EP0568850A1

EP0568850A1 - Photographic silver halide systems containing water soluble cyclodextrin-adjuvant adducts

Info

Publication number: EP0568850A1
Application number: EP93106263A
Authority: EP
Inventors: Ludovic Fodor; William Robert Pangratz
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 1992-05-06
Filing date: 1993-04-16
Publication date: 1993-11-10
Also published as: JPH0627565A

Abstract

Photographic aqueous silver halide systems comprising a silver halide emulsion and a developer, wherein at least one of the emulsion or developer contain at least one non-water soluble adjuvant in the form of a water soluble adduct with cyclodextrin are advantageous in that the adjuvants can be readily incorporated into the emulsion or developer with water and without the need for organic solvents that would otherwise be required to incorporate the adjuvant, thus making for a cleaner, safer and less toxic system.

Description

BACKGROUND OF THE INVENTION

This invention relates to photographic silver halide systems generally and more particularly relates to photographic silver halide systems containing water soluble adducts of cyclodextrin and at least one adjuvant.
Photographic silver halide systems are well known in the art. Such systems comprise photographic silver halide elements, comprising a silver halide emulsion coated on a support, and the fluids used to process exposed silver halide elements, i.e., developer and fixer. These silver halide systems are widely recognized as the standard for photographic imaging used in the printing and publishing industries in particular, not to mention photography and medical or industrial radiography. Because of the unique circumstances and considerations in each of these industries, silver halide systems suitable for one industry are often not suitable for the others. Accordingly, a plethora of silver halide emulsion and developer formulations have been developed and perfected in an undying effort to provide the end user with the best system for the particular application at hand.
Despite the tremendous diversity of composition of the prior art silver halide emulsions, all such emulsions can generally be described as comprising silver halide grains dispersed in a suitable binder. The silver halide grains may be one or more of silver chloride, silver iodide and silver bromide, and may be of tabular or polyhedral morphology. The most typically used binder is gelatin, alone or in combination with other polymeric or proteinaceous binders. In some applications, the emulsion will also contain latex. In any case, the binder is almost always water soluble and the emulsions are generally termed aqueous emulsions.
Developers are typically aqueous solutions of high pH (i.e., >10) which contain at least one compound which is capable of reducing the exposed silver halide grains. The most common reducing compound (known in the art as "developing agents") is hydroquinone, although ascorbic acid is gaining popularity as a less toxic and less expensive alternative.
It is also conventional for the emulsion and/or the developer to contain at least one adjuvant. An "adjuvant," as the term is commonly understood in the art, is any compound, other than the silver halide and the binder for emulsions or the developing agent for the developers, which is present to improve or enhance some quality of the system, such as viscosity, pH, processing speed, image density, fog, etc. Although adjuvants are not necessary for the essential photographic function of the emulsion or the development of the image, the term includes compounds which improve or enhance that function, such as sensitizing dyes. Examples of other common adjuvants would include so-called high contrast agents (e.g. hydrazine compounds); antifoggants (e.g. 1-phenyl-5-mercapto tetrazole); coating aids; stabilizing agents (e.g. 2-mercapto benzothiazole); hardeners (e.g. formaldehyde), development accelerators (e.g. phenethyl quinolinium bromide) and a number of others which are well known to one of ordinary skill in the art.
Adding adjuvants to emulsions presents a particular problem in that, in most cases, proper functioning of the adjuvant requires that it be uniformly distributed throughout the emulsion. To insure a uniform distribution, it is common to add the adjuvant to the emulsion as a solution. A common problem, however, is that many, if not most, of the frequently used adjuvants are water insoluble, or at least not sufficiently soluble, and thus are incompatible with the aqueous emulsion. Therefore, in order to add such adjuvants to an aqueous silver halide emulsion in the required concentrations, it is necessary to dissolve the adjuvant in an organic solvent, such as the lower alcohols, which solvent is itself miscible with the aqueous emulsion. The same holds true for adjuvants added to developers which are not themselves soluble in the aqueous developer solutions.
The use of organic solvents in manufacturing processes in general is disadvantageous for several reasons. Organic solvents are, as a general rule, more toxic than water and thus require specialized handling and care. Organic solvents are also more expensive than water. Additionally, water is a much more environmentally suitable vehicle for waste solutions at the time of disposal. Organic solvents also tend to be flammable or explosive, especially in vapor form, and thus pose an additional safety factor to employees, particularly during the drying of photographic coatings when the organic solvents are outgassed. Finally, the increasing efforts by various environmental regulatory agencies, particularly in recent years, has increased the cost and administrative burdens of manufacturing processes when hazardous or potentially hazardous organic solvents are employed in the process.
There is thus a need in the art for a method of manufacturing silver halide emulsions and developers which reduces or eliminates the need for organic solvents.

