Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C8/00—Diffusion transfer processes or agents therefor; Photosensitive materials for such processes
  • G03C8/24—Photosensitive materials characterised by the image-receiving section
  • G03C8/26—Image-receiving layers
  • G03C8/28—Image-receiving layers containing development nuclei or compounds forming such nuclei

Definitions

• a receiving layer for use in the photographic diffusion transfer process comprises finely divided nonsilver noble metal nuclei obtained by reducing a metal salt in the presence of a colloid with a reducing agent having a standard potential more negative than 0.30.
• the nuclei typically have an average particle size in the range of about 15 A. to about 65 A., at least 80 percent, by number, of the' nuclei having a particle size in the range of about 20 A. to about 50 A.
• the receiving layers can be on a support such as paper or film base.
• Diffusion transfer processes are well known.
• Rott US. Pat. No. 2,352,014 describes such a process wherein undeveloped silver halide of an exposed photographic emulsion layer is transferred as a silver complex imagewise by imbibition to a silver precipitating or nucleating layer, generally to form a positive image therein.
• the silver precipitating or nucleating layer generally comprises a binder containing nuclei such as nickel sulfide, colloidal metal or the like. It is known that the particular nuclei play an extremely important role in determining the nature of the silver image which is formed in the receiving layer. For instance, depending upon the particular nuclei employed, the image formed may have inadequate density, may not have a neutral tone, i.e., may have a brownish or yellow color, may lack stability, etc.
• nuclei which have been found suitable from the standpoint of tone and/or density have had to be prepared fresh prior to coating, since they have often had poor stability on standing. For instance, when a dispersion of the nuclei is permitted to stand, the dispersion appears to lose density, probably due to a bleaching effect so that the nuclei are no longer of practical use. In addition, with many nuclei it is difficult to obtain a satisfactory tone even with a conventional toning agent, particularly when gelatin is used in the binder. Moreover, many nuclei do not provide a desirable density in the positive image.
• Silver nuclei have long been considered particularly suitable for use in diffusion transfer processes, except for the detrimental yellow color generally associated with their use. Since the image obtained in the receiving sheet is usually composed of silver deposited on a suitable site, it appeared that use of silver nuclei would facilitate the deposition of the silver on these nuclei and result in a particularly good dense image. In addition, evidence points to the importance of the shape and size of the grains which are formed by depositing the silver on the nucleating sites, and it appeared likely that silver nuclei would encourage the formation of desirable grain sizes and grain shapes.
• Carey Lea silver a colloidal silver
• the Carey Lea method of preparing colloidal silver silver nitrate is reduced in a solution of dextrin and sodium hydroxide at a pH of about 13.3.
• the average particle size is about 150 A.
• the average particle size can be reduced to about 50-70 A.
• Noble metal nuclei of metals such as palladium, platinum, gold, etc. are also known in the prior art. Particle sizes of the nuclei often range from at least 300 A. up to 2,500 A., the larger particle sizes requiring a greater concentration per square foot when coated on a receiving support. In many instances, there is a definite lack of uniformity among the particle sizes. Although the average particle size might be 500 A. for instance, there might be many of the very large sizes as well as some very small to result in a particular average size. However, nonsilver noble metal nuclei known in the art generally have not provided the desired improved properties over silver nuclei.
• nuclei which would provide improved density of a positive image which would be easy to tone and which would also behave satisfactorily when used either in a binder containing gelatin or in a polymeric binder would be very useful in diffusion transfer processes. It is also recognized that it would be desirable to obtain nuclei which can be coated at a relatively low concentration on a support and which would provide a surface which is relatively colorless or water white in nonimage areas of a positive. Such desirable results can be achieved by the practice of this invention.
• nonsilver noble metal nuclei as described herein, can be used in diffusion transfer processes to overcome several of the disadvantages described hereinbefore.
• the nonsilver noble metal nuclei of this invention are characterized by a small and uniform particle size. Their use in diffusion transfer materials and processes gives several advantages, including a significant increase in density and tone of a positive image, in comparison to the use of prior art nuclei which do not exhibit such particle size characteristics.
