A process of producing an optical diffusion film which comprises at least a transparent
base layer on a transparent substrate, a layer of transparent microspheres over
the transparent base layer and a light absorbing layer over said transparent base
layer comprises the steps of: distributing transparent microspheres in a layer
over the transparent base layer so that each the transparent microsphere is partly
embedded in the transparent base layer; and by coating a solution layer of coloring
material that is convertible into fine metal particles and treating the solution
layer of coloring material under specified conditions so as thereby to convert
the solution layer of coloring material into a layer of fine metal particles that
are light absorbable.
