Patent GB-556858-A (GB)
Title: Improvements in or relating to colour photography
IPC: G03C7/30
Filed: 1941-12-12
Abstract: 556,858. Colour photography. DU PONT MANUFACTURING CORPORATION. Dec. 12, 1941, No. 16088. Convention date, Dec. 14, 1940. [Class 98 (ii)] Photographic material comprises a support carrying one or more light-sensitive silver halide emulsion layers and an outer layer comprising a colour-former, the outer layer being separated from the emulsion layer or layers in such manner that the latter can be developed with a colour developer without simultaneously effecting colour development of the colour-former layer, the colour-former layer being free from any substance capable of oxidizing the colour developer. The emulsion layer may be separated from the colour-former layer by a water-permeable layer of appreciable thickness, which may be formed of cellulose derivatives e.g. lower alkyl ethers and highly esterified and partially hydrolysed esters, or of gelatin, agar-agar, polyglucuronic acid, deacetylated chitin, aminocelluloses, zein derivatives, or polyvinyl alcohol hardened to be cold water insoluble. Alternatively the emulsion (which may itself contain a colour-former) and the colour-former layer are on opposite sides of a transparent water-impermeable support. In another modification, the developer oxidation products couple with dye intermediates (e.g. 1- phenyl-4:6-diketotetrahydropyridazine or perinaphthindone) in a separation layer to produce colourless compounds or extremely weakly coloured dyes. In a further modification, an unstable colour-former destroyed after processing by weak acids (e.g. phenol) may be used in a separation layer. The support may be of cellulose derivatives, or synthetic resins, e.g. polyvinyl chloride, polyvinyl alcohol, polyvinyl acetal, ethylene and isobutylene polymers, and super polyamides, e.g. nylon. Non-migratory colourformers dispersed in a water-permeable binder or film-forming colour-formers may be used. Coloured images may be formed in the emulsion layer by (1) having the colour-former and the colour-developing agent in the developer solution ; (2) having a non-migratory colour-former dispersed in the emulsion and using a developer solution containing a colour-developing agent; (3) having a non-migratory colour-developing agent dispersed in the emulsion and using a solution containing a colour-former and developer components ; or (4) having both colour-former and colour developing agent in the emulsion and using a solution containing the developer components. Alternatively, toned images may be produced in the emulsion layer. A coloured image may be formed in the colour-former layer by pressure contact with a separate layer containing an image in reducible silver salt (preferably a bleached silver image) in the presence of a colour-developing solution. The two layers may be impregnated with aqueous solutions of one or more developer components prior to contact. The colour-former layer may be impregnated with an alkaline solution and the image layer with an aqueous solution of an aromatic amino colour-developing agent. In material A, a subbed support 1 of paper or of cellulosic or resinous material containing a white pigment is coated with an emulsion layer 2, a clear gelatin layer 3, and a layer 4 comprising a gelatin dispersion of a non-migratory colour-former. In material B, a subbed cellulose acetate support 1 is coated on one side with an emulsion layer 2<SP>1</SP> and on the other with a layer 3<SP>1</SP> comprising a gelatin dispersion of a non-migratory colour-former. In material C, a fusible super polymer support 1 is coated on one side with an aqueous alkaline gelatin dispersion 3<SP>11</SP> of a non-migratory bluegreen colour-former, and on the other with a thin layer 211 comprising an aqueous alkaline dispersion of gelatin containing a mixture of non- migratory colour-formers yielding an orange-red dye, and a variable-gamma mixed emulsion layer. In material D, a transparent support 1 is coated on one side with an emulsion 5 and on the other a light-barrier layer 6 of silver dispersed in gelatin, an emulsion layer 7 containing a magenta colour-former, a clear gelatin layer 8, and a gelatin layer 9 containing a yellow colour-former. In material E a support 1 is coated on one side with a gelatin layer 10 containing a blue-green colour-former, and on the other with an emulsion layer 11 containing a magenta colourformer, and a plain gelatin layer 12. In example 1, the colour-former of layer 4 in material of Type A is the o-sulphobenzaldehyde dimer of 1- (m-octadecoylaminophenyl) - methyl - 5 - pyrazolone, and the material is printed from the red component of a tri-pack, developed in a developer containing 4-chloro-o-phenylphenol and N- diethyl-p-phenylenediamine, treated with Farmer's Reducer and washed. A positive film printed from the green component is developed, fixed, washed, bleached, and soaked in sodium carbonate solution. The colour unit is soaked in a solution