United States Patent (19) 11) 4,267,254 Bloom, deceased et al. (45) May 12, 1981 (54) PHOTOGRAPHIC PROCESS Louis et al., Inorganic Nuclear Chem. Letters, vol. 13, (75) Inventors: Stanley M. Bloom, deceased, late of 1977, pp. 31-35. Waban, Mass., by Arlene N. Bloom, Primary Examiner-Richard L. Schilling executrix; Krishna G. Sachdev, Attorney, Agent, or Firm-Gaetano D. Maccarone Cambridge, Mass. 57 ABSTRACT 73) Assignee: Polaroid Corporation, Cambridge, Mass. There is described a photograhic method employing a positive-negative diffusion transfer film unit wherein (21) Appl. No.: 80,349 there is formed a positive silver transfer image which (22 Filed: Oct. 1, 1979 may be viewed as a positive transparency without being separated from the developed negative silver image, (51) Int, Cl...... G03C 5/54; G03C 7/00; including an embodiment wherein additive color pro GO3C 5/38 jection positive images are formed. According to the 52 U.S. Cl...... 430/245; 430/251; method, the exposed film unit is developed by contact 430/428; 430/455 ing the silver halide emulsion layer with a photographic 58) Field of Search ...... 430/245, 246, 251, 428, processing composition which comprises an aqueous 430/455 alkaline solution containing a silver halide developing (56) References Cited agent and a silver complexing agent. The silver com U.S. PATENT DOCUMENTS plexing agent is stable in an alkaline environment, has a melting point less than about 50° C. preferably about 25 3,062,646 1 1/1962 Dann et al...... 430/600 3,930,867 1/1976 Bigelow ...... 430/600 C. or less, and the log of the stability constant (3) for a 3,975,423 8/1976 Borror et al. . ... 430/251 1:1 complex of the complexing agent with silver is at 4,017,314 4/1977 Blake ...... 430/485 least about 10.5. The film unit is not washed during the 4,168,166 9/1979 Land ...... 430/245 method. According to the method of the invention crystal formation in the transparency is substantially or OTHER PUBLICATIONS completely eliminated. Pelissard et al., Tetrahedron Letters, vol. 45, 1972, pp. 4589-4592. 15 Claims, No Drawings 4,267,254 1. 2 in the positive silver transfer image is substantially or PHOTOGRAPHIC PROCESS completely eliminated. The present application is drawn to such a method. BACKGROUND OF THE INVENTION This application relates to a photographic diffusion SUMMARY OF THE INVENTION transfer method and, more particularly, to such a It is, therefore, the object of this invention to provide method wherein there are utilized silver complexing a novel photographic diffusion transfer method. agents having advantageous properties. It is another object to provide a method which pro The use of silver complexing agents, also referred to vides positive silver transfer images which may be as "silver halide solvents', in diffusion transfer photo 10 viewed as positive transparencies without being sepa graphic methods is known in the art. In methods of this rated from the developed silver negative image. type an exposed silver halide emulsion is developed by contacting it with a photographic processing composi It is a further object to provide a method for forming tion whereby an imagewise distribution of diffusible additive color positive images which are viewed by image forming components is formed in the unexposed 5 projection upon a viewing surface without being sepa and undeveloped areas of the silver halide. This image rated from the developed negative silver image. wise distribution of image forming components is trans Still another object is to provide a photographic dif ferred to an image receiving stratum which is in super fusion transfer method wherein the film unit is not posed relationship with the silver halide emulsion layer washed during processing. to provide the desired transfer image. 20 It is yet another object of the invention to provide a In diffusion transfer methods wherein a silver transfer diffusion transfer method which utilizes silver complex image is formed, the method is carried out in the pres ing agents having physical properties such that the ence of a silver complexing agent which forms a soluble formation of crystals in the positive silver transfer and diffusible complex with undeveloped silver halide. image is substantially or completely eliminated. The soluble silver complex which is formed diffuses to 25 the superposed image receiving layer where metallic BRIEF SUMMARY OF THE INVENTION silver is deposited to provide the desired silver transfer These and other objects and advantages are accom image. plished in accordance with the invention by providing a Various materials have been taught as being useful as photographic method employing a positive-negative silver complexing agents in positive-negative diffusion 30 diffusion transfer film unit wherein there is formed, transfer photographic methods. Among these are thio without washing, a positive silver transfer image which sulfates, such as potassium and sodium thiosulfate; thio cyanates such as potassium and sodium thiocyanate; may be viewed as a positive transparency without being cyclic amides such as barbituric acid and uracil; 1,1-bis separated from the developed negative silver image. sulfonyl alkanes such as are disclosed in U.S. Pat. No. 35 According to the method, the exposed film unit is de 3,769,014; and alkylthioalkyl-substituted alkylsul veloped by contacting the silver halide emulsion layer fonylacetonitriles such as are disclosed in U.S. Pat. No. with a photographic processing composition which 3,975,423. These materials have been found to be suit comprises an aqueous alkaline solution containing a able for performing their intended functions. Neverthe silver halide developing agent and a silver complexing less, they are not completely satisfactory in every type agent. The silver complexing agent is stable in an alka of positive-negative diffusion transfer film unit wherein line environment, has a melting point of less than about a silver transfer image is formed. 