Method for photographic replication of information on an optical data storage medium

A negative photographic process for replicating data from a master optical data storage medium, comprising,

• orienting a major surface of a fine-grained silver-halide emulsion photosensitive medium in a reference plane,
• aligning an opaque master optical data storage medium having light-transmissive areas in a plane parallel to the major surface of the photosensitive medium, in a non-contacting projection relationship therewith,
• projecting actinic radiation through said light-transmissive areas of the master, thereby forming silver latent areas in the photosensitive medium corresponding to said light-transmissive areas,
• chemically developing said silver latent image areas of the photosensitive medium, thereby forming dark filamentary, low reflective silver areas corresponding to said light-transmissive areas of the master,
• forming an areawise layer of silver precipitating nuclei at the major surface of the silver-halide emulsion in the unexposed and undeveloped region of the photosensitive emulsion,
• contacting said nuclei layer in the photosensitive medium with a reagent comprising a weak silver-halide developing agent for partial chemical development of said layer of silver precipitating nuclei and a rapid-acting silver-halide complexing solvent for reacting with unexposed and undeveloped silver-halide to form soluble silver ion complexes which are transported by diffusion transfer to said chemically developed nuclei where silver of said silver ion complexes is precipitated and adsorbed on said chemically developed nuclei in the presence of said developing agent acting as a reducing agent, thereby forming a high reflective, electrically nonconducting layer of aggregated and individual silver particles, the activity of solvent being sufficiently low to permit partial chemical development of said surface latent image by the weak developing agent before all of the undeveloped and unexposed silver-halide is dissolved where high reflective area is located in areas corresponding to opaque areas of said master.