Photographic materials

Claim 1

a method as set forth in claim 1 in which said light-decomposable agent is a diazo compound.

Claim 3

A method of preparing vesicular images comprising: exposing to image forming light a photographic material capable of furnishing a record solely in the form of a distribution pattern of radiation scattering discontinuities formed within an otherwise substantially homogeneous vehicle, said material being in the form of a dry, water-resistant non-hygroscopic film, the continuous phase of said film consisting essentially of a synthetic, water-insoluble, non-water swelling highly linear thermoplastic formaldehyde polyvinyl acetal consisting essentially of vinyl formal units, vinyl alcohol units and units of vinyl ester with a fatty acid containing up to six carbon atoms, at most 25 percent of said repeating units being vinyl alcohol and at least 50 percent of said repeating units being vinyl formal, and a light decomposable solid agent substantially uniformly dispersed therein as the sole essential decomposable agent, said decomposable agent itself being non-reactive to said vehicle and, upon exposure to light, decomposing into products which are chemically non-reactive to said vehicle and which upon warming form said radiation scattering discontinuities only in the light struck areas in said polymer to thereby furnish said record, said photographic material being obtained by combining said polymer and said decomposable agent in non-aqueous organic solvent for them to form a uniform, essentially water-free mixture thereof and forming the photographic material by removal of said solvent, diffusing said volatile products from said vehicle without forming an image therein, subjecting said vehicle to substantially uniform irradiation to cause decomposition of an additional quantity of said decomposable agent, and heating said photographic material to cause development and the formation of a vesicular image.