SUMMARY OF THE INVENTION

The present invention avoids a number of the above-mentioned disadvantages and virtually eliminates the need to use organic solvents to add adjuvants to a silver halide emulsion or a developer composition. According to one aspect of the invention, there is provided a photographic silver halide system comprising an aqueous silver halide emulsion and an aqueous developer, wherein at least one of the emulsion or developer contains at least one non-aqueous soluble adjuvant as a water soluble adduct with cyclodextrin.
The terms "non-aqueous soluble" or "water insoluble" as they are used herein with respect to adjuvants is not intended to mean that the adjuvant is completely insoluble in water. To the contrary, many compounds, including the commonly used photographic adjuvants, will have some solubility in water. These terms, and those of similar meaning as used herein, should be construed as indicating a compound whose solubility in water is insufficient to obtain the desired concentration in the silver halide emulsion or developer. Such compounds are well known to those of ordinary skill in the art.

DETAILED DESCRIPTION OF THE INVENTION

Cyclodextrins are naturally occurring, non-toxic compounds commonly used in the pharmaceutical industry, having a cyclic structure comprised of alpha-(1-4) linked D-glucopyranose units. Three types of cyclodextrins are known, designated alpha, beta and gamma which differ in structure only by the number of sugar units; the alpha cyclodextrins having six units, the beta having seven units and the gamma having eight units. All three types of cyclodextrins are usable in the present invention.
Cyclodextrins are substantially water soluble compounds. The interior or cavity of the cyclodextrins, however, is hydrophobic. Thus, these compounds are capable of forming inclusion complexes or adducts (so-called "host-guest" type compounds) with non-water soluble substances. Of course, not all water insoluble compounds can complex with cyclodextrins. Rather, the ability to form an adduct depends upon the molecular dimensions of the water insoluble compound and the particular cyclodextrin being used. Most of the commonly used photographic adjuvants will form adducts with cyclodextrins.
The silver halide emulsions suitable for use in the present invention comprise a dispersion of one or more of silver chloride, bromide or iodide grains, either tabular or polymorphic, in an aqueous binder. The emulsions can be produced by any of the conventional methods such as splash or double-jet precipitation as well-known to those skilled in the art, and then dispersed in a bulking amount of gelatin or other conventional aqueous silver halide binder. The silver halide grains may also be further sensitized by digestion with chemical salts as is well known.
Developer compositions suitable for use in the present invention comprise aqueous solutions of a developing agent (e.g. hydroquinone or ascorbic acid) at relatively high pH. Typically, an alkali metal hydroxide, carbonate, phosphate , etc. is present as a pH buffer.
After the emulsion is prepared, it may be coated in one or more layers on any of the conventional supports for silver halide emulsions. The type of support will vary depending upon the desired end use of the element. For photographic elements used in the graphic arts industry, for example, it is conventional to use dimensionally stable polyethylene terephthalate which may be suitably subbed with conventional resin and/or gelatin subbing layers, for example, in order to be receptive to the aqueous emulsion. Additional layers may also be coated on the support, such as antistatic layers, backing layers, anticurl layers, antihalation layers, etc. as is well known to those skilled in the art. A thin gelatin layer may be coated over the emulsion to serve as a protective layer. The elements of this invention may be exposed and/or developed in any conventional manner suitable for the particular application.
The adjuvants adducts of this invention are prepared by mixing the desired adjuvant with an aqueous solution of cyclodextrin, which mixture is then added to the emulsion or the developer. The amount of cyclodextrin present will, of course, depend upon the amount of adjuvant that is necessary or desired in the particular emulsion or developer being prepared. Obviously, sufficient cyclodextrin should be present to form adducts with each molecule of adjuvant that is present.
With the exception of sensitizing dyes, the presence of the cyclodextrin adducts in the emulsion or the developer has not shown any undesirable effects on the physical or sensitometric characteristics of the emulsion or the developer. As indicated in the following examples, however, forming cyclodextrin-dye adducts produces a decrease in sensitometric response of the system. This decrease in sensitometry is believed to be due to a higher affinity of the dye to the cyclodextrin compounds, which reduces the amount of dye avaliable to sensitize the silver halide grains. The use of cyclodextrin-dye adducts, however, has been shown to significantly increase the water solubility of the same sensitizing dyes. Despite the disappointing results with the dyes used in the examples herein, it is anticipated that other sensitizing dyes can be used in the present invention without loss of sensitometric response.