50° C., preferably about 25°C. or less, and the log of the For example, there are known, in the art, diffusion stability constant (3) for a 1:1 complex of the complex transfer methods which are adapted to provide positive ing agent with silver is at least about 10.5. The preferred silver transfer images which may be viewed as positive 45 silver complexing agents are liquids at room tempera transparencies without being separated from the devel ture. oped negative silver image, including methods for form By "stable in alkaline environment' as used in the ing additive color positive images which are viewed by present application is meant that the complexing agent projecting the transparency on a viewing surface. The retains at least 75% of its silver complexing ability after film units employed in such methods are retained intact 50 during processing and are not washed. Accordingly, the being in a IN sodium hydroxide solution for twenty silver complexing agent, which typically may comprise four hours at room temperature. from about 3 to about 15 percent by weight of the pho It has been found that the use of such silver complex tographic processing composition, remains in the image ing agents, because of their physical properties, contrib receiving layer where the silver transfer positive image 55 utes to the substantial or complete elimination of crystal is formed. Because of factors such as the amount of the formation in the transparency. Consequently, such sil silver complexing agent present in the film unit and the ver complexing agents may be used in the amounts physical properties of the known silver complexing typically required to effect rapid and substantially com agents, many of which have relatively high melting plete transfer of the positive silver transfer image form points, the known complexing agents tend to form crys ing components to the image-receiving layer while at tals within a relatively short time, e.g., as brief as a day the same time substantially or completely eliminating after formation of the image. Such crystal formation is the difficulties with crystal formation which have been undesirable because it detracts from the aesthetic qual encountered heretofore. Further, it has been found that ity of the image and in the case of projection transparen silver complexing agents having the specified physical cies adversely affects the quality of the projected image 65 properties may be used in combination with other silver for viewing. complexing agents which do not possess all of the same Thus, it would be desirable to provide a diffusion properties to provide the advantageous results which transfer method of this type wherein crystal formation are obtained according to the method of the invention. 4,267,254 3 4. DESCRIPTION OF THE PREFERRED -continued EMBODIMENTS (III) A positive-negative diffusion transfer film unit which may be utilized in the method of the invention com prises a transparent support such as, for example, an organic polymeric material, carrying a photosensitive silver halide emulsion layer and an image-receiving ( ) S NN layer. In a preferred embodiment the film unit includes CH3 a multicolor additive screen, preferably a three color O screen such as one having alternating red, blue and \ / green lines. These film units can be fabricated by tech (IV) niques which are known in the art. A technique for fabricating a transparent support carrying a pattern of alternating, microscopically fine, red, blue and green 15 ("Ya lines is described in U.S. Pat. No. 3,284,208. Deposition of a silver halide emulsion layer and an image receiving C ) layer can be effected by any of many techniques. The silver halide may be a silver chloride, iodide, bromide, iodobromide, chlorobromide, etc. The binder for the 20 halide, though usually gelatin, may be any suitable poly (V) mer such as polyvinyl alcohol, polyvinyl pyrrolidone and their copolymers. The image receiving layer prefer ably includes certain materials the presence of which during the transfer process has a desirable effect upon 25 S N the amount and character of the silver precipitated on YoHs the layer. Specific materials of this type are known in S u the art. The film unit optionally may include other lay ers such as an antihalation layer as will be apparent to Specific suitable acyclic silver complexing agents are those skilled in the art. 30 As mentioned previously, in operation of the method represented by the following structural formulas: the exposed silver halide emulsion layer is developed by being contacted with a photographic processing com CH3 (VI) position which includes a silver halide developing agent and a silver complexing agent having the properties 35 described above. There is thus formed in the unexposed and undeveloped areas of the silver halide emulsion CH3 (VII) layer a soluble and diffusible complex of the silver com plexing agent and silver. This imagewise pattern of the complex is transferred to the image-receiving layer which is in superposed relationship with the silver hal ide emulsion layer and there is provided in the former Compound (I) is disclosed in Tetrahedron Letters, the desired positive silver transfer image. Pelissard and Louis, 45, pp. 4589-4592 (1972). The other The silver complexing agents which have the speci compounds are per se novel compounds and are dis fied physical properties include cyclic and acyclic com 45 closed and claimed in applicants' copending applica pounds. Specific suitable cyclic crown ether silver com tions Ser. No. 080,440 and Ser. No. 080,350, both filed plexing agents are represented by the following struc on even date herewith. tural formulas: Compound (I) may be synthesized according to the method described in the above-cited literature article. (I) 50 Alternatively, the novel 15 crown -5 ligands may be synthesized by reacting N,N'-dimethyl-N,N'-bis(2-mer captoethyl)ethylenediamine for its preparation see J.A- mer.Chem.Soc., 98, 6951 (1976) with (CICH2CH2) X (where X may be O, S, NH or N-Me) in a suspension 55 of sodium hydride in dimethylformamide. Compounds (VI) and (VII) can be made by reacting the ethylenedi amine compound with ethylene oxide and methyl io dide respectively. The desired ligands can be separated (II) 60 from the crude reaction products by first treating a methanol solution of the roduct with silver thiocyanate to form a 1:1 ligand-silver thiocyanate complex which preferentially crystallizes from solution while the impu rities remain in the filtrate. Recrystallization of the com 65 plex followed by the precipitation of silver as silver ( ) sulfide with hydrogen sulfide and liberation of the free ligand by passing an aqueous solution of the resulting thiocyanic acid complex through an anion exchange 4,267,254 5 6 column provides essentially pure samples of the ligands. Alternatively, purification can be effected by chroma agent, preferably an organic developing agent. Exam tography of the crude product mixture on silica gel, a ples of developing agents that may be used include more time consuming procedure. hydroquinone and substituted hydroquinones such as As mentioned previously, for the silver complexing tertiary butyl hydroquinone, 2,5-dimethyl hydroqui agents utilized in the method of the invention, the log of none, ethoxyhydroquinone and chlorohydroquinone; the stability constant (3) for a 1:1 complex of the com pyrogallol and catechols such as catechol, 4-phenyl plexing agent with silver is at least about 10.5. The log catechol and tertiary butyl catechol; aminophenols such of the stability constant (3) for each of the specific as 2,4,6-triaminoorthocresol, 1,4-diaminobenzenes such preferred silver complexing agents employed in the 10 method is shown in Table I. The stability constants as p-phenylenediamine; 1,2,4-triamino-benzene, 4 were determined by potentiometry, i.e., by titrating the amino-2-methyl-N-N-diethylaniline, ascorbic acid and ligand with a standardized solution of silver perchlorate its derivates such as ascorbic acid, isoascorbic acid and in mildly alkaline, and constant ionic strength medium 5,6-isopropylidene ascorbic acid; other enediols such as (0.05 M NaOH, 0.10 M. NaClO4). All solutions and ti 15 tetramethyl reductic acid; and hydroxylamines such as trants were prepared carbonate free and with an ionic N,N-di-(2-ethoxyethyl) hydroxylamine and N,N-di-(2- strength of 0.1 M(NaClO4) except when the perchlorate methoxyethoxyethyl) hydroxylamine. salt of the complex was found to be insoluble. In that eventuality perchlorate was omitted from the system. It should be noted that the relative proportions of the An argon atmosphere was used throughout. The indi silver complexing agent(s) and the other components of cating electrode was a silver specific ion type used in 20 the processing composition may be varied to suit the conjunction with a sleeve type double junction Ag requirements of any particular film unit and processing /AgCl reference electrode. conditions employed according to the present method. TABLE I In addition, it will be apparent that where desirable Compound log 25 there may be included in the processing composition I 11.37 - 0 other components as are commonly utilized in the pho I 11.84 . .01 tographic art, such as antifoggants, etc. III 2.30.01 In diffusion transfer processes, the processing compo V& 1198 - 02 sition, if it is to be applied to the emulsion by being V 11.84 - 02 30 V 10.91 - 01 spread thereon in a thin layer, usually also includes a VII 0.97 - 0 viscosity imparting reagent. Thus the processing com *No perchlorate was added. position employed in the method may comprise, for The photographic processing composition which is example, one or more of the silver complexing agents utilized according to the method of the invention may 35 having the specified properties, one or more of the include one or more of the silver complexing agents conventional developing agents such as those described having the properties specified above. The total amount above, an alkali such as sodium hydroxide or potassium of silver complexing agent(s) present in the processing hydroxide and a viscosity imparting reagent such as a composition in any specific instance may vary depend high molecular weight polymer, for example, sodium ing upon factors such as, for example, the particular 40 carboxymethyl cellulose or hydroxyethyl cellulose. materials which comprise the respective elements of the In one embodiment the processing composition is film unit and the particular processing conditions which are employed. Generally, the total amount of the silver applied in a uniformly thin layer between the super complexing agent(s) present in the processing composi posed surfaces of the silver halide emulsion layer and tion is in the range of from about 1 percent to about 10 45 the image receiving layer by advancing the film unit percent by weight of the composition. between a pair of pressure applying rollers. It has also been found through laboratory experimen As noted previously, in diffusion transfer film units tation that the silver complexing agents of the type the negative component which comprises at least one described above can be used together with silver com photosensitive silver halide emulsion layer and the posi plexing agents which do not possess the specified melt 50 tive component which comprises an image receiving ing point and silver complexing ability and continue to provide the advantageous results obtained according to layer may be in separate sheet-like elements which are the present method. It has been shown that silver com brought together during processing and thereafter re plexing agents which do not possess the specified prop tained together as a permanent laminate according to erties and which, when used alone in the amounts neces 55 the present method or the negative and positive compo sary for processing quickly form crystals in the trans nents may be initially provided in the same integral parency, can be combined with the silver complexing element. In the latter type of film unit, typically, the agents having the specified physical properties, utilized image receiving layer is coated upon a support and the under the same processing conditions and yet provide photosensitive layer is deposited upon the surface of the transparencies wherein crystal formation is substan 60 image-receiving layer. tially or completely eliminated. It has been found that molar equivalent amounts of the respective types of The invention will now be described further in detail silver complexing agents can be used together and pro with respect to specific preferred embodiments by way vide the advantageous results obtained according to the of examples, it being understood that these are illustra invention. 65 tive only and the invention is not intended to be limited The photographic processing composition, in addi to the materials, conditions, process parameters, etc., tion to the silver complexing agent(s) of the requisite which are recited therein. All parts and percentages are type, comprises a suitable silver halide developing by weight unless otherwise indicated. 4,267,254 7 8 dissolving the crystals in excess solvent at 40 C. and EXAMPLE I then concentrating to about one-half the initial volume. Preparation of The crystals were then dried under high vacuum. A N,N'-dimethyl-N,N'-bis(2-mercaptoethyl)ethylene total of 8.5g of 1:1 compound (II)-silver thiocyanate diamine 5 complex, m.p. 147-149 C. was recovered. Recrystalli A 250 ml three-neck flask, equipped with a magnetic zation of a small sample of this material gave essentially stirrer, addition funnel, thermometer and argon inlet colorless crystals, m.p. 149-150° C. C13H26N3OS.Ag was charged with a solution of 18.3 g (0.208 mol) of requires 35.13% C, 5.89% H, 9.46% N, 21.64% S and N,N'-methylethylenediamine in 70 ml of benzene. A 24.27% Ag. Elemental analysis of this material gave solution of 25.1 g (0.417 mol) of ethylene sulfide in 100 35.03% C, 5.91% H, 9.50% N, 21.60% S and 24.43% ml of benzene was added with stirring to the solution in Ag. Also NMR spectral data were consistent with a 1:1 the flask under argon while maintaining the tempera compound (II)-silver thiocyanate complex stoichiom ture of the solution in the flask at 50-55 C. The result etry. ing clear solution was allowed to remain overnight at 8.3 g (18.7 moles) of the complex were dissolved in ambient temperature, washed with two 5 ml portions of 100 ml of a 70:30 (vol/vol) mixture of dichloromethane water and dried over magnesium sulfate. The solvent and ether and treated with hydrogen sulfide gas to pre was removed under reduced pressure and 39.9 g. (97% cipitate silver as silver sulfide. Bubbling of hydrogen yield) of a colorless oil was obtained. sulfide was continued until an aliquot of the supernatant The material is susceptible to air oxidation and there solution gave no precipate with hydrogen sulfide. The fore further purification was not carried out. The mate-20 mixture was then stirred for about 15 minutes, filtered rial can be stored up to a week under argon in a freezer through Celite 542 and the filtrate was concentrated to without any significant deterioration. Since the com a thick colorless syrup, presumably a thiocyanic acid pound has an extremely unpleasant odor and can cause complex of ligand (II). The free ligand, compound (II), severe skin allergy careful handling is necessary. 25 was liberated from this material by the following alter Preparation of Compound (II) native procedures: (A) A column of a strongly basic, quaternary ammo A three neck one liter flask equipped with an over nium (polystyrene) type, anion exchange resin (Amber head stirrer, addition funnel and argon inlet, and an oil bath was charged with 14.5 g. of a 50% sodium hydride lite IRA-400) was prepared in carbonate-free water, dispersion in oil (0.26 mol of NaH). Most of the oil was 30 washed with dilute sodium hydroxide and then removed by repeated washings with petroleum ether throughly with water until the eluent was not basic. An carrier out under argon. In each washing about 15-20 aqueous solution of the colorless syrup was passed ml of petroleum ether were added to the dispersion, the through the column and washing with carbonate-free dispersion stirred briefly and allowed to settle and su water was continued until most of the material had been pernatant liquid removed with a syringe. 520 ml of 35 eluted. The combined washings were concentrated spectrograde dimethylformamide were then introduced under reduced pressure. The residual syrup was dis into the dispersion and the reaction flask was heated solved in absolute ethanol, filtered through Celite 542 with the oil bath maintained at about 95 C. When the and the filtrate concentrated to provide about 5 g. of internal temperature of the flask reached about 75 C. compound (II) as a clear colorless syrup. The sample there was begun the dropwise addition, with vigorous 40 was dried at 50 C. by pumping under high vacuum. stirring, of a mixture of 27.08 g. (0.13 mole) of N,N'- (B) Alternatively, the aqueous solution of the thiocy dimethyl-N,N'-bis(2-mercaptoethyl) ethylenediamine anic acid complex was treated with a stoichiometric and 18.6 g. (0.13 mole) of bis-2-chloroethylether in 40 amount of a 10% aqueous tetramethylammonium hy ml dimethylformamide. Addition of the mixture was droxide solution and extracted with ethylacetate or completed in 2.5 hours with the temperature maintained 45 dichloromethane. The organic layer was washed with between 80-85 C. throughout the addition of the mix water and dried over anhydrous sodium sulfate. Re ture and for about 16 hours thereafter. Most of the moval of the solvent gave compound (II) as a colorless solvent was removed in vacuo with the bath tempera Syrup. ture at about 70-75° C. The resulting thick light brown C12H26N2S2O requires 51.75% C, 9.41% H, 10.06% oil was dissolved in 300 ml of ethylacetate, washed with 50 N,and 23.03% S. Elemental analysis gave 51.74% C, three 20 ml portions of water and dried over magnesium 9.39% H, 10.02% N and 22.84% S. sulfate. Removal of the solvent under reduced pressure A film unit was prepared as follows: the light-sensi gave 34 g. of a light brown syrup. Analysis showed this tive element comprised a transparent polyester film base to be a complex mixture of products. carrying on one surface an additive color screen of A solution of 18 g. of the crude product in 200 ml of 55 approximately 1500 triplets per inch of red, blue and methanol was formed and to it there were added 10.9 g, green filter screen elements in repetitive side by side of silver thiocyanate in portions. Toward the end of the relationship; a composite barrier structure made up of silver thiocyanate addition dissolution of the silver salt an approximately 0.7 micron thick layer of polyvinyli became slow and a sticky material separated from solu dene chloride coated from a solvent, an approximately tion. The mixture was stirred for about 15 minutes after 60 1.0 micron thick layer of polyvinylidene chloride which the soluble portion was removed, diluted with coated from water emulsion and an approximately 0.3 100 ml of methanol and filtered through Celite 542 (a micron thick layer of polyvinyl formal; a nucleating diatomaceous earth material available from Johns Man layer comprising 0.23 mg/ft.2 of palladium nuclei (as ville Co.). The filtrate was concentrated to 120 ml under metal), ) 0.29 mg/ft.2 of gelatin, 0.35 mg/ft.2 of tin (as reduced pressure and stored for two days in a refrigera- 65 metal) and 0.47 mg/ft.2 of total chloride (associated tor. Light yellow crystals deposited during storage and with Pd and Sn); an interlayer of 1.94 mgs./ft.2 of gela these were collected, washed with methanol and recrys tin, and 0.194 mg/ft2 of alkyl phenoxy polyoxyethyl tailized from methanol twice at low temperature by first ene glycol; a hardened gelatino silver iodobromo emul 4,267,254 10 sion coated at a coverage of about 85 mgs./ft.2 of silver, ally immediately after processing and 17 days later, was 85 mgs./ft of gelatin, 7.5 mgs./ft.2 of propylene glycol found to be substantially free of crystals. alginate, 0.41 mg/ft.2 of chrome alum (coverage as K2Cr(SO4)2; and 0.61 mg/ft.2 of alkyl phenol polygly EXAMPLE II col ether (average 9.5 mols ethylene oxide) surfactant; and an antihalo top coat of 300 mgs./ft.2 of gelatin, 175 Preparation of Compound (III) mgs./ft.2 of Dow 620 carboxylated styrene butadiene To a suspension of 0.24 g. of a 50% sodium hydride latex, 22 mgs./ft.2 of propylene glycol alginate, 1.2 dispersion in oil (which had previously been washed mgs./ft.2 of dioctyl ester of sodium succinic acid, 5.6 free of oil with petroleum ether) in 15 ml of dimethyl mgs./ft.2 of pyridinium bis-1,501,3-diethyl-2-thiol-5-bar 10 formamide was added 0.95 g. of mechlorethamine hy bituric acid) pentamethine oxanol, 7.0 mgs./ft.2 of 4-(2- drochloride. To the resulting free amine were added chloro-4-dimethylamino benzaldehyde)-1-(p-phenyl 1.05 g. of N,N'-dimethyl-N,N'-bis(2-mercaptoethyl) carboxylic acid)-3-methyl pyrazolone-5 and 5.0 ethylenediamine in 5 ml of dimethylformamide. mgs./ft.2 of benzimidazole-2-thiol gold Aul complex To a separate three neck flask there was added 0.5g. (as gold). 15 of a 50% sodium hydride dispersion in oil and this was The cover sheet comprised a 4 mil thick polyester washed free of oil with petroleum ether under argon. support having a thin coating on one surface to prepare To this were added 50 ml of dimethylformamide and the support for coating. Coated on the support in the the suspension was heated to 80°-90° C. The mixture of following order were: the two reactants prepared above was then added drop (A) An acid providing layer formed by combining 60 20 wise with vigorous stirring over a period of about 25 parts by volume of a 30% solution of the half butyl ester minutes and stirring was continued at that temperature of ethylene maleic anhydride in methyl ethyl ketone overnight. The solvent was then removed under re and 40 parts by volume of a solution of 5.7% Butvar duced pressure, the residue taken up in 25 ml of ethyl B-72 (available from Monsanto), 63.3% ethyl acetate and 31%. n-butanol and coating the mixture on the sup acetate, washed twice with 5 ml portions of water and port to provide a dry coverage of about 2.45 gms/ft2; 25 dried over sodium sulfate. Removal of the solvent gave and 1.4 g of a slightly colored syrup. 13C NMR and thin (B) A gelatin layer formed by coating a water solu layer chromatography on silica gel using a 50:50 (vol/- tion containing 10% deionized gelatin, and 0.05% vol) mixture of ethylacetate-hexane showed this to be a Emulphor ON-870 (available from Antara Chemical mixture of products. Purification by column chroma Co.) to provide a dry coverage of about 1 gm/ft2. 30 tography on silica gel gave 0.5 g. of compound (III) The film unit as identified above was exposed to a characterized by 13C NMR and mass spectrum step wedge and processed while being retained intact, (m/e=291, parent ion and 292, P-- 1). by spreading a layer of a processing composition less A stirred solution of 116 mg of compound (III) in 5 than about 3 mils thick between the light-sensitive ele ml methanol was treated with 66.4 mg of silver thiocya ment and cover sheet. The processing composition was 35 nate. After 10 minutes the mixture was filtered to re prepared by adding 0.5 ml of compound (II) to 10 ml of move traces of suspended material and the solvent re the following formulation: moved under reduced pressure to give a white crystal line solid, m.p. 160-162C. The product was crystal lized from methanol by storing for several days in a Water 82.36 g. 40 Sodium hydroxide 7.265 g. refrigerator. Needle-like crystals formed and these were Hydroxyethyl cellulose 2.811 g. collected by filtration and washed to give colorless Sodium sulfite 2.54 g. needles, m.p. 164-165 C. Tetramethyl reductic acid 3.17 g. C14H29NAS3.AG requires 36.75% C, 6.39% H, Dodecyl-N,N-dipyridinium 1.78 g. 12.25% N, 21.03% S and 23.58% Ag. Elemental analy dibromide 45 4-aminopyrzaolo (3,4-d) 0.016 g. sis of the product gave 36.70% C, 6.35% H, 12.29% N, pyrimidine 21.03%. S and 23.74% Ag. 5-bromo-6-methyl-4- 0.016 g. azabenzimidazole EXAMPLE III Thiazololidine-2-thione 0.035 g. Preparation of Compound (IV) 50 After an imbibition period of about one minute, the In a two-neck flask 0.24 g. of a 50% sodium hydride resultant image was examined visually and found to be dispersion in oil was washed free of oil with petroleum substantially free of crystals. After a period of 17 days, ether under argon atmosphere and then 15 ml of di the image was again examined visually and again found methylformamide were introduced with a syringe. The to be substantially free of crystals. The transparency 55 suspension was stirred for 5 minutes and 0.89 g. of bis was stored under ambient conditions during the interim. chloroethylamine hydrochloride was added with stir An identical film unit was processed in the same man ring followed by the addition of 1.5 g. of N,N'-dimeth ner with the exception that the processing composition yl-N,N'bis(2-mercaptoethyl) ethylenediamine. included 0.4061 g of a 2-alkylthioether-4,6-dihydrox In a separate 3-neck flask equipped with an addition ypyrimidine complexing agent (approximate molar 60 funnel there was added 0.5g of a 50% sodium hydride equivalent of 0.5 ml of compound II) in place of com dispersion in oil which was then washed free of oil with pound II. Crystals were visually apparent in the trans petroleum ether under argon. Then 45 ml of dimethyl parency within one day after processing. formamide were added and the suspension was stirred Another film unit was processed in the same manner at a temperature of 80°-90° C. To the suspension was described above with the exception that the processing 65 added dropwise over a period of about 1.5 hours the composition was made up of equal volumes of each of reactant mixture described above. Stirring was contin the processing compositions previously described in ued overnight at that temperature and then for an addi this example. The transparency, when examined visu tional period at room temperature. Most of the solvent 4,267,254 11 12 was removed under reduced pressure and the residue mass spectrum showed a weak m/e at 296 for the parent was taken up in 30 ml ethyl acetate, washed twice with ion with a strong P-4-1 at 297. 5 ml portions of water and dried over sodium sulfate. To assure the removal of any last traces of impurities, Removal of the solvent gave a clear light brown syrup. a small sample of the ligand was chromatographed on The product was purified by column chromatogra silica gel using ethyl acetate-methanol mixture or di phy on silica gel using an ethyl acetate-ethanol mixture chloromethane-methanol mixture as the eluent. After for elution. NMR spectra of the product were consis chromatographic separation the product was crystal tent with compound (IV). lized from ethyl acetate-petroleum ether mixture at EXAMPLE IV -15 C. to furnish pure ligand as colorless needle-like O crystals, m.p. 44-45 C. C12H28N2S2O2 requires Preparation of Compound V 48.61% C, 9.52% H, 9.45% N, 21.63% S, and 10.79% In a 250 ml three neck flask equipped with an addition O. Elemental analysis gave 48.75% C, 9.60% H, 9.20% funnel, reflux condenser and a serum cap there were N and 21.53% S. NMR and mass spectral data were added 1.01 g of 50% sodium hydride dispersion in oil. consistent with the desired ligand. The dispersion was washed free of oil by repeated treat 15 A film unit was prepared as follows: the light-sensi ments of petroleum ether under argon. Most of the tive element comprised a transparent polyester film base petroleum ether was removed with a syringe and the carrying on one surface an additive color screen of last traces removed by blowing with argon. Dimethyl approximately 1000 triplets per inch of red, blue and formamide (70 ml) was added and the suspension heated green filter screen elements in repetitive side by side to 70-80 C. To the stirred suspension there was slowly 20 relationship; an approximately 4 micron thick polyvi added dropwise over a period of 2 hours at a tempera ture of 85°-90° C., a mixture of 2.1 g of N,N'-dimethyl nylidene chloride barrier layer; a nucleating layer com N,N'-bis(2-mercaptoethyl) ethylenediamine and 1.58 g. prising 0.23 mg/ft2 of palladium nuclei (as metal), 0.29 of bis-2-chloroethylsulfide in 15 ml dimethylformamide. mg/ft2 of gelatin, 0.35 mg/ft2 of tin (as metal) and 0.47 Stirring was continued overnight at 85°-90° C. after 25 mg/ft2 of total chloride (associated with Pd and Sn); an which the solvent was removed under reduced pres interlayer of 2.21 mgs/ft2 of deacetylated chitin, 0.645 sure. The residue was extracted with ethyl acetate, mg/ft2 of copper acetate (dihydrate), 0.178 mg/ft2 of washed three times with 5 ml portions of water and sodium acetate and 0.194 mg/ft2 of alkyl phenoxy dried over magnesium sulfate. The residue was concen polyoxy ethylene glycol; a hardened gelatino silver trated to give a brown syrup and the last traces of sol 30 iodobromo emulsion coated at a coverage of about 90 vent removed under reduced pressure. The product was mgs/ft2 of silver, 120 mgs/ft2 of gelatin, 53 mgs/ft2 of purified by chromatography with silica gel using ethyl Dow-620 carboxylated styrene butadiene latex and 4.83 acetate as the eluent to furnish compound V as a pale mgs/ft2 of dioctyl ester of sodium succinic acid (a sur colored syrup which solidified under refrigeration. factant); and an antihalo topcoat of 300 mgs/ft2 of gela C12H26N2S3 requires 48.93% C, 8.89% H, 9.51% N 35 tin, 175 mgs/ft2 of Dow-620 carboxylated styrene buta and 32.66% S. Elemental analysis of the product gave diene latex, 0.3 mg/ft2 of dioctyl ester of sodium suc 48.88% C, 8.80% H, 9.38% N and 32.51% S. cinic acid, 5.2 mg/ft2 of pyridinium-bis-1,5(1,3-diethyl 2-thiol-5-barbituric acid) pentamethine oxanol, 7.0 EXAMPLE V mgs/ft2 of 4-(2-chloro-4-dimethylamino benzaldehyde)- Preparation of Compound (VI) 40 1-(p-phenylcarboxylic acid)-3-methyl pyrazolone-5 and A 500 ml hydrogenation bottle placed in a 5 C. cool 4.9 mgs/ft2 of benzimidazole-2-thiol gold Aull com ing bath was charged with 6.3 g (30 m mol) of freshly plex (as gold). The cover sheet was the same as de prepared N,N'-dimethyl-N,N'-bis(2-mercaptoethyl) scribed in Example I. ethylenediamine in 35 ml of carbonate-free water. To Film units as described above were processed in the the resulting aqueous suspension