US3246987A - Method for elimination of reversal reexposure in processing photographic elements - Google Patents

Description

United States Patent 3 246,987 METHOD FOR ELIMINATION 0F REVERSAL RE- EXPOSURE IN PRUCESSING PHOTQGRAPHIC ELEMENTS Wesley T. Hanson, Jr., and Howard W. Vogt, Rochester,

N.Y., assignors t0 Eastman Kodak Company, Rochester, N .Y., a corporation of New Jersey No Drawing. Filed July 11, 1962, Ser. No. 209,263

9 Claims. (Cl. 96-5?) This invention relates to an improved method of photographic processing, and more particularly, to the reversal processing of photographic silver halide emulsions.

It is known that in the processing of photographic silver halide emulsions of color films, the exposed emulsions can be subjected to a first (negative) developer which is a conventional black-and-white developer, followed by reversal re-exposure and subsequent color development.

Elimination of the reversal re-exposure step in processing photographic silver halide emulsions is a desirable improvement, particularly for multilayer color elements. Certain nucleating agents that have been used in alkaline solutions after the first development and before the color development in place of the reversal re-exposure step have not been as stable as desired at the pI-Is required in the color developer for certain photographic color elements that contain incorporated color-forming couplers in the silver halide emulsion layers.

It is, therefore, an object of our invention to provide nucleating agents which have good stability in aqueous processing solutions at pI-Is from 2 to 14.

Another object is to provide an improved nucleating bath for use in place of reversal re-exposure.

Another object is to provide a stable reversal color developer solution containing our nucleating agent which nucleates unexposed silver halide and then immediately color develops the nucleated silver halide to produce the corresponding color images.

These and still other objects which will become apparent from the following specification and claims are acomplished by use of our invention.

Acording to the method of our invention, the reversal re-exposure for the reversal processing of photographic color reproductions is eliminated by treating the photographic silver halide emulsion after a first (negative) development with an aqueous solution of a boron compound which has at least one and not more than three hydrogen to boron bonds. These boron compounds include the boranes and the borazines. In one embodiment of our invention, these boron compounds are used as nucleating agents in an aqueous nucleating bath after the negative development and before the color development. In another embodiment of our invention, these boron compounds are used as nucleating agents in the color developer solution so that no separate nucleating bath is required. In the process of nucleating the negatively developed photographic element, the previously unexposed and undeveloped silver halide grains are nucleated, that is, rendered developable upon contact with a color developing agent without being exposed to light. In the process of nucleation, no appreciable silver image is produced in the silver halide emulsion layers. However, as soon as the silver halide is nucleated, it is developable upon contact with the color developer to produce a silver and a color image. Thus, when the nucleating agent is incorporated in the color developer, a silver and a color image forms rapidly upon nucleation.

Included among the boron compounds used to advantage as nucleating agents are those of the formula:

(I) ZBI-I in which Z represents ammonia, an amine, such as an alkylamine, for example, methylamine, dimethylamme,

trimethylamine, ethylamine, ethanolamine, diethylamine, triethylamine, diethanolamine, propylamine, 3-hydroxypropylamine, dipropylamine, tripropylamine, primary-butylamine, secondary-butylamine, tertiary-butylamine, primary-amylamine, secondary-amylamine, tertiary-amyL amine, etc., a polyarnine, for example, ethylenediamine, Z-aminoethylamine borane, etc., an aromatic amine, for example, aniline, etc., a cyclic amine, for example, pyridine, 2,6-lutidine, 3,4-1utidine, 2,4-lutidine, Z-ethylpyridine, 2,4-diethylpyridine, 2,6-diethylpyridine, 3,4-diethylpyridine, 2-propylpyridine, 4-propylpyridine, 3-propylpyridine, etc., a hydrazine borane, a phosphine, such as an alkylphosphine, for example, methylphosphine, dimethylphosphine, trimethylpliosphine, ethylphosphine, diethylphosphine, triethylphosphine, propylphosphine, dipropylphosphine, tripropylphosphine, primary-butylphosphine, secondary-butylphosphine, etc., an aryl phosphine, for example, phenylphosphine, etc., an arsine, such as an alkylarsine, for example, methylarsine, dimethylarsine, trimethylarsine, propylarsine, primary-butylarsine, secondary-butylarsine, amylarsine, etc.,an arylarsine, for example, phenylarsine, etc., a stibine, such as an alkylstibine, for example, methylstibine, dimethylstibine, trimethylstibene, ethylstibine, diethylstibine, triethylstibine, propylstibine, primary-butylstibine, secondary-butylstibine, tertiary-butylstibine, etc., an arylstibine, for example, phenylstibine, and nucleating agents of the formula:

wherein R, R and R" each represent a hydrogen atom, a halogen atom, such as chlorine, bromine, fluorine, iodine, an alkyl group, such as methyl, ethyl, propyl, etc., an alkoxy group, such as methoxy, ethoxy, propoxy, etc. Included among the boron compound nucleating agents of the invention are the following typical examples which are illustrative and not intended to limit the invention:

AMINE BORANES Trimethylamine borane Diethylamine borane Triethylamine borane Tert.-butylamine borane Pyridine borane 2,6-lutidine borane POLY AMINE BORANES Ethylenediamine diborane Hydrazine diborane PHOSPHINE BORANE Dimethylphosphine borane ARSINE BORANE Dimethylarsine borane STIBINE BORANE Dimethylstibine borane BORAZINES Eorazine N,N',N-trimethyl borazine N,N',N"-trimethoxy borazine These compounds and their preparations have been described in the literature. For example, the monograph, Borax to Boranes, edited by T. Wartik, and Heinrich Ntith Hassobeyer, Berichte, vol. 93, pages 928-38 and 1078-83 (1960), describe the aliphatic amine boranes.

The pyrindine and lutidine boranes are commercially available from the Callery Chemical Company, in Pittsburgh, Pennsylvania.

The phosphine boranes, the arsine boranes a-nd stibine boranes are described in Miller et al. US. Patent 2,999,- 864, issued September 12, 1961.

The borazines are synthesized by condensation of diborane with the appropriate nitrogen compound. For example, borazine is made by condensing diborane with ammonia. N,N',N"-trialkyl borazine is produced by condensing diborane with the corresponding N-alkyl amine. An N,N'-dialkyl borazine is produced by condensing diborane with a mixture of ammonia and the appropriate N-alkylamine.

In the reversal processing of multilayer, multicolor photographic elements, the first developer forms a negative black-and-white image. Photographic elements of the multilayer, multicolor type which do not contain color-forming couplers in the silver halide emulsion layers then are given a selective reveral re-exposure of one silver halide emulsion layer at a time followed by color development of the reversal exposed layer with a color developer containing a color-forming coupler which reacts with the oxidized p-phenylenediamine type developer to form the appropriate dye image corresponding to the positive silver image formed. After selective reversal re-exposure and color development of one layer, a second layer is selectively reversal re-exposed and color developed, then the third layer is selectively reversal re-exposed and color developed. The silver images and remaining silver halide are then removed by bleaching and fixing to leave the three dye images. The nucleating agents of our invention are used to advantage to eliminate the reversal re-exposure required for the last color development step. For this purpose, the nucleating agents are either used in a nucleating bath to which the film is contacted after the second layer is color developed and before the third layer is color developed or alternatively, the nucleating agent is incorporated in the color developer used to develop the third layer.

Particularly useful color films for reversal processing according to the method of our invention are films comprising a conventional support, such as cellulose esters, glass, polyester film, polyvinyl acetal film, polycarbonate film, etc., having coated thereon at least two silver halide layers which have been sensitized to particular regions of the spectrum. These emulsions have incorporated therein the color-forming components or couplers, which combine with the oxidation products of the photographic color developers, to produce the desired color images. For example, a typical color film, useful in practicing our invention comprises a support having coated thereon a red-sensitized photographic silver halide emulsion having incorporated therein a coupler for the cyan image (e.g., a phenolic coupler), a greenesensitized photographic silver halide emulsion having incorporated therein a coupler for the magenta image (e.g., pyrazolone coupler), and a bluesensitized photographic silver halide emulsion containing a coupler for the yellow image (e.g., a coupler containing an open-chain ketomethylene group). The photographic element can also contain conventional interlayers and filter layers, such as a yellow filter layer beneath the blue-sensitized emulsion to prevent exposure by blue light to either the redor green-sensitized emulsion. Photographic color films of the above-described type can be processed by a technique requiring fewer steps than the processing of color films of the multilayer, multicolor type mentioned above. For the processing of the emulsions having coupler compounds incorporated therein, it is only necessary to treat the exposed color film with the usual type of black-and-white developer for producing a negative silver image, followed by treatment with the aqueous nucleating solution and followed by conventional color developer or alternatively, followed by treatment with the color developer to which has been added one of" our nucleating agents.

