Patent GB-964514-A (GB)
Title: Improvements in the processing of exposed photographic materials
IPC: G03C5/26
Filed: 1960-08-23
Abstract: 964,514. Photographic processes and apparatus. KODAK Ltd. Aug. 23, 1960 [Aug. 24, 1959], No. 29154/60. Headings G2A and G2C. An exposed silver halide emulsion layer is developed and fixed by contacting it with a processing web of hydrophilic organic material containing a silver precipitating agent or silver development nuclei, a silver halide solvent and an organic amino- SO 2  addition product as preservative, there being sufficient chemicals in the processing solution to develop the exposed silver halide and dissolve substantially all the unexposed silver halide and precipitate it in the processing web, and either the exposed layer or the processing web being imbibed with aqueous liquid and one of them containing a developing agent before contact. The hydrophilic web may comprise a layer of gelatin, polyvinyl alcohol, porous polyvinyl chloride, carboxylated rubber, hydrolysed cellulose acetate, cellulose ether phthalate or a copolymer of acrylic acid and ethyl acrylate,which layer may be unsupported or coated on glass metal, paper, polyethylene, polypropylene, polystyrene, polyethylene terephthalate or a cellulose ester. The web may be soaked in an aqueous solution containing the necessary chemicals and stored wet, or it may be dried and treated with aqueous liquid before use. The dried web may contain all the necessary ingredients for processing, in which case it is merely wetted with water before use, or it may contain only the precipitating agent or development nuclei, in which case it is wetted with an aqueous solution containing the processing chemicals. Alternatively, a separate dry web containing only the amine-SO 2  addition product may be used, the web being contacted before use with a processing web wet with processing solution containing the remaining ingredients. The combined webs are then brought into contact with the silver halide emulsion layer. The preferred amine for the addition product is 2, 2<SP>1</SP> -iminodiethanol, but other amines such as 2-amino-ethanol, 2-methyl (or ethyl) amino-ethanol, 2-dimethyl (or diethyl) aminoethanol, 2-aminoethylamino-ethanol, triethanolamine, 5-diethylamino-2-pentanol, 2-amino-2-methyl- 1-propanol, morpholine or piperidine may be used. The developing agent may be metol, hydroquinone, chlorohydroquinone, diaminophenols, triaminophenols, glycine, 1-phenyl-3-pyrazolidone and its derivatives catechol, pyrogallol, gallic acid, pphenylene-diamines or ascorbic acid. The silver halide solvent may be an alkali metal thiocyanate or selenocyanate, thioglycerol, an aminoethanethiol or #, #<SP>1</SP>-dithiasuberic acid, but the preferred solvent is hypo. The silver precipitant or development nuclei may be one of those commonly employed in the migratory transfer process. Fig. 2 shows a processing apparatus comprising a spool 10 for the exposed film, a spool 12 for the processing web enclosed in a tank 13 containing water or processing solution, and a processing spool 11 on which the film and wet processing web are wound together in alternate convolutions. Specifications 745,445 and 868,241 are referred to.