• Non-silver noble metal nuclei having the desired size and distribution can be prepared by reducing a nonsilver noble metal salt, in the presence of a colloid, with a reducing agent having a standard potential more negative than 0.30, e.g., a borohydride or hypophosphite, as described herein. Due to the small size of the nuclei, their particle size and distribution are difficult to measure. However, careful analysis indicates that the nuclei employed in the practice of this invention have an average particle size in the range of about IS A. to about 65 A., preferably ⁇ about 30 A. to about 60 A., at least percent, by number, of said particles having an average particle size in the range of about 20 A., to about 50 A., preferably about 25 A. to about 40 A.
• nuclei are those of the noble metals, platinum, palladium, gold, mercury, rhodium, ruthenium and osmium.
• Preferred nuclei are those of palladium and platinum, in that order. These two metals provide the greatest density in the positive image and also have a low background density or minimum density (Dmin). Palladium, in particular, provides a very low minimum density. Gold, on the other hand, does not provide as high a maximum density (Dmax) and provides a relatively high minimum density. Mixtures can be used.
• Particularly useful reducing agents which can be used in preparing nuclei according to this invention include borohydrides, such as alkali (e.g., sodium, potassium, ammonium, etc.) borohydrides which have a standard potential of l.24 measured at 25 C., and hypophosphites (H PO such as hypophosphorous acid (H PO which has a standard potential (E) of 0.50 measured at 25 C.
• H PO hypophosphites
• E hypophosphorous acid
• Preferred borohydrides for use in the invention are the alkali metal borohydrides and more particularly sodium or potassium borohydride.
• Water-soluble amine-boranes having the following structure are also useful reducing agents:
• the groups R, and R separately represent hydrogen atoms or alkyl, aryl or aralkyl groups and R represents an alkyl, cycloalkyl, aryl or aralkyl group or R and R constitute with the nitrogen atom a heterocycle and R is then a hydrogen atom.
• examples of alkyl groups are methyl, ethyl, propyl and isopropyl
• an example of cycloalkyl is cyclohexyl
• examples of aryl are phenyl and naphthyl which can be optionally substituted
• an example of an aralkyl group is benzyl and examples of nitrogen heterocyclic groups are pyridyl, morpholino and piperazyl.
• Specific compounds of the class are trimethylamine borane
• dimethylamine borane dimethylamine borane, pyridine borane, cyclohexylamine.
• the compounds may be prepared by reacting sodium borohydride, NaBI-I with a hydrochloride salt of an amine of the formula R R R N.
• amine-borane a precursor for an amine-borane as referred to above.
• gelatin e.g., gelatin
• other protective colloids e.g., polyvinyl pyrrolidone, may also be employed.
• a receiving layer for use in the diffusion transfer process can comprise the entire reaction product obtained by precipitating finely divided nonsilver noble metal nuclei from a salt of the metal by reducing the metal salt, in the presence of a colloid, to metal nuclei using a reducing agent having a standard potential more negative than -0.30.
• Particularly useful nuclei are those prepared from noble metal salts such as palladium, platinum, and gold salts, and especially preferred nuclei are those of palladium and platinum.
• the receiving element is prepared by reducing the metal salt as described above and coating the reaction product on a suitable support. In a particularly advantageous embodiment, the nuclei are coated at about 1 to about 200 zg./ft.
• the receiving element as described above is used advantageously to provide a photographic print having an image in the receiving layer on a support.
• the image is obtained by the diffusion transfer process and is formed in the receiving layer which comprises a colloid binder and the nonsilver noble metal nuclei of our invention. Particularly good results are obtained using palladium and platinum nuclei.
• palladium nuclei are prepared by reducing a palladium salt such as ammonium chloropallidate in an aqueous solution containing a colloid, such as gelatin, preferably using a borohydride reducing agent such as potassium borohydride.
• a palladium salt such as ammonium chloropallidate
• a colloid such as gelatin
• the reducing agent is used slightly in excess and the reaction mixture heated to about 70 C for about 5 minutes. Additional colloid and other addenda can then be added and the mixture coated on a suitable support such as baryta coated paper.