EXAMPLES

The present invention will now be illustrated by the following examples.

EXAMPLE 1

4.4 gm of 2-(4-benzyloxyphenyl)-1-(pyridiniumacetyl)-hydrazine bromide ("BOP-HMP") was added to a solution comprising 11.35 gm of beta-cyclodextrin in 15 ml of water at 80°C. The BOP-HMP dissolved instantly, resulting in a yellow solution. The solution was hot filtered and then cooled to room temperature. 10 ml of acetone was then added, whereupon a white precipitate formed and the solution was filtered. The precipitate was then washed three times with acetone and dried at 50°C.
The precipitate was then redissolved in water and treated with NaOH. A slight color change was noticed, indicating that only a slight oxidation of BOP-HMP had occurred.
For comparison purposes, 4.4 gm of BOP-HMP was added to 15 ml of water with stirring. The BOP-HMP did not dissolve. When NaOH was added, a very rapid and pronounced oxidation occurred.

EXAMPLE 2

11.35 gm of beta-cyclodextrin was added to 15 ml of water and heated to 85°C with stirring. 1.75 gm of 1-phenyl-5-mercapto tetrazole ("PMT") was added and the temperature maintained for approximately 10 minutes at 80-85°C. The solution was then cooled to room temperature and filtered to remove the precipitate. The precipitate was rinsed with acetone and dried at 50°C. Yield was 9 gm. The presence of an FMT-cyclodextrin adduct was confirmed by Thin Layer Chromatography ("TLC"). The FMT in water without the cyclodextrin did not dissolve.

EXAMPLE 3

11.35 gm of beta-cyclodextrin was added to 30 ml of water and heated to 65°C. The cyclodextrin did not dissolve. 1.1 gm of solid Hydroquinone ("HQ") was added and a clear, transparent solution immediately resulted. The solution was cooled to room temperature, the precipitate removed by filtration, washed with acetone and dried at 50°C. Yield was 5 gm of an HQ-cyclodextrin adduct which was confirmed by TLC.

EXAMPLE 4

11.35 gm of beta-cyclodextrin was added to 30 ml of water and heated to 75°C with stirring to form a solution. 1.25 gm of solid 2-mercapto benzothiazole ("MBT") was added. Initially, the MBT was not even wetted by the solution, but after a few minutes, it dissolved and a light yellow precipitate was formed. The temperature was maintained at 75°C for 10-15 minutes before the mixture was allowed to cool to room temperature. The mixture was then filtered and the precipitate was slurried with approximately 20 ml of acetone. The slurry was filtered, rinsed with acetone and then dried at 55°C to yield 7 gm of a MBT-cyclodextrin adduct, the presence of which was confirmed by TLC.

