature; has water-vapor permeability at 40 degrees C and 90% relative humidity of less than 10 gm-2 day-1; has water absorption rate at 20 degrees C and 65% relative humidity of less than 2%; exhibits no visibly observable damage in shape, and has a permeability coefficient to oxygen gas of less than 2x 10-9 cm2s-1cmHg-1 at room temperature, after immersion for 1 hour in superheated water at 150 degrees C; and shows 5 wt.% reduction temperature of 235-760 degrees C as measured by thermogravimetry. The volume resistivity in a direction perpendicular to the film is at least 2.8x 1011 Omega cm. The ion conductivity in a direction perpendicular to the film is at least 1x 10-4 Scm-1. The film is capable of being used without cracking at a bending radius of 8 mm. The average linear thermal expansion coefficient of the film from 50-250 degrees C in a direction parallel to the film plane is 5-10 ppm. The multilayer film has a permeability coefficient to oxygen gas of less than 2x 10-9 cm2s-1cmHg-1 at room temperature; and water-vapor permeability at 40 degrees C and 90% relative humidity is less than 6 gm2day-1. The denatured clay film has excellent heat resistance, excellent pliability, excellent gas barrier properties, excellent water-vapor barrier properties, and high water resistance.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following    (1) a multilayer film (F2) comprising a film A, and a film B, where the constituents of A and B are not same;    (2) a composite multilayer film (F3) comprising the films (F1) and (F2), and at least one of metal foil, plastic film, rubber and paper; and    (3) manufacturing the film (F1) involving preparing denatured clay pre-gel by adding a pre-gel solvent of denatured clay; adding a polar solvent; and then adding an additive.