containing N-diethyl-p-phenylenediamine, sodium sulphite, and metol, and the bleached position is squeegeed in register with the colour unit, the emulsion surface being in contact with layer 4 until a dye image is formed in the latter. A yellow dye image is then transferred to the colour unit by imbibition. In example 2, the blue-green component of a bipack is printed on to material of type A having as blue-green colour-former in layer 4 salicylaldehyde-osulphobenzaldehyde polyvinyl acetal, and the material is developed, fixed, and toned in a bath containing uranium nitrate, potassium oxalate, potassium ferricyanide, ammonium alum, and hydrochloric acid to give an orange-red record in layer 2. The orange-red component of the bipack is printed on to positive film, and a bluegreen image produced in layer 4 by contact as in example 1. In example 3, material of type C has as colour-formers in layer 3<SP>11</SP> a mixture of the reaction product of diacetoacettolidinesulphone with o-sulphobenzaldehyde and an osulphobenzaldehyde dimer of 1-(m-stearoylaminophenyl)-3-methyl-5-pyrazolone and in layer 2<SP>11</SP> 2-dodecoylamino-5-naphthol. The orange-red component of a bipack is printed on to layer 2<SP>11</SP> and colour developed, and an image is produced in layer 311 from a positive from the blue-green component by contact colour development. In example 4, material of type B containing in layer 31 the arylide of 1-hydroxy-2-naphthoic acid with p-dodecylanilide is printed from an orange-red component of a bipack and developed and fixed, the silver image is bleached in a bath containing potassium dichromate, potassium bromide, copper sulphate, chrome alum, and acetic acid, and the material is fixed and treated in a bath containing Wool Orange A and Serichrome Blue to give an orange-red dye-toned image, after which a bluegreen image is produced in layer 31 by contact colour development. In example 5, material of type C contains in layer 2" resorcinol-monooctadecyl-ether and in layer 3<SP>11</SP> the same colourformers as in layer 311 of example 3. An orangered component negative is printed on to layer 211, which is developed, fixed, bleached, treated in a dye-forming bath containing p-aminodiethylaniline, ammonium hydroxide, and sodium carbonate, bleached and fixed. A positive from the blue-green component is used to produce a dye image in layer 311 by contact colour development, the developer being monophenylhydrazine, aqueous sodium oleate, and sodium carbonate. In example 6, material as in example 4 contains in addition in layer 3<SP>1</SP> p-amino-N-diethylaniline. Layer 21 is processed as before, and a dye image is produced in layer 3<SP>1</SP> by contact, layer 31 having been previously soaked in hexamethylene- 1 :6 diamine solution. In example 7, material of type D has in layer 7 4: 4<SP>1</SP>-bis-(3<SP>11</SP>-methylpyrazolonyl-"')-diphenyloxide and in layer 9 diacetoacettolidinesulphone. A print is made from a blue component negative on to a positive type silver bromide emulsion on an aluminium support, and the image developed, fixed, and bleached. The green component negative is printed on to the inner emulsion layer and simultaneously in register the red component negative on to the rear emulsion layer. The material is developed to silver, and the inner silver image bleached in a solution containing nickel nitrate, potassium citrate, potassium ferricyanide, and nitric acid, and then toned magenta with alkaline dimethylglyoxime solution, and the rear image is bleached and colour developed blue-green. The silver image in this layer is bleached and the film fixed. The material is immersed in a colour developer and the layer 9 squeegeed into contact with the bleached image (previously saturated with sodium carbonate solution) on the aluminium support. In example 8, the layer 10 of material of type E contains 2 - hydroxy - 3 - methylbenzaldehydephthalaloehydic acetal of polyvinyl alcohol, and layer 11 1- (m - octadecoyiaminophenyl) - 3 - methyl - 5- pyrazolone. A green component negative is printed on to layer 11 and the material developed in a p-amino-N-diethylaniline and metoi developer. Silver and undeveloped silver salt are removed with Farmer's Reducer. The red component negative is printed on to emulsion on an aluminium support, and the latter material developed, fixed and bleached. A positive matrix is prepared from the blue-component negative by printing through the support of a film, developing in a pyro developer containing little sulphite, fixing, washing in warm water to remove unhardened gelatine, and removing the silver image. Layer 10 is floated on a colour developer and the bleached image (previously soaked in sodium carbonate solution) on the aluminium support squeegeed into contact therewith. Layer 12 is saturated with silver nitrate solution and the matrix with potassium iodide solution and squeegeed into contact. The mordanted image is dye-toned yellow with Auramine or Chrysoidine, and the film fixed. The emul-