EXAMPLES 5-13

To illustrate the effect of increasing amounts of cyclodextrin on solubility, several dispersions of 0.15 gm of sensitizing dye KF563 (a proprietary dye manufactured by Riedel de Haen, Seelze, Germany) in 100 ml of water were prepared. To these dispersions, increasing amounts of beta-cyclodextrin was added as indicated in Table 1. A 2 ml aliquot of each solution was diluted to 100 ml with water and the absorption was recorded. Because cyclodextrin does not absorb in the visible region of the spectrum, the absorption was directly related to the concentration of the KF563 dye. The results are indicated in Table 1. In each case, the pH of the solution was 5.5 (without adjustment) and the temperature was 20°C.

TABLE 1

Example No.	Cyclodextrin (gm/100 ml)	KF563 (gm/100 ml)	Absorption at 436 nm
5	0.0	0.15	0.322
6	0.2	0.15	0.433
7	0.4	0.15	0.516
8	0.6	0.15	0.593
9	0.8	0.15	0.701
10	1.0	0.15	0.799
11	1.5	0.15	0.961
12	2.0	0.15	1.185
13	2.5	0.15	1.189

These data show that the solubility of KF563 in water can be increased by adding increasing amounts of cyclodextrin, until a saturation point is reached at approximately 2 gm cyclodextrin/100 ml of water. Using these data and a calibration curve prepared by measuring the absorption of stock solutions in the usual manner, it was determined that the solubility of KF563 can be increased 300% with the addition of cyclodextrin.

EXAMPLE 14

The following mixtures were prepared:

Preparation A: 0.42 gm of 2-(p-carboxyphenyloxy)-2-pivaloyl-2',4'-dichloroacetanilide (a color coupler sold by Eastman Kodak Co., Rochester, NY) was added to 15 ml of water. The compound did not dissolve, even when heated to 85°C for 15 minutes with stirring. 1.135 gm of beta-cyclodextrin was added and the temperature maintained at 85°C for 10 minutes. The mixture was then hot filtered to obtain a clear, colorless solution.
Preparation B: 0.42 gm of the color coupler was dissolved in 15 ml of acetone. This served as a comparison control.
Preparation C: 0.42 gm of the color coupler and 1.135 gm of beta-cyclodextrin were added to 15 ml of water and heated to 85°C for 15 minutes. The mixture was allowed to cool to room temperature and then filtered.
Preparation D: 0.42 gm of color coupler was added to 15 ml of water with stirring and the mixture heated to 85°C for 15 minutes. The mixture was then cooled to room temperature and filtered.

A TLC was performed on Preparation A and B, which confirmed the presence of a color coupler-cyclodextrin adduct in Preparation A. Ultraviolet spectra were made from Preparation C and D. Preparation D gave an absorbance value of 1.4378 at 248 nm without any dilution. Preparation C had to be diluted (1 part Preparation C + 4 parts water) in order to record the spectra. An absorbance value of 1.5177 was obtained at 246 nm. These data indicate that by adding equimolar amounts of cyclodextrin to the mixture of color coupler in water, a 500% increase in solubility can be achieved.

EXAMPLES 15-22

The following Examples 15-22 and Comparative Examples A-D illustrate water soluble cyclodextrin-adjuvant adducts in silver halide emulsions.
Coatings were prepared of camera negative emulsions described in detail in Ringer, U.S.Patent 4,937,160 with experimental formulation variations as described below to illustrate the comparative effect of adding key adjuvants in the form of water soluble cyclodextrin adducts versus the adjuvants normal mode of addition.
The emulsion was comprised of 98 mole % bromide and 2 mol % iodide monodispersed grains dispersed in 80 grams per unit of gelatin. This emulsion was sensitized with sulfur and gold sensitizers and digested for 75 minutes at 129° F. The Comparative emulsion contained 0.28 g/unit of green sensitizing dye KF 508 (a proprietary dye of Reidel den Haen) added as a solution in 1:1 acetone/ethanol. The Comparative emulsion also contained as antifoggants benzotriazole (0.42 g/unit) in ethanol solution and 5-nitroindazole (0.02 g/unit) in acetone/water solution. Other stabilizers, coating aids, hardeners and other adjuvants were added as well known to those skilled in the art.
Prior to coating, additional agents were added to the Comparative emulsions as follows:
BOP-HMP (0.25 g/unit) as a methanol solution; phenidone (0.25 g/unit) as a methanol solution; hydroquinone (2.0 g/unit) as a methanol solution; and phenethyl quinolinium bromide.
The thus prepared emulsions were coated on 4 mil polyethylene terephthalate Cronar® base (E.I. du Pont de Nemours and Co.) having the normal resin and gel sub-layers at a silver coating weight of 4.4 g/m². A thin layer of gelatin (10 mg/dm².) was coated over each emulsion layer as an anti-abrasion overcoat.