Our nucleating baths in their simplest form comprise an aqueous solution of the boron compound nucleating agent. The pH of the solution is conveniently adjusted by adding a suitable alkaline material, such as sodium hydroxide, sodium carbonate, etc., or a suitable acidic material, such as acetic acid. Our nucleating agents are stable in aqueous solution at pHs as low as 3 and are thus useful in the range from 3 to 13, the particular level chosen depending upon the sensitometric results desired.- The nucleating agents can be used to advantage at con-- centrations above 1 mg. per liter. Usually they are used in the range from 1 to 1,000 mg. per liter. The preferred. concentration is from about to 400 mg. per liter.

Similarly, color developers containing at least 1 mg.- per liter of one of our boron compound nucleating agents-'- are used to advantage. Usually, they are used in the range from 1 to 100 mg. per liter, with the preferred concentration from about 10 to 100 mg. per liter. Such color developers may be of the type used to develop Kodachrome film (that is, the developer contains the color-forming coupler) or of the type color developer used to process coupler incorporated silver halide emulsion layers.

The following typical examples will further illustrate the nucleating step or combined nucleating and color development step of our invention. 1

Example 1 A photographic multilayer color element containing three differentially sensitized photographic silver halide emulsion layers, having color-forming couplers incorporated therein, was exposed to a step wedge in a sensitometer. The exposed color film Was then developed in a developer having the following composition:

Water to make 1.0 liter.

The element was then washed with water and treated in a hardening bath having the composition:

G. Potassium chrome alum crystals 30.0 Water to make 1.0 liter. The element was then treated for 1 minute in a nucleating bath having the composition:

G. Sodium hexametaphosphate 1.0 Sodium hydroxide 1.5 Tert.-butylamine borane 0.4

Water to make 1.0 liter.

The element was then treated in a color developer having the following composition:

Benzyl alcohol, cc. 6.0 Sodium hexametaphosphate, g. 2.0 Sodium sulfite, anhydrous, g. 5.0 Trisodium phosphate, g. 40.0 Potassium bromide, g. 0.25 0.1% solution of potassium iodide, cc. 10.0 Sodium hydroxide, g. 6.5

Color developer, g. 11.33 Ethylenediamine sulfate, g. 7.8 Citrazinic acid, g. 1.5 Water to make 1.0 liter.

N ethyl N (fi-methanesulton mld h 1 toluidlne sesqulsulfate monohydmte, ct y m The element was then washed thoroughly with water and treated in a clearing and fixing bath having the following composition:

G. Sodium thiosulfate 150.0 Sodium bisulfite 20.0

Water to make 1.0 liter.

The element was then treated in a bleach bath having the following composition:

G. Potassium dichromate 5.0 Potassium ferricyanide 70.0 Potassium bromide 20.0

Water to make 1.0 liter.

The element was again washed and treated once again with the clearing and fixing bath identified above. The element was again washed and treated in a stabilizing bath having the following composition:

Formaldehyde (37% by weight), cc. 7.0 Dispersing agent,** g. 0.5 Water to make 1.0 liter.

Such as Triton-X 100, Le, an alkylaryl polyether alcohol (octylphenoxy polyethoxy ethanol).

Another piece of the same multilayer color element was given the same exposure and process as described above except that the usual white light reversal re-exposure was used in place of the nucleating bath of our invention.

Still another piece of the same multilayer color element was given the same exposure and process except that no nucleating bath or reversal re-exposure was used.

A comparison of the processed elements showed that the element given our nucleating bath treatment had sensitometric quality comparable to the element given the reversal re-exposure. The element that received neither treatment with the nucleating bath or reversal re-exposure during the processing was unsatisfactory.

Example 2 Photographic multilayer color elements such as were used in Example 1 were exposed and processed using the nucleating bath in place of reversal re-exposure but substituting for the tert.-butylamine borane, trimethylamine borane, diethylamine borane, triethylamine borane, pyridine borane, and 2,6-lu-tidine borane.

The processed elements showed that each of these nucleating baths gave good sensitometric results.

Example 3 Photographic multilayer color elements such as were described in Example 1 were exposed to a step wedge in a sensitometer in the usual Way. These were processed as described in Example 1 with the following exceptions, the boron compound nucleating agent was added to the color developer solution to give a concentration of 0.10 gram per liter, no separate nucleating bath was used (nor was reversal re-exposure used). Good sensitometric results were obtained by processing color elements through processes in which trirnethylamine borane, diethylamine borane, triethylamine borane, tert.-b-utylamine borane, pyridine borane and 2,6-lutidine borane were used as the nucleating agent in the color developer. Although the pH of these developers was at 11.60 and lower, the boron compounds showed no evidences of decomposition.

