PURPOSE: To form a metal backing film with a good luminous reflection rate by a method wherein a dislocation is formed in an organic film and a gap, which produces when forming a metal evaporation film, is made to be the retreat of organic film cracked gas.

CONSTITUTION: A composite, wherein an acrylate emulsion as a main constituent is added by 0.01W0.5wt.% of watersoluble polysaccharide having a six member ring or of a compound thereof, is used as a filming liquid for forming an organic film and a small quantity of polysaccharide having poor compatibility with acrylresin is added to form hollows in the acrylresin being insel-like separated. In said hollows a metal evaporation film produces gaps, wherefrom cracked gas is made to escape in baking. Water emulsion of polymer of acrylate acid or acrylate acid esther, methacrylate acid or methacrylate acid esther, stylene, acrylonitrile, or of copolymer thereof is used as acrylate emulsion. When the organic film 4 is formed by heating drying, acrylate resin 6 and acrylate acid esther 7 are insel-like separated to produce a dislocation thus to produce gaps 5a when an alminium evaporation film 5 is formed.