The coated and dried films were exposed on a D.S. America Camera, continuous and halftone (through a Beta GNE-MR screen) targets, for 20 seconds. The exposed films were tray developed in Quanta-One™ Hybrid developer (E. I. du Pont de Nemours and Co.) at 95° F for 45 seconds. A 5% acetic acid shortstop, Du Pont's DLF fixer and water wash were used in the completion of the processing steps in the normal manner of tray processing. Sensitometry was computed in the usual manner from the sensitmetric wedges and Dmin, contrast (measured between 0.4 and 1.5 densities) and relative photographic speed (measured at density 2.5) compared between coatings. The sensitometric results of the emulsion coated films are shown in Table 2.

TABLE 2

Film	Dmin	Contrast	Speed
Comp. Ex. A	0.04	15	324
Example 15	0.04	10	136
Example 16	0.04	16	325
Example 17	0.04	15	305
Example 18	0.04	14	300
Comp. Ex. B	0.04	21	288
Example 19	0.04	23	293
Comp. Ex. C	0.04	15	191
Example 20	0.04	24	253
Comp. Ex. D	0.04	17	170
Example 21	0.04	18	292
Example 22	0.04	9	149

COMPARATIVE EXAMPLE A

Comparative Example A represents the normal method of addition of BOP-HMP nucleator, benzotriazole, 5-nitroindazole, and sensitizing dye KF 508. This emulsion produced normal sensitometry for a camera film developed in Quanta-One™ Hybrid developer.

EXAMPLE 15

Example 15 was made like Comparative Example A except that cyclodextrin (0.68 g/unit) was added prior to digestion. Comparison of the sensitometry shows cyclodextrin has desensitized the film resulting in reduced contrast and speed. This sensitometric effect is believed to be due to the cyclodextrin complexing with the sensitising dye and rendering the dye incapable of effectively sensitizing the grains. (See Example 22)

EXAMPLE 16

Example 16 was made like Comparative Example A, except that an equimolar amount of BOP-HMP was added as a cyclodextrin adduct (11.39 g/unit) in water solution instead of as a methanol solution. A comparison of sensitometry shows essentially no difference between this Example and Comparative Example A made by adding the BOP-HMP as a methanol solution.

EXAMPLES 17 and 18

Example 17 and Example 18 show, respectively, emulsions made with cyclodextrin adducts of benzotriazole (4.42 g/unit) and 5-nitoindazole (0.16 g/unit) added as water solutions in equimolar amounts of adjuvant instead of the normal mode of addition as in Comparative Example A. A comparison of sensitometry of Examples 17 and 18 to Comparative Example A shows essentially no difference attibuted to the use of cyclodextrin adducts of these adjuvants.

COMPARATIVE EXAMPLE B and EXAMPLE 19

Comparative Example B was made like Comparative Example A except to it was added a methanol solution of phenethyl quinolinium bromide (0.5 g/unit). Example 19 was made with an equimolar amount of phenethyl quinolinium bromide added as a cyclodextrin adduct (2.3 g/unit) in water solution instead of as a methanol solution. Comparison of the sensitometry between Example 19 and Comparative Example B shows essentially no difference.