Similarly, other boranes of our invention, such as the phosphine, arsine, and stibine boranes, etc., and the borazines and substituted borazines of our invention can be used to advantage.

Color development, as described in the above examples, can be carried out using any of the Well known color-forming developers which are capable of coupling with the color-forming components or couplers. Particularly useful color-forming developers are the phenylenediamines and substituted derivatives thereof. Typical of such color-forming developers are the sulfonamidosubstituted p-phenylenediamines disclosed in Weissberger US. Patent 2,548,574, issued April 10, 1951, the substituted p-phenylenediamines disclosed in Wei-ssberger et al. US. Patents 2,552,2402, issued May 8, 1951, and the substituted p-phenylenediamines disclosed in Weissberger et al. US. Patent 2,566,271, issued August 28, 1951. Other phenylenediamine color-forming developers can be employed to like advantage in the process of our invention.

Similarly, our nucleating agents are used in processes for multilayer, multicolor type films. They are also used in black-and-white reversal processes in aqueous nucleating baths to eliminate the need for reversal reexposure. In a black-and-white process, the negative development is followed by a water wash, a bleach, clearing bath, water wash, aqueous nucleating bath and positive development.

Our nucleating agents are valuable for use in nucleating baths or directly in color developers used in processing multilayer color photographic elements, since their use eliminates the need for reversal re-exposure. Our nucleating agents are especially valuable in processing color photographic elements which contain the colorforming couplers in the emulsion layers because they are stable in aqueous solutions at much lower pHs than are some of the prior art nucleating agents. Some of the prior art nucleating agents when used at pH levels where they are stable, have a strong tendency to produce undesirable stains in the processed elements. Color photographic elements processed by our reversal process have good sensitometric characteristics.

The invention has been described in detail with particular reference to preferred embodiments thereof but it will be understood that variations and modifications can i be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

We claim:

'1. In a method of producing a photographic color reproduction comprising exposing to a colored image a photographic element containing at least two photographic silver halide emulsion layers which have been differentially sensitized to different spectral regions, developing said photographic element to a negative blackand-white image by treatment with a photographic blackand-white developer, contacting said photographic element with a nucleating agent for sufiicient time to nucleate previously unexposed silver halide and render it developable to a visible image upon contact with a second developer, and developing said photographic element in a photographic color developer solution in the presence of a color-forming compound which couples with the oxidation products of said photographic color developer to produce a colored image, the step comprising nucleating said previously unexposed silver halide by contacting said photographic element with an aqueous solution of a boron compound nucleating agent selected from those having the formula:

(I) ZBH wherein Z represents a member selected from the class consisting of ammonia, an amine, an ethylenediamine borane, a hydrazine borane, a phosphine, an arsine, and a stibine, and the formula:

wherein R, R, and R each represent a member selected from the class consisting of the hydrogen atom, a halogen atom, an alkyl group, and an alkoxy group, said aqueous solution having a pH in the range from about 2 to 14, and containing at least 1 mg. of said boron compound per liter of solution.

2. In a method of reproducing a photographic color reproduction comprising exposing to a colored image a photographic element comprising a support having coated thereon three photographic silver halide emulsion layers, one of said layers being sensitive to the red region of the spectrum and having dispersed therein a cyanimage-forrning coupler, one of said layers being sensitive to the green region of the spectrum and containing a magenta-imageforming coupler, and a third one of said layers being sensitive to the blue region of the spectrum and containing a yellow-image-forming coupler, developing said photographic element in a photographic black-and-white developer to produce a negative image, contacting said photographic element with a nucleating agent for a sufficient time to nucleate the previously unexposed silver halide and render it developable to a Visible image by developing said element in a photographic phenylenediamine color developer to produce colored images bearing a complementary relationship to the color in the original being reproduced, contacting said photographic element with a photographic clearing and fixing bath, contacting said element with an oxidizing bath to remove residual silver salts from said photographic silver halide emulsion layers, the step of nucleating said previously unexposed silver halide by contacting said photographic element with an aqueous solution of a boron compound nucleating agent selected from those having the formula:

(I) ZBH wherein Z represents a member selected from the class consisting of ammonia, an amine, an ethylenediamine borane, a hydrazine borane, a phosphine, an arsine, and.

a stibine, and the formula: (I III /N II1I3 Iii-H R-N N-R B wherein R, R, and R each represent a member selected from the class consisting of the hydrogen atom, a halogen atom, an alkyl group, and an alkoxy group, said aqueous solution having a pH in the range from about 2 to 14, and containing at least 1 mg. of said boron compound per liter of solution.

