atives; and various kinds of synthetic hydrophilic macromolecular substances such as homopolymers or copolymers including polyvinyl alcohol, polyvinylalcohol partial acetal, poly-N-vinylpyrrolidone, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyvinylimidazole and polyvinylpyrazole.Gelatins which can be used include not only lime-processed gelatin, but also acid-processed gelatin, hyd