COMPARATIVE EXAMPLES C and D and EXAMPLES 20 and 21

Emulsions for Comparative Example C and Example 20 were made like Comparative Example A, but to each was added respectively, phenidone (0.25 g/unit in methanol solution) and phenidone-cyclodextrin adduct (2.0 g/unit in water solution).
Emulsions for Comparative Example D and Example 21 were made like Comparative Example A, but to each was added respectively, 2.0 g/unit of hydroquinone in methanol solution and 22.6 g/unit of hydroquinone-cyclodextrin adduct in water.
For both phenidone and hydroquinone developing agents, using a cyclodextrin adduct of the developing agent in place of methanol solution increased the effectiveness of the developing agent. Comparison of the sensitometry of Comparative Example C to Example 20 and Comparative Example D and Example 21 show that the cyclodextrin adduct coatings show slightly higher contrast and higher speed.

EXAMPLE 22

Example 22 was made like the Comparative Example A except that an equivalent weight (3.28 g/unit) of the green sensitizing dye KF 508 was added as a water solution of cyclodextrin-KF 508 adduct instead of as an acetone/ethanol solution of KF 508. In a comparison of the sensitometry of Comparative Example A, it is clear that the sensitometry is not the same. Adding equivalent weight of sensitizing dye as a cyclodextrin adduct results in much less contrast and speed. It is believed that this is because the cyclodextrin so effectively complexes with the dye that the effective concentration of dye available for the grain surface sensitivity process is greatly reduced. It is not effective, therefore, to add this sensitizing dye to emulsion as cyclodextrin adduct, unless there are offsetting benefits to compensate for the loss of sensitometric response. It is believed that other sensitizing dyes, which do not have as great an affinity for the cyclodextrin, could be advantageously used in the present invention.

EXAMPLES 23-26

The following Examples 23-26 and Comparative Examples E-G illustrate the comparative effect of certain developer ingredients when added to the developer as a water solution of cyclodextrin adduct versus the compound neat or as a solution in an organic solvent.

The tests were conducted in trays using standard dilution Quanta-One™ Hybrid developer (QOD/R) as the Control developer and Quanta-One™ Camera Film, (Q.O.C.; E.I. du Pont de Nemours and Co.) as the test film. The film was exposed as described in Examples 15-22. Exposed Q.O.C. film was developed at 95° F for 22, 30, 45, or 60 seconds as a Rate-of-Development series, immersed in a shortstop solution (5% acetic acid/water), fixed for 60 seconds in Dupont DLF fixer solution, washed in water and dried. Sensitometry was computed for Dmin, Contrast and Speed as described in the above examples. Dot quality and "pepper" (small black spots occuring in unexposed film areas upon development) were evaluated qualitatively by visual inspection. The sensitometric effects were compared for the Control developer and experimental developers at a representative 45 seconds development time as typical of a practical level of development. The particular adjuvants evaluated were: BOP-HMP; PMT; MBT (as an antifoggant); and MBT (as an antisludge agent). The sensitometric results are shown in Table 3.

TABLE 3

Developer Example	Dmin	Contrast	Speed
Control	0.04	15	325
Comparative Example E	0.04	17	565
Example 23	0.04	18	565
Comparative Example F	0.04	21	130
Example 24	0.04	20	125
Comparative Example G	0.03	24	80
Example 25	0.03	26	90

COMPARATIVE EXAMPLE E and EXAMPLE 23

For Comparative Example E, to 1,000 ml of standard Quanta-One™ developer, 0.1 g/unit of BOP-HMP dissolved in 10 ml of methanol was added and film was developed and sensitometry determined. Similarly, for Example 23 to 1,000 ml of Quanta-One™ developer, an equivalent amount of cyclodextrin BOP-HMP adduct (0.74 g/unit) was added and film was developed and sensitometry determined. Comparison of the sensitometry of developed films shows that there was essentially no difference in the degree of infectious development produced adding the BOP-HMP as a cyclodextrin adduct.

COMPARATIVE EXAMPLE F and EXAMPLE 24

For Comparative Example F, 0.10 g/unit of phenyl mercaptotetrazole (PMT) in 25 ml of acetone solution was added to 1,000 ml of developer. For Example 24, an equimolar amount of PMT-cyclodextrin adduct (1.0 g/unit) was added to another 1,000 ml developer sample. Films were developed and sensitometry determined. The results show that, compared to the Control, contrast was increased and speed decreased for both developers containing the PMT, and that there was no difference when the PMT was added as a cyclodextrin adduct.