• 14 micrograms of palladium nuclei in 80 milligrams of gelatin is coated per square foot of support.
• the nucleated layer having the nonsilver noble metal nuclei thereon is overcoated with a substantially unhardened silver halide emulsion.
• a substantially unhardened silver halide emulsion Particularly useful emulsions are described in Yackel et al., US. Pat. No. 3,020,155.
• the emulsion is developed with a silver halide diffusion transfer type developing solution containing a silver halide developer such as hydroquinone and also containing a silver halide complexing agent such as sodium thiosulfate.
• the unhardened silver halide emulsion is then removed by washing with warm water.
• the nuclei of this invention are prepared in a suitable colloid suspension.
• a hydrophilic colloid such as gelatin.
• any suitable colloid or colloids may be used, including both water-soluble polymers and water-insoluble polymers.
• a latex or hydrosol may advantageously be employed if the polymer is insoluble in the liquid used to carry out the reduction.
• the amount of colloid can be varied depending upon the particular colloid, reducing agent, ratio of proportions, etc. Typically about 0.5 percent to about 20 percent, by weight, based on the total reaction mixture of colloid is used, preferably from about 1 percent to about 10 percent.
• a water-soluble metal salt is used which is dissolved in water which either contains a colloid or to which the colloid is added.
• the borohydride reducing agent is then added to the solution, usually at a pH of about 6 until the pH reaches about 8.5, typically at temperatures of 0-95 C., preferably 20-70 C.
• the time allowed for the reaction to be completed depends upon the reducing agent, colloid, metal salt used, temperature, etc. Usually from 3 minutes to about 2 hours are sufficient, but greater or less time may be adequate.
• the reaction mixture can then be coated directly on an appropriate support for use as a receiving sheet in the diffusion transfer process or additional colloid can be added to the reaction mixture before coating.
• colloid can be incorporated in the coating composition.
• Any suitable colloid may be used.
• Particularly useful colloids are those which are used for binders in silver halide emulsions.
• they are coated in a range of about 5-500 mg./ft.
• Included among the suitable colloids are gelatin, preferably coated at a level in the range of about 7-lOO mg./ft.
• polymeric latices such as copoly(2-chloroethyl methacrylate-acrylic acid) preferably coated in the range of 15-350 mg./ft.
• colloids may be used as dispersing agents or as binders for the nuclei of our invention.
• the use of these various colloid materials results in varying the aspects of the process such as the time of contact between the negative and the receiver sheet, the speed of transfer, the tone and the like.
• latex materials are suitable for use as vehicles for nuclei, it will be appreciated that some latex formulations are also difficult to successfully coat with consistently good results, especially without mottle.
• Coating solutions containing polymers are also useful.
• a particularly useful polymer coating solution which has a viscosity resembling gelatin solutions and can be hardened with an aldehyde comprises polyvinyl quaternary salts containing aldehyde hardenable groups.
• toners, surfactants, coating aids, developing agents, stripping agents, silver halide solvents etc. may be added to improve the image quality in the receivingsheet.
• the concentration on the receiving sheet can be very low, suitable concentrations being about 1 to about 200 zg./ft. 6 to 100 zg./ft.
• the size of the particles of the nuclei can be determined using an electron microscope. In a convenient method of preparing the nuclei for examination,
• discrete nuclei are prepared in a suitable colloid, such as a salt. Accordingly, it is within the scope of the invention to include in the receiving layer, nuclei having the specified size and specified size distribution, plus the reaction byproducts which are obtained during the reducing operation.
• the supports which can be used for coating with the receiving layer are any of those which are suitable and include paper, wood, glass, plastics, etc.
• a particularly useful support is baryta coated paper.
• a polymeric material which acts as a moisture barrier such as polyethylene or the like, which is pigmented to provide a white surface is used.
• Other polymeric materials which may be used as coatings on paper or as self-supported webs include polyesters, polyamides, polycarbonates, polyolefins, cellulose esters, polyacetals and the like.
