US 2857276 A
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PHOTOGRAPHIC PROCESSES AND COMPOSI- TIONS USEFUL THEREIN No Drawing. Application November 23, 1954 Serial No. 470,802
4 Claims. (Cl. 96-29) Lexington, Mass., assignors to Cambridge, Mass., a corporation The present invention relates to photography and, more particularly, to diffusion transfer-reversal processes and compositions useful therein.
-In a typical diffusion transfer-reversal process, an aqueous solution of a silver halide developer and a silver halide solvent is applied to a silver halide stratum and a silver-receptive stratum which are in superposed relation. The developer and solvent cooperate to reduce exposed silver halide to silver, to react with unreduced silver halide to form a Water-soluble, complex silver salt, and to transfer the salt to the silver-receptive stratum where it is reduced to silver.
Developers and solvents, which in the past have been found to cooperate satisfactorily in diffusion transferreversal processes, have suffered various shortcomings. For example, certain developers, e. g., hydroquinone, if unexhausted, react with atmospheric oxygen to form a colored product which stains the highlights of the image and, if exhausted, oxidize silver to cause the image to fade. Also, certain complexing agents, e. g., ammonia, are often too weak to be fully effective in the production of transfer images; others, e. g., sodium thiosulfate, leave on the transfer image a harmful sulfur residue; and still others, e. g., sodium cyanide, are often impractical because of their dangerous toxicity.
The present invention contemplates a novel solution of the foregoing type which contains effective components and leaves a harmless residue. Essentially, this solution includes a cyclic imide and a hydroxylamine. Preferably, it includes also a nitrogenous base, e. g., an amine, other than a hydroxylamine. Of these components, it is believed that the cyclic imide and the hydroxylamine and/or other nitrogenous base cooperate to perform a complexing function, and the hydroxylamine itself performs a developing function. It has been discovered that cyclic imides and nitrogenous bases which are not effective as complexing agents independently are very effective to gether. The coaction of these complexing agents is the subject of copending patent application Serial No. 378,684, filed September 4, 1953, in the name of Edwin H. Land et al. It has been discovered also that hydroxylamines, ordinarily weak developers, are effective in diffusion transfer-reversal processes and, particularly, in diffusion transfer-reversal processes in which silver complexing is accomplished in the foregoing way. The striking coaction of cyclic imides and hydroxylamines is fortunate because: when exhausted, they do not react with silver to deteriorate the image; they can leave no sulfur residue since they are sulfur free; they may be readily handled since they are relatively nontoxic; and they do not stain the image since their reaction products are pale or colorless.
Accordingly, objects of the present invention are: to provide, as a novel composition of matter, an alkaline aqueous solution comprising at least one member of the class consisting of the cyclic imides and at least one member of the class consisting of the nitrogenous bases, at least one member of the former class and at least one United States Patent with respect to each of Although the foregoing formula is in keto form,
class, together, being operative to form water-soluble, complex silver salts, at least one member of the latter class being a hydroxylamine operative as a silver-reducing agent; and to provide diffusion transfer-reversal processes employing such a composition. 4
Other objects of the invention will in part be obvious and will in part appear hereinafter.
The invention accordingly comprises the several steps and the relation and order of one or more of such steps the others, and the composition possessing the features, properties and the relation of elements which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.
For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description.
Preferred cyclic imides to be employed, in accordance with the present invention, are characterized by the following general formula:
member of the latter (1) atoms of a series completing a cyclic imide nucleus consisting of from 5 to 6 atoms of which from 1 to 3 are nitrogen and the remainder are carbon, and (2) components branching from the atoms of the series, these components being selected from the class consisting of hydrogen atoms, amino radicals, aliphatic radicals containing from 1 to 4 carbon atoms, halogen atoms, keto oxygen atoms and aromatic radicals, at most one of these components being one of the halogen atoms, keto oxygen atoms and aromatic radicals.
it is intended to encompass the enolic modifications of compounds within its scope.
Typical preferred cyclic imides, corresponding to the foregoing general formula, are triazines, barbiturates, uracils, urazoles, hydantoins, glutarimides, glutaconimides, succinimides and maleimides, of which the following are examples:
wherein Z represents Barbituric acid fi me'thyl uracil -caxboxi uracil H I c l-ethyl-G-methyl uracil 5-carboxymethyl--. amino uracil 4,5 dimethyl uracil Glutarimide 'H 'Glqtaconimida L'Cltrazinic. acid HN HI l Hydroxylamine (2) N-methylhydroxylamine (3) N-ethyl hydroxylamine (4) N-propyl hydroxylamine 5 N-isopropyl hydroxylamine (6) N,N-diethyl hydroxylamine (7) N,N-dimethylhydroxylamine 8) N-methyl-N-propyl hydroxylamine 9) N-methyl-N-isopropyl hydroxylamine l 0) N-ethyl-N-propyl hydroxylamine (1 1) N,N-diisopropyl hydroxylamine l2) N,N-di-n-propyl hydroxylamine 13) N-ethyl-N-methylbutyl hydroxylamine (l4) N-methyl-N-isobutyl hydroxylamine 15 N-n-propyl-N-n-butyl hydroxylamine 16) N-hydroxy-pyrrolidine (17) N-hydroxy-piperidine l 8) N-hydroxymorpholine (19) N-benzyl hydroxylamine H0 CHzCfi: N-ethyl-N-hydroxyethy1 hydroxylamlne N OH O IHB 0 2 N-benzyl-N-methyl hydroxylamlno H 0 C H: C1\I:
NOH HO O C CH:C H: N-hydroxyethyl-N-carboxyethyl hydroxylamlne NHOH a-Hydroxylamine-fi-phenyl propionic acid N-phenyl hydroxylamlne HOOCQNHOH N-p-carboxy phenyl hydroxylamine CHzOQ-NHOH N p-methoxy phenyl hydroxylamiue $11 (in N.Nmethy1ene bis (N-phenyl hydroxylamine) (28) 50:11
m-Hydroxylamino-benzene sultonic acid As indicated above, the most effective solutions of the herein contemplated type comprise, in addition to a cyclic imide and a hydroxyl amine, a nitrogenous base other than a hydroxylamine. Where the hydroxylamine is aliphatic, it may perform a developing function as well as a complexing function in cooperation with the cyclic imide. In any case, the addition of a nitrogenous base, which performs a complexing function exclusively, here has been found desirable. Where the hydroxylamine is aromatic, it is a relatively strong developing agent and does not cooperate effectively with the cyclic imide to form a stable silver complex. In this case, the addition of a nitrogenous base which cooperates with the cyclic imide in the performance of a complexiug function ordinarily is required. Such an additional nitrogenous base preferably is selected from the class consisting of ammonia, amines, hydrazine and aliphatic hydrazines which are soluble in aqueous alkali. As examples of nitrogenous bases selected from this class, mention may be made of:
(1) Ammonia (2) Sec. amylarnine (3) Ethylamine (4) n-Butylamine (5) Allylamine (6) Diethylamine (7) Dipropylamine (8) Trimethylamine (9) Triethanol amine 10) NH CH CH NHCH CH NH Dlethylene triamlne NH (CH CH NH) CH CH NH Tricthylene tetramlne CHzCHCHzNH:
NHCHaCHrOH N-hydroxyethyl propylene diamine NH CH CH CH NH Trimethylene diamine (14) NH CH CH NH Ethylene diamlne NHs-CHsCIi:
NH H0 CHrC: Amlnoethyl ethanol amine HOCH2CHzNHCHzCHgNHCHgCHgNHz Hydroxyethyl diethylene trlamlne NH CH CH NH) gcHgcHgNHg Tetraethylene pentamine l 8) Guanidine hydrochloride (l9) Piperidine (20) Pyrrolidine CHI e-H 7 [-C H NH1 Polyethylene imine p-Aminophenol NH on-21101 2,4-diaminophenol dihydrochlorlde Meta-amino-benzoie acid (26) Hydrazine (27) Methyl hydrazine Unsymmetrical dimethyl hydrazine The alkalinity of the solution for good results must be high, ranging from a pH of 11 to a hydroxyl ion concentration of N. As examples of bases which are capable of imparting such an alkalinity to the composition, mention may be made of alkali-metal hydroxides such as sodium and potassium hydroxide and amines such as diethylamine and allylamine. Such a nitrogenous base as diethylamine can perform, at once, both this function and a complexing function.
In one transfer process of the contemplated type, the solution is spread in a uniformly thin layer between the superposed surfaces of a photoexposed gelatino silver halide stratum and a silver-receptive stratum, for example by advancing the strata between a pair of pressureapplying rollers. The strata are maintained in superposed relation for a predetermined period, preferably of the order of 40 to 120 seconds in duration, during which exposed silver halide is reduced to silver and unreduced silver halide forms a water-soluble, complex salt which diffuses through the layer of solution to the image-receptive stratum, there to be reduced to silver and to form a visible print. At the end of this period, the silver halide stratum is stripped from the image-receptive stratum. Materials useful in such a transfer process are described in U. S. Patent No. 2,543,181, issued in the name of Edwin H. Land on February 27, 1951.
The silver-receptive stratum, preferably,- includes certain materials the presence of which, during the transfer process, has a desirable effect on the amount and character of silver precipitated on the silver-receptive stratum. Materials of this type are specifically described in copending U. S. patent applications Serial No. 727,385, filed by Edwin H. Land on February 8, 1947 (now Patent No. 2,698,245) and Serial No. 449,995, filed by Edwin H. Land on August 16, 1954 (now Patent No. 2,698,237).
A composition employed in the foregoing manner preferably is relatively viscous, of the order of 100 to 200,000 centipoises at a temperature of 20 C., so as to be easily controlled when spread. If desired, the viscosity of the composition can be increased byincluding within it a suitable thickening agent, such, for example, as a watersoluble, synthetic polymer, an insoluble, emulsifiable oil, a starch, or a gum. It is possible for such a nitrogenous base as polyethylene imine to perform, at once, both a thickening function and acomplexing function.
Stripping of the silver halide stratum from the silverreceptive stratum separates the layer of processing solution from the silver-receptive stratum or permits the layer of processing solution to remain in contact with the silverreceptive stratum in order to provide it with a protective coating. Techniques which enable such stripping to be accomplished as desired are taught in U. S. Patent No. 2,647,056, issued to Edwin H. Land on July 28, 1953. In general, the reaction product residue of the solution and silver halide, which is present on the silver image either as a trace remaining after the processing solution layer has been separated from the silver or which remains as a protective coating on the silver image, as indicated above, is colorless or pale, so as not to appreciably affect the appearance of the image and has little tendency to react with reduced silver to deteriorate the image. However, any existing tendency of this residue to harm the image may be minimized by so formulating the solution that as many of its components as possible are volatile. Thus, in a preferred form, the processing solution comprises, in addition to a cyclic imide which is not volatile, a volatile nitrogenous base, e. g., ammonia or a low molecular weight amine, as a complexing agent, and a volatile hydroxylamine, e. g., hydroxylamine or a low molecular weight hydroxylamine, as a developing agent. Here, the tendency of the processing solution residue to continue to form silver complexes is minimized by volatilization of the nitrogenous base and the tendency of the processing solution residue to harm the image and to form a colored product is minimized by volatilization of the hydroxylamine.
The following nonlimiting examples further illustrate the present invention:
EXAMPLE I Barbituric acid 9:2 Diethyl hydroxylamine 3.7 Aminoethyl ethanol amine 1.7
The excellent image which was formed in the silverreceptive stratum was of blue-black tone and moderate contrast and had a maximum density of 1.7 and a minimum density of 0.02.
Excellent results also were obtained with formulations similar to the foregoing except that: the barbituric acid was replaced by an equal quantity of sodium barbital, cyanuric acid, urazole, uracil, hydantoin, carboxymethyl barbituric acid, or 4-carboxy-uracil; the diethyl hydroxylamine was replaced by an equal quantity of dimethyl hydroxylamine or propyl hydroxylamine; the aminoethyl ethanol amine was replaced by an equal quantity of triethylene tetramine, guanidine hydrochloride or allylamine, or 3.4 parts of piperidine, pyrrolidine or hydroxyethyl propylene diamine. The characteristics of an image formed in the fore going way may be varied as desired by varying the relative proportions of the components, of a formulation of the foregoing type. Thus:
EXAMPLE II Parts by weight Water 73.6
Sodium carboxymethyl cellulose (high viscosity) 2.6
Sodium hydroxide 9.2 Urazole 10.0 Diethyl hydroxylamine 6.0
Aminoethyl ethanol amine 2.0
The resulting image was of blue-black tone and moderate contrast and had a maximum density of .98 and a minimum density of .09.
7 EXAMPLE III The following formulation produced a less contrasty EXAMPLE IV The following formulation produced a light image of low contrast having a maximum density of .86 and a minimum density of .14:
Parts by weight Water D 73.6 Sodium carboxymethyl cellulose (high viscosity) 2.6 Sodium hydroxide 9.2 Urazole 3.0 Diethyl hydroxylamine 6.0 Aminoethyl ethanol amine 2.0
EXAMPLE V The following formulation produced a contrasty image having a maximum density of 1.86 and a minimum density of .82:
Parts by weight Water 73.6 Sodium carboxymethyl cellulose (high viscosity) 2.6 Sodium hydroxide 9.2 Urazole 1.0 Diethyl hydroxylamine 6.0
As indicated above, the proportions of the various compouents may be varied within wide limits. However, where the processing period is short, for example, ranging from 40 to 120 seconds (in accordance with the now conventional duration of diffusion transfer-reversal processing periods), practical results are achieved where, in concentrations by total weight of the solution, the cyclic imide ranges from 1 to 15%, the hydroxylamine ranges from 1 to 15% and the additional nitrogenous base ranges from to 15%. In one minute, the following formulations produced images which, though distinct, were pale, indicating that ingredients in proportions outside these ranges would produce images of generally decreasing worth.
Table I Components of the solution Percentage ot'Total Weight proportions of which are varied in formulations A B,C,D,E,F,G,Handi A B 0 D E F o H r Barblturlc acid 1 15 1 15 1 15 1 15 Dlethylhydroxylamine. 1 1 15 1 15 1 15 6 vminoethyl ethanolamin 1 1 1 0 15 1 15 15 0 ater Sodium carboxymethyl cel- To make solution having pH of 12 and lulose. viscosity of 100,000 centipolses Sodium hydroxide In preparing the foregoing compositions, the sodium carboxymethyl cellulose and the sodium hydroxide first were dissolved in water at room temperature. Next, the cyclic imide was added to the solution and the two phases were mixed until the cyclic imide was completely dissolved. Simultaneously, the nitrogenous base or bases were added to the solution with suflicient mixing only to insure their dissolution, care being taken to prevent oxidation and/or volatilization of the nitrogenous base or bases.
The present invention thus provides novel difiusion transfer-reversal techniques employing silver halide developing and dissolving components which are as efiicient as corresponding conventional components and yet which leave on the image which they form a harmless residue.
Since certain changes may be made in the above composition and process without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.
What is claimed is:
1. A photographic processing composition comprising, in alkaline aqueous solution, a plurality of agents including a first complexing agent composed of a cyclic imide selected from the class consisting of compounds within the general formula:
wherein Z represents (1) atoms of a series completing a cyclic imide nucleus, said nucleus consisting of from 5 to 6 atoms of which from 1 to 3 are nitrogen and the remainder are carbon and (2) members branching from said atoms of said series, said members being selected from the class consisting of hydrogen atoms, amino radicals, aliphatic radicals containing from 1 to 4 carbon atoms, halogen atoms, keto oxygen atoms' and aromatic radicals, at most one of said members being one of said halogen atoms, keto oxygen atoms and aromatic radicals, a second complexing agent other than a cyclic imide and composed of at least one nitrogenous base other than a hydroxylamine, said nitrogenous base being selected from the class consisting of ammonia, organic amines, hydrazine and aliphatic hydrazines, and a developing agent composed of a hydroxylamine, said first complexing agent and said second complexing agent together being capable of reacting with silver halide to form a water-soluble complexing silver salt, said developing agent being capable of reducing silver halide to silver, and said second complexing agent performing a complexing function exclusively.
2. The photographic processing composition of claim 1 wherein the alkalinity of said solution ranges from a pH of 11 to a hydroxyl ion concentration of 5 N.
3. A process of forming a photographic print, said process comprising the steps of reacting substantially exposed silver halide of a photosensitive silver halide element with a silver halide developer composed of a hydroxylamine, reacting substantially unreduced silver halide of said photosensitive silver halide element, in alkaline aqueous solution, with a first complexing agent and a second complexing agent, said first complexing agent being a cyclic imide selected from the class consisting of compounds represented by the general formula:
wherein Z represents 1) atoms of a series completing a cyclic imide nucleus, said nucleus consisting of from 5 of which from 1 to 3 are nitrogen and the remainder are carbon and (2) members branching from of said series, said members being selected from the class consisting of hydrogen atoms, amino radicals, aliphatic radicals containing from 1 to 4 carbon atoms, halogen atoms, keto oxygen atoms and aromatic radicals, at most one of said members being one of said halogen atoms, keto oxygen atoms and aromatic radicals, Said second complexing agent being composed of a nitrogenous base other than a hydroxylamine and other than a cyclic imide, and being selected from the class consisting of ammonia, organic amines, hydrazine and aliphatic hydrazines, said second complexing agent performing a complexing function exclusively, transferring said complex by diffusion to an image-receptive material, and forming, at said image-receptive material, an image incorporating silver from said silver complex.
4. The photographic process of claim 3 wherein the alkalinity of said solution ranges from a pH of 11 to a hydroxyl ion concentration of 5 N.
References Cited in the file of this patent UNITED STATES PATENTS 12 2,543,181 Land Feb. 27, 1951 2,551,134 Jennings May 1, 1951 2,567,109 Howard Sept. 4, 1951 2,590,775 Kendall et al Mar. 25, 1952 2,635,048 Land Apr. 14, 1953 OTHER REFERENCES Kraft: Zeitschrift fiir Wissenschaftliche Photographic, Photophysik und Photochemie, vol. 31, No. 12, May
10 1933, pages 329-364.
Mannessier-Mameli: Chemical Abstracts, 1936, vol. 30, page 2949.
Merck Index, published by Merck and Co., Inc., Rahway, N. J., 1952, 6th edition, pages 297 and 986.
Howe Dec. 19, 1950 15 Brune: Chemical Abstracts, 1952, vol. 46, page 7448.