A shrinkable iridescent film constitutes an oriented multilayer coextruded
iridescent film having at least 10 generally parallel, very thin layers of
substantially uniform thickness in which the contiguous adjacent layers
are of heat shrinkable thermoplastic resinous material, each of which is
heat shrinkable in at least one dimension in the plane of the film, the
continuous adjacent layers being substantially uniformly shrinkable so as
to have refractive indexes which differ by at least 0.03. The shrinkable
film is made by selecting appropriate thermoplastic resinous materials,
coextruding them into a thick film and then subjecting the film to
orientation below the heat set temperature of the resinous materials.