COMPARATIVE EXAMPLE G and EXAMPLE 25

2-mercaptobenzothiazole (MBT) was evaluated using 0.04 g/unit of MBT dissolved in 25 ml of acetone in one sample of developer for Comparative Example G and in another 1,000 ml sample of developer, 0.40 g/unit of cyclodextrin-MBT adduct for Example 25. Comparison of the sensitometry of the Control with both forms of MBT indicated that there was increased contrast and decreased speed with addition of MBT to the developer, and there is essentially no difference produced from adding MBT a water-soluble cyclodextrin adduct.

EXAMPLE 26

In addition to acting as an antifoggant, MBT can function as an developer antisludge agent. Sludge formation in developers in this case refers to the solubilization of a small amount of silver halide (undeveloped) emulsion into the developer with subsequent slow reduction to finely divided black metallic silver metal (sludge) over a period of time, that settles out and may cause problems adhering to processed film surfaces. Antisludge agents, like MBT, complex with the soluble silver in the developer forming lightly colored insoluble precipitate that does not adhere to films.
The effectiveness of a developer antisludge agent can be judged by developing a quantity of unexposed film in the developer and visually examining the developer appearance as it is saved for a period of several days. The color of the developer and the amount and appearance of any sludge that forms can be compared to other developer compositions treated the same way.
The antisludge behavior of the cyclodextrin-MBT was compared to standard MBT in this way. To two samples of 1,000 ml of QOD/R at 95° F, 0.04 and 0.40 g/unit respectively of MBT and MBT-yclodextrin adduct were added. In each sample of developer, 10-8"x10" sheets of unexposed BLF film (a film of high silver halide solubility; E.I. du Pont de Nemours) were developed for 45 seconds. The developer samples were observed as they were kept in closed glass containers for three days. The observations showed that in both samples, a high degree of antisludge property was evident for the MBT compounds as judged from the samples colors and amount and color of the sludge produced. The color and quantity of sludge in each sample was nearly identical.

Claims

A photographic silver halide system comprising an aqueous silver halide emulsion and an aqueous developer, wherein at least one of the emulsion or developer contains at least one non-aqueous soluble adjuvant as a water soluble adduct with cyclodextrin.
The system of claim 1, wherein said at least one adjuvant is selected from the group consisting of high contrast agents, sensitizing dyes, antifoggants, developing agents, stabilizing agents, development accelerators, antisludge agents and color couplers.
The system of claim 1, wherein said at least one adjuvant is selected from the group consisting of 2-(4-benzyloxyphenyl)-1-(pyridiniumacetyl)-hydrazine bromide, 1-phenyl-5-mercaptotetrazole, hydroquinone, 2-mercaptobenzothiazole, 2-(p-carboxyphenyloxy)-2-pivaloyl-2',4'-dichloroacetanilide, phenethyl quinolinium bromide, phenidone, benzotriazole, and 5-nitroindazole .
The system of claim 1, wherein said emulsion further comprises a gelatino silver halide emulsion.
The system of claim 1 or 4, wherein said silver halide is selected from the group consisting of silver chloride, silver bromide, silver iodide, and mixtures thereof.
The system of claim 1, wherein said developer comprises an aqueous solution of at least one developing agent selected from the group consisting of:
(a) hydroquinone; and

(b) ascorbic acid, its derivatives, and salts thereof.
The system of claim 1,2 or 3, wherein said silver halide emulsion is coated on a support and wherein said water soluble adduct with cyclodextrin is present in said emulsion.
The system of claim 7, wherein said support comprises dimensionally stable polyethylene terephthalate.
The system of claim 8, wherein said support further comprises at least one subbing layer selected from the group consisting of resin subbing layers and gelatin subbing layers.
The system of claim 7, wherein said silver halide emulsion is coated on only one side of said support.
The system of claim 7, wherein said silver halide emulsion is coated on both sides of said support.
The system of claim 1, wherein said water soluble cyclodextrin adduct is present in said developer.