# US 4,400,462 A · Method for the formation of photographic images > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,400,462 A - Document ID: US4400462A - Status: Granted - Kind: A - Application number: 06/268,776 - Filed: 1981-06-01 - Granted: 1983-08-23 - Earliest claimed: 1980-06-11 - Assignees: Konishiroku Photo Industry Co., Ltd. - Inventors: Kouzi Ono; Mikio Kawasaki; Mariko Natori; Eiichi Sakamoto - Web page: https://patentgrep.com/patent/US4400462A ## CPC - G03C 1/46: having more than one photosensitive layer {(G03F7/0952 takes precedence)} - G03C 8/04: the substances transferred by diffusion consisting of inorganic or organo-metallic compounds derived from photosensitive noble metals - G03C: PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES (for photomechanical purposes G03F); PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY (photographic processes characterised by the use or manipulation of apparatus classifiable per se in subclass G03B, see G03B; photomechanical production of textured or patterned surfaces G03F; electrophotography, magnetography G03G) ## Abstract Photographic materials and photographic processes employing light sensitive silver halide particles, silver halide particles which are substantially non-light sensitive having been modified with a silver halide solubility reducing agent and internally fogged silver halide particles which are substantially non-light sensitive provide negative silver images of high contrast and high maximum density. ## Claims ### Claim 1 A method for the formation of a negative photographic image comprising (a) imagewise exposing a silver halide photographic light sensitive material and (b) developing said material with a processing solution containing at least a developing agent for silver halide and an agent for dissolving metallic salt particles in which said photographic material has a support and at least one layer coated on one side having (a) light sensitive silver halide particles, (b) metallic salt particles which are substantially non-light sensitive and which are soluble in said processing solution, said metallic salt particles having been modified on the surface thereof with metallic salt solubility reducing agent, such that in its presence the solubility of the metallic salt at its surface is reduced below the metallic salt solubility in the absence of said solubility reducing agent and (c) internally fogged silver halide particles which are substantially non-light sensitive, and wherein said metallic salt particles are silver halide. ### Claim 2 (depends on 1) A method according to claim 1, wherein the light-sensitive silver halide is silver iodobromide. ### Claim 3 (depends on 2) A method according to claim 2, wherein the silver iodobromide contain 50 mole % or less silver iodide. ### Claim 4 (depends on 1) A method according to claim 1, wherein the amount of the substantially non-light-sensitive metallic salt used is in the range of 0.2 to 10 moles per 1 mole of the light-sensitive silver halide. ### Claim 5 (depends on 1) A method according to claim 1, wherein the internally fogged and substantially non-light-sensitive silver halide is silver chloride, silver chlorobromide or silver bromide. ### Claim 6 (depends on 1) A method according to claim 1, wherein the amount of the internally fogged and substantially non-light-sensitive silver halide is in the range of 0.01 to 100 moles per 1 mole of the metallic salt particles. ### Claim 7 A silver halide photographic material comprising a support and at least one layer coated thereon having (a) light-sensitive silver halide particles, (b) silver halide particles which are substantially non-light sensitive and which are soluble in a processing solution, said silver halide particles having been modified on the surface thereof with a silver halide solubility reducing agent, such that, in the presence of said agent, the solubility of the silver haldide at its surface is reduced below the silver halide solubility in the absence of said solubility reducing agent, and (c) internally fogged silver halide particles which are substantially non-light sensitive. ### Claim 8 (depends on 7) A silver halide photographic material according to claim 7, wherein said material comprises a support, a first layer which contains a mixture of said metallic salt particles and said internally fogged silver halide particles which are substantially non-light-sensitive and a second layer which contains said light-sensitive silver halide particle in this order from the support. ### Claim 9 (depends on 7) A silver halide photographic material according to claim 7, wherein said photographic material comprises a layer having said light-sensitive silver halide particles, said non-light-sensitive metallic salt particles and said internally fogged and substantially non-light-sensitive silver halide particles. ### Claim 10 A method for the formation of a negative photographic image comprising (a) imagewise exposing a silver halide photographic light sensitive material and (b) developing said material with a processing solution containing at least a developing agent for silver halide and an agent for dissolving metallic salt particles in which said photographic material has a support and at least one layer coated on one side having (a) light sensitive silver halide particles, (b) metallic salt particles which are substantially non-light sensitive and which are soluble in said processing solution, said metallic salt particles having been modified on the surface thereof with metallic salt solubility reducing agent, such that in its presence the solubility of the metallic salt at its surface is reduced below the metallic salt solubility in the absence of said solubility reducing agent and (c) internally fogged silver halide particles which are substantially non-light sensitive, and wherein said metallic salt particles are silver bromide or silver chloride particles which are not chemically sensitized.