• treatments of the support e.g., photographic film base, may be carried out including subbing the support, electron bombardment, treating with peroxide and the like.
• the nuclei can be coated in a polyethylene latex.
• polyethylene latex may be used as a dispersing medium when the nuclei are formed or the polyethylene latex may be added to the reaction mixture after the nuclei have been formed in the presence of some other colloid.
• a polyethylene latex may also be used with other nucleating or silver precipitating materials, including metal sulfides and the like.
• the nuclei may be formed in situ by coating a layer of nonsilver noble metal salt in a colloid on a support and overcoating with a layer of reducing agent.
• a coating containing gelatin and gold chloride may be coated on a suitable support over which is then coated a layer containing sodium borohydride.
• improved results are obtained by carrying out the reduction in a reaction vessel and then coating on a suitable support.
• the receiving sheet may also contain various toning agents or these toning agents may be in the processing solution or even, in some instances, contained in the silver halide emulsion.
• Toning agents which may be included for improving the image include sulfur compounds such as Z-mercaptothiazoline, 2-amino-5-mercapto-1,3,4- thiadiazole, 2-thionoimidazolidene, Z-mercapto-S-methyloxazoline and 2-thionoimidazolyne.
• These toners are particularly useful in a range of 0.01 to 3.0 mg./ft. either in the receiving layer or coated in a layer on top of the nucleated layer.
• toners can be used either alone or in conjunction with other toning agents.
• Other toning agents which may be used include the S-mercaptotetrazoles of Abbott et al., U.S. Pat. No. 3,295,971 and Weyde, U.S. Pat. No. 2,699,393. Still other toning agents are disclosed in Tregillus et al., U.S. Pat. No. 3,0l 7,270.
• the nuclei of the invention may also be precipitated in colloidal dispersions which also have therein particles such as silica, bentonite, diatomaceous earth such as Kieselguhr, powdered glass and fullers earth.
• colloids and colloidal particles of metal oxides such as titanium dioxide, colloidal alumina, coarse aluminum oxide, zirconium oxide and the like may be used with the nuclei.
• the exposed silver halide emulsion is contacted against a web in which has been imbibed some or all of the processing solutions.
• the processing solutions and other components of the web and/or the emulsion can be adjusted so that either a useable negative is obtained in the emulsion layer or a useable positive in the web, or both a useable negative and a useable positive.
• the web is nucleated with silver precipitating nuclei. 1
• the nuclei of the invention are especially suitable for use in the web processing system.
• the web comprises a support carrying a layer of gelatin which contains nuclei such as those described in this application.
• the web is soaked with a desired processing solution prior to use and then placed in close contact with an exposed negative for a time which depends upon the particular components used.
• the two films are then separated, revealing a positive image in the web material.
• a cover sheet may be applied over the negative or processing web after they have been separated for ease of handling or to improve stability of the images therein.
• Typical processing webs and processes of using processing webs are disclosed in U.S. Pat. No. 3,l79,5l7 issued Apr. 20, 1965 to Tregillus et a].
• the silver halide emulsion is exposed to a light image after which it is contacted with a silver halide developing agent containing a silver halide complexing agent.
• the exposed emulsion is developed in the light areas and the unexposed silver halide is complexed with the silver halide complexing agent after which the emulsion is contacted against the receiving sheet and the complex silver halide diffuses imagewise to the receiving sheet containing nuclei.
• a simple stabilizing method merely involves washing the print in order to remove any processing chemicals which may remain thereon. However, the washing step does not protect the print from subsequent chemical reactions with oxygen, hydrogen sulfide, etc., in the atmosphere, which have an adverse effect on the stability of the silver image.
• Suitable print coating compositions may also employ a polymeric material such as methylmethacrylate-methacrylic acid copolymer or the combination of an acid group or sulfate group containing polymer such as copoly(methylmethacrylate-methacrylic acid) and a hydantoin-formaldehyde condensation polymer, such as that disclosed in French Pat. No. 1,493,188.
• a heavy metal salt such as zinc acetate may also advantageously be incorporated in the print coating composition. Further improvement is obtained by incorporating in the coating composition an acid such as acetic acid, propionic acid or the like.
• a solution e.g., an aqueous solution of a strong reducing agent, such as sodium borohydride
• a diffusion transfer process such as described in U.S. Pat. No. 2,698,237 of Land issued Dec. 28, 1954.
• Application of this solution can return the developed image to a neutral black tone should undesired loss of black tone or loss of image resulting from affects of hydrogen sulfide in the atmosphere, highly humid keeping conditions or the like have occurred.
• a l0 percent, by weight, aqueous solution of sodium borohydride is especially suitable, but other reducing agents are effective, e.g., stannous chloride, hydrazine and ascorbic acid.
• a stabilizer solution e.g., an aqueous solution containing equal parts, by weight, water and methanol
• a cationic stabilizer such as a phosphonium or quaternary ammonium stabilizer, such as poly l,2-dimethyl-S- vinyl pyridinium methyl sulfate, 2-methyl-3-ethyl benzothiazolium para toluene sulfonate, tetrabutyl phosphonium chloride, or triphenyl benzyl phosphonium chloride.
• a concentration of the described stabilizer of about 0.5 to about 3 milligram
• the silver halide emulsions employed in this invention can contain incorporated addenda, including chemical sensitizing and spectral sensitizing agents, coating agents, antifoggants and the like. They can also contain processing agents such as silver halide developing agents and/or developing agent precursors. Of course, the processing agents can be incorporated in a layer adjacent to the silver halide emulsion if desired.
• the developing agents and/or developing agent precursors can be employed in a viscous processing composition containing a thickener such as carboxymethyl cellulose or hydroxyethyl cellulose.
• a thickener such as carboxymethyl cellulose or hydroxyethyl cellulose.
• the silver halide developing agents used for. initiating development of the exposed sensitive element can be the conventional types used for developing films or papers with the exception that a silver halide solvent such as sodium thiosulfate, sodium thiocyanate, ammonia or the like, is present in the quantity required to form a soluble silver complex which diffuses imagewise to the receiving support.
• a silver halide solvent such as sodium thiosulfate, sodium thiocyanate, ammonia or the like
• concentration of developing agent and/or developing agent precursor employed is about 3 to about 320 mgJft. of support.
• the developing agents and/or developing agent precurso can be employed alone or in combination with each other, as well as with auxiliary developing agents.
• Suitable silver halide developing agents and developing agent precursors which can be employed include, for example, polyhydroxybenzenes, such as hydroquinone developing agents, e.g., hydroquinone, alkyl substituted hydroquinones, as exemplified by t-butyl hydroquinone, methyl hydroquinone and 2,5-dimethylhydroquinone, catechol and pyrogallol; chloro substituted hydroquinones such as chlorohydroquinone or dichlorohydroquinone; alkoxy substituted hydroquinones such as methoxy hydroquinone or ethoxy hydroquinone;
• Lactone derivative silver halide developing agents which have the property of forming a lactone silver halide developing agent precursor under neutral and acid conditions are particularly useful.
• Typical lactone derivatives are described in copending U.S. application Ser. No. 764,348 filed Oct. l, l968 entitled Photographic Compositions and Processes" in the name of Oftedahl.
• the particularly suitable lactone derivatives provide desired developing activity and reduction of stain without adversely affecting desired maximum density, minimum density, photographic speed and other desired sensitometric properties.
• Suitable lactone derivative developing agents include those which under neutral, slightly alkaline or acid conditions, i.e., when the pH is lowered to a level of about 9 or lower, i.e., about 2 to about 9, do not have significant developing activity, if any, due to formation of a developing agent precursor.
• hydroxy cinnamic acid and/or amino cinnamic acid developing agents can be employed.
• Suitable hydroxy cinnamic acid or amino cinnamic acid developing agents include any such compounds which cause reduction of a photographic silver salt in exposed areas of a layer containing such photographic silver salt without adversely affecting the unexposed areas of the photosensitive silver salt.
• Especially suitable developing agents are derivatives of 6-hydroxy coumarins, 6-amino coumarins, mixtures thereof and their salts, e.g., water-soluble salts.
• combinations of developing agents can be used in the diffusion transfer process.
• Particularly useful developers include combinations of the following:
• the photographic emulsions employed can be X-ray or other nonspectrally sensitized emulsions or they can contain spectral sensitizing dyes such as described in U.S. Pat. Nos. 2,526,632 of Brooker et al. issued Oct; 24, 1950 and 2,503,776 of Sprague issued Apr. 1 1, 1950.
• Spectral sensitizers which can be used include cyanines, merocyanines, styryls and hemicyanines.
• the photographic emulsions can contain various photographic addenda, particularly those known to be beneficial in photographic compositions.
• the various addenda and concentrations to be employed can be determined by those skilled in the art.
• Suitable photographic addenda include hardeners, e.g., those set forth in British Pat. No. 974,3 l7; buffers which maintain the desired developing activity and/or pH level; coating aids; plasticizers, speed increasing addenda, such as amines, quaternary ammonium salts, sulfonium salts and alkylene oxide polymers; and various stabilizing agents, such as sodium sulfite.
• the photographic silver salt emulsions of the invention can be chemically sensitized with compounds of the sulfur group such as sulfur, selenium and tellurium sensitizers, noble metal salts such as gold, or reduction sensitized with reducing agents or combinations of such materials.
• photographic silver salts can be used in the practice of the invention. These include photographic silver halides such as silver iodide, silver bromide, silver chloride, as well as mixed halides such as silver bromoiodide, silver chloroiodide, silver chlorobromide and silver bromochloroiodide. Photographic silver salts which are not silver halides can also be employed such as silver salts of certain organic acids such as silver behenate, silver-dye salts or complexes, etc.
• the photographic silver salts are typically contained in an emulsion layer comprising any of the known binding materials suitable for photographic purposes.
• binding materials suitable for photographic purposes.
• These include natural and synthetic binding materials generally employed for this purpose, for'example, gelatin, colloidal albumin, water-soluble vinyl polymers, such as mono and polysaccarides, cellulose derivatives, proteins, water-soluble polyacrylamides, polyvinyl pyrrolidone and the like, as well as mixtures of such binding agents.
• the elements can also contain stripping layers and/or antistatic layers (i.e., conducting layers).
• Stripping agents can be used either on the surface of the silver halide emulsion layer, on the receiving layer containing the nuclei, or can be contained in the developing or processing solutions. When added to the processing solution in concentrations of about 3 percent to about 10 percent, by weight, the stripping agents prevent the processing solution from sticking to the receiver. Suitable stripping agents normally are used which have a composition different from the binder used in the silver halide emulsion.
• Typical stripping agents include alkali permeable polysaccharides such as, for example, carboxymethyl cellulose or hydroxyethyl cellulose, 4,4'-dihydroxybiphenol, glucose, sucrose, sorbitol (hexahydric alcohol CGHB(OH) inositol (hexahydroxy-cyclohexane fi 6(O )6 21-1 resorcinol, phytic acid sodium salt, thixcin (a castor bean product), zinc oxide, and finely divided polyethylene. These coatings are relatively thin having a preferred coverage of about 6.0 mg./ft.. However, a useful range may be from 1.0 mg. to 1.0 g./ft. It will also be understood that a stripping agent or release agent can be incorporated in the receiving layer along with the nuclei and/or binder used as a carrier for the nuclei.
• alkali permeable polysaccharides such as, for example, carboxymethyl cellulose or hydroxyethy
• the nuclei can be carried in the developing or processing solution to form the receiving layer.
• the use of nuclei in the processing solution permits use of receiving surfaces which have not been specifically prepared as receiving layers.
• developing or processing solutions containing nuclei can be used with receiver sheets having thereon a coating containing the nuclei of this invention.
• % Saponin solution To 100 ml. portions of Solution A are added (1) 2.50 ml. of palladium chloride solution at 1.25 mg./ml. of solution; (2) 5.0 ml. of reducing agent solution and (3) distilled water to bring the total volume of each solution to 1 18 ml.
• the samples are held for 30 minutes at 70 C. All of the solutions are then coated at 0.002 inch on a polyethylene coated paper support to give a nuclei coverage of about 75 ugjft. and about 80 mg./ft. of latex (solids). All of the coatings are made at 100 F. and cured at 205 F. for 1 minute.
• the receiving sheet is used in a photographic silver salt diffusion transfer process with an exposed silver chlorobromide emulsion and a developer having the following composition:
• EXAMPLE 3 Platinum Nuclei Strong reducing agents (e.g., borohydride) produce nuclei by the method of Example 1 which result in high transfer density and line particle size.
• reducing agents e.g., borohydride
• the resulting solution is coated on a polyethylene-coated paper support.
• Reducing agents other than hypophosphorous acid can be used, such as its sodium salt or the like.
• Other watersoluble salts of palladium, such as palladium nitrate or ammonium chloropallidate can be used.
• Cadmium sulfide is-prepared in a latex having the same composition in a manner similar to the above procedure, but
• a coating solution containing colloidal CdS nuclei is prepared by adding Solution C to Solution D.
• Solution C 0.02 M Cd(C,l 1;,O,) Solution D 4 ml. Latex 60 m1. Distilled water 210 ml. lsopropanol 50 ml. Na,S-a9H,O 3 ml. Polyoxyethylene ether alcohol 0.4 ml.
• nonionic wetting agent A silver bromoiodide gelatin emulsion coated on a support is exposed and the above receiving sheets tested with it and a developer having the following composition:
• EXAMPLE 5 Cellophane, 1.6 mils in thickness, is nucleated by the following treatment to form a processing web: A sample is first bathed for 3 minutes in a 0.1 percent gold chloride solution and then bathed for 3 minutes in an alkaline 0.2 percent solution of potassium borohydride. This treatment forms metallic gold nuclei on the cellophane sheet. After washing for 3 minutes, the nucleated sheet is contacted for 30 seconds with a developer having the composition listed below, rolled in contact with a suitably exposed negative, after which the two are separated. A fully developed negative image forms on the exposed film.
• the cellophane sheet shows bronzing and a high minimum density.
• the minimum density is 0.5 compared to a maximum density of 1.3, or a density difference of 0.8. This is a poor density difference and is not an acceptable image.
• EXAMPLE 6 In situ Preparation Part A Potassium choraurate is dispersed in a physical mixture of 9 parts latex containing polymeric material prepared from a mixture consisting of 2-chloroethyl methacrylate and acrylic acid in a ratio of 98:2 and one part of a polymeric latex con sisting of N-butyl acrylate and acrylic acid in a ratio of 9:1 and coated on a polyethylene-coated paper support at 0.144 mg./ft.
• Receiver Dmax Dmin Tone A 1.33 0.14 cold B 1.53 0.11 fairly cold A and B are overcoated with solutions of hypophosphorous acid and processed as above with similar results.
• EXAMPLE 7 Palladium Nuclei vs. Cadmium Sulfide, CLS and Silver Sulfide Nuclei in Latex
• a coating solution containing colloidal palladium nuclei is prepared by adding Solution A to Solution B with vigorous stirring at 25 C. The mixture is heated to 70 C. for one hour, then cooled.
• Anionic wetting agent 1 ml.
• a yellow colloidal dispersion of CdS in latex is prepared: 5 g. of the latex used above in Solution B is dispersed in 35 ml. distilled water; to this is added 30 m1. ofa 20 percent cadmium acetate (-2 H O) solution and then 30 ml. of 1 percent sodium sulfide ('9 H O), dropwise with good stirring at 72 F.
• -2 H O 20 percent cadmium acetate
• '9 H O 1 percent sodium sulfide
• Carey Lea silver is prepared in a latex having the above composition by mixing 10 ml. of a colloidal Carey Lea silver dispersion with 40 ml. ofa 1 percent latex solution.
• Silver sulfide nuclei coated in a latex are prepared as above for the CdS using a silver sulfide dispersion.
• Palladium Metal Nuclei in a Colloidal Silica Vehicle A coating solution containing colloidal palladium nuclei is prepared by adding Solution A to Solution B with vigorous stirring at 25 C.
• Solution B Colloidal dispersion of SiO, ml.
• the above nuclei are coated on polyethylene-coated paper at 160 mg./ft. silica and 0.15 mg./ft. palladium metal and tested as in Example 1 to give a silver image of very good quality.
• EXAMPLE 9 Noble Metals in Latex To 100 ml. portions of Solution A are added: (1) metal salt solutions at 2.0 mg. metal salt/ml. solution (except PdCl solution which is at 1.25 mg./ml. solution) in the amounts listed in Table 1 below; (2) 5.0 ml. of NaBH solution except for coatings A and B in which 0.05 ml. of commercial H PO is used as the reducing agent, and (3) distilled water to bring the total volume of each solution to 1 18 ml.
• Nuclei Dispersion A 20%, by weight. gelatin in water 90 g.
• a coating composition having the following components is prepared:
• composition is coated on cellulose acetatefilm support to form a nucleated web and dried.
• the nucleated web is then immersed for 3'minutes in a processing solution having the following composition:
• EXAMPLE 1 l A processing web is prepared as in Example 10 except that the following coating composition is applied to the film support:
• Example 10 After imbibing with the processing solution of Example 10, the web is rolled in contact with an exposed silver positive and negative images.
• EXAMPLE 12 Size Frequency Study Pictures are obtained as in Example 1 using platinum nuclei formed by means of borohydride reduction. A size frequency count involving 86 nuclei particles show that about percent of the particles are less than 40 A. in diameter with the following distribution:
• nuclei having an average particle size in the range of about A. to about 65 A., at least about 80 percent, by number, of said nuclei having a particle size in the range of about A. to about 50 A.
• a receiving element comprising a support having thereon said receiving layer of claim 1.
• a receiving element according to claim 2 in which said nuclei are coated on said support in an amount of about I to about 200 ugJftF.
• a photographic element comprising a support having thereon said receiving layer of claim 1 and having over said layer an overcoat of a photographic silver halide emulsion.
• a photographic element comprising a image in a receiv' ing layer on a support, said silver image obtained by a silver ion diffusion transfer process, said receiving layer comprising a colloid binder and nonsilver noble metal nuclei, substantially all nuclei in saidlayer having a particle size in the range of about 15 A. to about 65 A. and about 80 percent of the total number of said nuclei having a particle size in the range of about 20 A. toabout 50 A.
• a receiving layer for use in the diffusion transfer process comprising a reaction product obtained by forming finely divided nonsilver noble metal nuclei from a salt of said metal by reducing said metal salt, in the presence of a colloid, with a reducing agent having a standard potential more negative than 0.30.
• a receiving layer of claim 10 which comprises polymeric latex vehicle for said nuclei.
• a receiving layer of claim 10 which comprises a gelatin vehicle for said nuclei.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Photosensitive Polymer And Photoresist Processing (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)
• Thermal Transfer Or Thermal Recording In General (AREA)
• Manufacture Of Metal Powder And Suspensions Thereof (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=25168468

Family Applications (1)

Country Status (7)

Cited By (20)

Families Citing this family (3)

Citations (5)

• 1969
  • 1969-02-04 US US796552A patent/US3647440A/en not_active Expired - Lifetime
• 1970
  • 1970-01-30 BR BR216490/70A patent/BR7016490D0/pt unknown
  • 1970-01-30 GB GB1290618D patent/GB1290618A/en not_active Expired
  • 1970-02-02 JP JP45008559A patent/JPS491571B1/ja active Pending
  • 1970-02-02 BE BE745363D patent/BE745363A/fr unknown
  • 1970-02-03 FR FR7003693A patent/FR2033885A5/fr not_active Expired
  • 1970-08-26 DE DE19702004798 patent/DE2004798B2/de active Granted

Patent Citations (5)

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