3. A photographic reversal process of claim 2 in which the step of nucleating the photographic element is accomplished by treating said element with the aqueous solution of the boron compound nucleating agent before contacting said film with the photographic color developer solution.

4. A photographic reversal process of claim 2 in which the step of nucleating and color developing the photographic element is accomplished by treating said element in the photographic color developer to which has been added at least 1 mg. of the boron compound nucleating agent per liter of said developer 5. A photographic reversal process of claim 2 in which the boron compound nucleating agent is tert-butylamine borane.

6. A photographic reversal process of claim 2 in which the boron compound nucleating agent is pyridine borane.

7. A photographic reversal process of claim 2 in which the boron compound nucleating agent is -2,6-lutidine borane.

8. A photographic reversal process of claim 2 in which the boron compound nucleating agent is dimethylamine borane.

9. A photographic reversal process of claim 2 in which the boron compound nucleating agent is trie'thylamine borane.

References Cited by the Examiner UNITED STATES PATENTS 2,150,704 3/1939 Ville 96 59 2,159,466 5/1939 Wilmanns et a1. 96 59 2,588,982 3/1952 Ives 96-94 2,984,567 5/1961 Henn et al. 96 59 2,999,864 9/1961 Miller et al. 260-240 NORMAN G. TORCHIN, Primary Examiner.

Claims (1)

1. 2. IN A METHOD OF REPRODUCING A PHOTOGRAPHIC COLOR REPRODUCTION COMPRISING EXPOSING TO A COLORED IMAGE A PHOTOGRAPHIC ELEMENT COMPRISING A SUPPORT HAVING COATED THEREON THREE PHOTOGRAPHIC SILVER HALIDE EMULSION LAYERS, ONE OF SAID LAYERS BEING SENSITIVE TO THE RED REGION OF THE SPECTRUM AND HAVING DISPERSED THEREIN A CYANIMAGE-FORMING COUPLER, ONE OF SAID LAYERS BEING SENSITIVE TO THE GREEN REGION OF THE SPECTRUM AND CONTAINING A MAGENTA-IMAGE-FORMING COUPLER, AND A THIRD ONE OF SAID LAYERS BEING SENSITIVE TO THE BLUE REGION OF THE SPECTRUM AND CONTAINING A YELLOW-IMAGE-FORMING COUPLER, DEVELOPING SAID PHOTOGRAPHIC ELEMENT IN A PHOTOGRAPHIC BLACK-AND-WHITE DEVELOPER TO PRODUCE A NEGATIVE IMAGE, CONTACTING SAID PHOTOGRAPHIC ELEMENT WITH A NUCLEATING AGENT FOR A SUFFICIENT TIME TO NUCLEATE THE PREVIOUSLY UNEXPOSED SILVER HALIDE AND RENDER IT DEVELOPABLE TO A VISIBLE IMAGE BY DEVELOPING SAID ELEMENT IN PHOTOGRAPHIC PHENYLENEDIAMINE COLOR DEVELOPER TO PRODUCE COLORED IMAGES BEARING A COMPLEMENTARY RELATIONSHIP TO THE COLOR IN THE ORIGINAL BEING REPRODUCED, CONTACTING SAID PHOTOGRAPHIC ELEMENT WITH A PHOTOGRAPHIC CLEARING AND FIXING BATH, CONTACTING SAID ELEMENT WITH AN OXIDIZING BATH TO REMOVE RESIDUAL SILVER SALTS FROM SAID PHOTOGRAPHIC SILVER HALIDE EMULSION LAYERS, THE STEP OF NUCLEATING SAID PREVIOUSLY UNEXPOSED SILVER HALIDE BY CONTACTING SAID PHOTOGRAPHIC ELEMENT WITH AN AQUEOUS SOLUTION OF A BORON COMPOUND NUCLEATING AGENT SELECTED FROM THOSE HAVING THE FORMULA: (I) ZBH3 WHEREIN Z REPRESENTS A MEMBER SELECTED FROM THE CLASS CONSISTING OF AMMONIA, AN AMINE, AN ETHYLENEDIAMINE BORANE, A HYDRAZINE BORANE, A PHOSPHINE, AN ARSINE, AND A STIBINE, AND THE FORMULA: