PROCESS OF WASHING AND PROTECTING A DIFFUSION TRANSFER PHOTOGRAPHIC SILVER PRINT

• Main Authors: EDWIN H. LAND, MEROE M. MORSE
• Format: Patent
• Language: English
• Published: 13.10.1970
• Subjects: AUXILIARY PROCESSES IN PHOTOGRAPHY; CINEMATOGRAPHY; ELECTROGRAPHY; HOLOGRAPHY; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR,STEREO-PHOTOGRAPHIC PROCESSES; PHOTOGRAPHY; PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHYSICS

1,164,642. Aqueous/organic liquid polymer compositions. INTERNATIONAL POLAROID CORP. 13 Sept., 1966 [15 Sept., 1965], No. 15582/69. Divided out of 1,164,641. Headings C3F and C3P. A composition comprises a film forming polymer having acid-function groups, water, a water miscible organic liquid that is a solvent for the polymer, zinc oxide or a heavy metal salt which forms a sulphide which is insoluble in water and a volatile base in sufficient quantity to establish a pH of at least 8. The compositions exemplified are (1) a copolymer of ethylene and maleic anhydride, water, ammonium hydroxide, hydrolyzed gelatine, 2-propanol, zinc acetate and modified ammonium caseinate; (3) the butyl half ester of a copolymer of methyl vinyl ether and maleic anhydride; (4) cellulose acetate hydrogen phthalate, isopropyl alcohol, ammonium hydroxide, water and zinc acetate; (5) as (4) together with hydrolysed gelatine; (6) as (1) with the caseinate replaced by a dimethyl hydantoin formaldehyde condensation polymer; (7) as (6) with the copolymer being replaced by a phthalaldehydic acid partial acetal of polyvinyl alcohol which has been prepared by treating polyvinyl alcohol with the acid in the presence of conc. sulphuric acid; (8) as (7) with zinc oxide in place of zinc acetate.