there was added rap 45 same manner described in Example I. The processing idly, with vigorous stirring, 3 ml (60 mmol) of ethylene compositions were prepared by adding 0.08725 g, 0.349 oxide. The bottle was stoppered tightly and the con g and 0.689 g, respectively, of compound VI to 10 ml of tents allowed to stir for about 8 hours at 5 C. and then the formulation described in Example I. These amounts for another 8 hours at 25°C. The NMR spectrum of the of compound VI represent approximately , , ; and 1 resulting aqueous solution showed six major lines ex 50 molar equivalent, respectively, of the amount of silver pected for the desired ligand (compound (VI) accompa solvent used for comparative purposes in Example I. nied by 15-20% of unidentified impurities. Removal of The transparencies were examined visually and found the solvent under reduced pressure gave a colorless to be substantially free of crystals fifteen days after syrup which was dissolved in 75 ml of dichloromethane, processing. The transparencies were stored under ambi washed with two 5 ml portions of water, dried over 55 ent conditions during the interim. magnesium sulfate and concentrated to provide 6.5 g of For purposes of comparison an identical film unit was a syrupy product. This product solidified upon being processed in the same manner with the exception that stored overnight in a refrigerator. Thin-layer chroma the processing composition included 0.4061 g of a 2 tography on silica gel (in methanol) showed one major alkylthioether-4,6-dihydroxypyrimidine complexing spot accompanied by traces of more polar impurities. 60 agent in place of compound VI. Crystals were visually For further purification a 5.5 g sample of the crude apparent in the transparency within one day after pro material was stirred with 100 ml of ether until a fine, cessing. uniform suspension was formed. The suspension was Two identical film units were processed in a similar kept at 0° C. for about 2 hours in an ice bath, the solid manner with the exception that the processing composi filtered, washed with four 10 ml portions of ether and 65 tions were made up of the processing composition used dried in vacuo to give 3.7 g of the ligand (compound in the comparative test mixed with, in the first instance, (VI)-a colorless solid m.p. 43-44 C. 13C and "H NMR an equal volume of the processing composition contain spectra were consistent with the assigned structure. The ing 0.08725 g of compound VI and, in the second in 4,267,254 13 14 stance, an equal volume of the processing composition tracts were washed with water and dried over magne containing 0.1745 g of compound VI. When examined sium sulfate. The solvent was removed under reduced visually, fifteen days after processing, no crystals were pressure, and there were obtained 2.45 g of the ligand apparent in the transparencies. (compound VII) as a clear, thin liquid. NMR spectra EXAMPLE VI were consistent with the desired ligand. Film units as described in Example V were processed Preparation of Compound VII in a similar manner with the exception that the process To a 250 ml, three-neck flask equipped with a stirring ing compositions were prepared by adding 0.054.05 g, bar, addition funnel, argon inlet and a rubber septum 0.108 g and 1.081 g of compound VII, respectively, to were added 3.98 g of 50% sodium hydride-oil disper 10 10 ml of the formulation described in Example I. The sion. Most of the oil was removed by washing the dis latter two processing compositions were cloudy indi persion with three 20-ml portions of petroleum ether cating saturation. These amounts of compound VII under argon. 50 ml of dry tetrahydrofuran (99.9%) correspond to approximately 1/10, 1/5 and 2 molar were then introduced into the dispersion from a syringe equivalent(s), respectively, of the amount of the silver followed by a dropwise addition, with stirring, of 8.5g 15 solvent used for comparative testing in the previous (40 m mol) of N,N'-dimethyl-N,N'-bis (2-mercapto examples. ethyl) ethylenediamine at a rate slow enough to keep When examined visually ten days after processing the frothing under control. The contents of the flask were transparencies did not have any apparent crystals. The allowed to stir for an additional 15 minutes and then transparencies were stored under ambient conditions treated with a solution of 10.96 g (80 m mol) methyl 20 during the interim. - iodide in 7 ml tetrahydrofuran, added dropwise with For purposes of comparison an identical film unit was vigorous stirring over a period of about 30 minutes. processed in the same manner with the exception that Throughout the addition, the temperature was main the processing composition included 0.4061 g of a 2 tained below 30° C. by occasional cooling in an ice bath. alkylthioether-4,6-dihydroxypyrimidine complexing The resulting reaction mixture was allowed to stir at 25 agent in place of compound VII. Crystals were visually ambient temperature for about 14 hours. Excess sodium apparent in the transparency within one day after pro hydride was then destroyed with 5 ml of cold water and cessing. the solvent removed under reduced pressure. The residue was taken up in 50 ml of ether, stirred for An identical film unit was processed with a process about 5 minutes and filtered to remove the suspended 30 ing composition made up of equal volumes of the pro solids which were then washed with three 10 ml por cessing composition used for comparative purposes and tions of ether. The combined ether filtrate and washings the processing composition containing 0.054.05 g of were treated with three 5 ml portions of water to re compound VII. No crystals were visually apparent in move any inorganic salts and dried over magnesium the transparency ten days after processing. The trans sulfate. Removal of solvent under reduced pressure 35 parency was stored under ambient conditions during gave 7.9 g of an essentially colorless thin liquid. Thin the intermin. layer chromatography on silica gel with methanol Although the invention has been described in detail showed one major spot accompanied by some minor with respect to various embodiments thereof, these are polar impurities. intended to be illustrative only and not limiting of the To a solution of 7.5g of the product in 50 ml of meth 40 invention but rather those skilled in the art will recog anol were added 5.1 g of silver thiocyanate in small nize that modifications and variations may be made portions with vigorous stirring. Initially, the silver salt therein which are within the spirit of the invention and appeared to go into solution quite rapidly; but toward the scope of the appended claims. the end of the addition, the rate of dissolution slowed What is claimed is: considerably. The mixture was allowed to stir for about 45 1. A diffusion transfer photographic process compris 20 minutes after addition of the silver thiocyanate, di ing the steps of: luted with 100 ml of methanol and filtered through (a) exposing a positive-negative diffusion transfer film Celite 542 to remove insoluble material. The filtrate was unit comprising a support carrying an additive concentrated under reduced pressure to about 30 ml and color screen, a photosensitive silver halide emul stored overnight in a refrigerator. Crystals developed 50 sion layer and a silver precipitating layer through and were collected and recrystallized twice from meth said additive color screen in imagewise fashion; anol to provide 4.7 g of nearly colorless solid m.p. (b) developing the exposed silver halide emulsion 106°-107 C. C11H24N3S3. Ag requires 32.83%C, layer by contacting it with a photographic process 6.01%H, 10.44% N, 23.90%S and 26.81% Ag. Elemental ing composition comprising an aqueous alkaline analysis gave 32.88%C, 5.89%H, 10.42%N, 23.72%S 55 solution including a silver halide developing agent and 26.83% Ag. NMR spectra were consistent with the and a silver complexing agent, said silver complex 1:1 compound VII-silver thiocyanate complex. ing agent being stable in an alkaline environment, 4.5g of the complex were then dissolved in 50 ml of having a melting point less than about 50 C. and 60:40 (vol/vol) dichloromethane-ether mixture. The wherein the log of the stability constant (3) for a solution was cooled in an ice bath and treated with 60 1:1 complex of said silver complexing agent with hydrogen sulfide gas to precipitate silver as silver sul silver is at least 10.5, wherein a silver complex fide. Following complete precipitation stirring was which is soluble in said alkaline solution is formed carried out for 15 minutes. The contents were then between undeveloped silver halide and said silver filtered through Celite 542 and the filtrate was concen complexing agent; and trated under reduced pressure to give a clear liquid. The 65 (c) transferring said silver complex to said silver pre liquid was treated with a stoichiometric amount of cipitating layer and forming a silver image therein, aqueous tetramethylammonium hydroxide and the wherein said process is carried out while retaining product was extracted with dichloromethane. The ex said film unit intact and without washing the unit. 4,267,254 15 16 2. The process as defined in claim 1 wherein said silver precipitating layer is located between said addi -continued tive color screen and said silver halide emulsion layer. 3. The process as defined in claim 1 wherein said processing composition includes up to about 10 percent by weight of said silver complexing agent. 4. The process as defined in claim 1 wherein said CH3 additive color screen comprises red, blue and green filter screen elements in repetitive side by side relation 10 and ship. (c) transferring said silver complex to said silver pre 5. The process as defined in claim 1 wherein said cipitating layer and forming a silver image therein, processing composition includes in addition to said wherein said process is carried out while retaining silver complexing agent a second silver complexing agent which does not possess all of the recited proper 15 said film unit intact and without washing the unit. ties of said silver complexing agent. 9. The process as defined in claim 8 wherein said 6. The process as defined in claim 5 wherein said silver complexing agent is a compound represented by processing composition includes molar equivalent 20 the formula amounts of said silver complexing agent and said second silver complexing agent. 7. The process as defined in claim 1 wherein said complexing agent has a melting point of about 25 C. or less. 25 8. A diffusion transfer photographic process compris (^^). ing the steps of (a) exposing a positive-negative diffusion transfer film C. unit comprising a support carrying an additive 30 color screen, a photosensitive silver halide emul \ / sion layer and a silver precipitating layer through said additive color screen in imagewise fashion; 10. The process as defined in claim 8 wherein said (b) developing the exposed silver halide emulsion 35 silver complexing agent is a compound represented by layer by contacting it with a photographic process ing composition comprising an aqueous alkaline the formula solution including a silver halide developing agent and a silver complexing agent represented by a formula selected from the group consisting of 40 / S ^ CH3

?y (?ya 45 S N5 V /CH

C, PC, 11. The process as defined in claim 8 wherein said \ / \ / " 50 silver complexing agent is a compound represented by the formula

55

H3C CH3 S /. ^ C, 2CH, C, CH3 NN N1 60 C D CH3 S N V / SCHs (CH2)2 S N CH CH3 65 12. The process as defined in claim 8 wherein said S v silver complexing agent is a compound represented by and the formula 4,267,254 17 18 14. The process as defined in claim 8 wherein said silver complexing agent is a compound represented by the formula S r/ N CH3 5 H3C-S-(CH2)2-N CH3 (CH2)2 \ / CHs 10 CH3 15. The process as defined in claim 8 wherein said 13. The process as defined in claim 8 wherein said silver complexing agent is a compound represented by silver complexing agent is a compound represented by 15 the formula the formula

N 1. CH3 A. CH3 20 S N (CH2)2 V v- a. CH3 CH3 25 sk k is k sk

30

35

45

50

55

60

65