DE19751447A1 - Spectrally sensitized photographic silver halide emulsions - Google Patents

Abstract

Spectrally sensitized photographic silver halide emulsions containing 1-aminoimidazol-2-selenone compounds of formula (I). Spectrally sensitized photographic silver halide emulsions are ripened in the presence of 1-aminoimidazol-2-selenone compounds of the formula (I): R<1> = H, alkyl, alkoxycarbonyl, carbamoyl, carbimidoyl, sulfolanyl, sulfonyl, sulfamoyl, aryl or hetaryl; R<2>, R<3> = H, alkyl, alkoxycarbonyl, aryl or hetaryl, or R<2> and R<3> may together complete a 5-7 membered carbocyclic ring, a pyrrole ring or a thiophene ring, with the proviso that in the case of a 6-membered carbocyclic ring, a benzoid ring is excepted. Independent claims are included covering: (a) 1-aminoimidazol-2-selenone compounds of formula (I) and; (b) photographic silver halide emulsion containing a compound (I).

Description

The invention relates to a photographic silver halide emulsion with a new selenium ripening agent has matured. The invention further relates to these selenium ripening agents and a photographic recording material containing a silver halide so ripened nidemulsion contains.

The ripening of silver halide emulsions serves to increase the photosensitivity of To increase silver halide emulsions without increasing the fog (see Ullmann's Encyclopedia of Industrial Chemistry, Vol. A 20 (1992), p. 36 ff).

A variety of compounds and methods have been proposed with which the ripening is to be carried out. The best known ripening agents are gold and Sulfur compounds, e.g. B. sodium thiosulfate as a sulfur compound. For that with it achieved sensitivity has been further increased, the sulfur Replace all or part of the compound with selenium compounds (EP-A-661 589). A comprehensive description of the state of the art in the field of selenium photosensitive silver halide emulsions can be found in DE-A-43 44 164, EP-A-542 306, EP-A-567 151, EP-A-572 663, EP-A-619 515, EP- A-66 1 589, US-A-5 215 888, US-A-5 393 655, US-A-5 459 027 and US-A-5 395 745.

However, the increase in sensitivity achieved with the known ripening agents is for a number of purposes are insufficient. In particular, many of the known solve Selenium ripening agent, but also many organic sulfur ripening agents, for example the Diacetylthiourea, a veil rise that is used for a number of products which require high sensitivity, low graininess and low fog become unacceptable. This is particularly true for silver halide emulsions essentially tabular crystals.

The object of the invention was to overcome these disadvantages. It has now been found that the task is solved with new selenium ripening agents.  

The invention therefore relates to a spectrally sensitized photographic silver halide emulsion, characterized in that it is obtained by adding at least one compound of the formula I.

wherein
R _{1 is} hydrogen, alkyl, alkoxycarbonyl, carbamoyl, carbimidoyl, sulfonyl, sulfolanyl, sulfamoyl, aryl or hetaryl and
R ₂ , R _{3 are} hydrogen, alkyl, alkoxycarbonyl, aryl or hetaryl,
and wherein R ₂ and R _{3 may be the} same or different or together may form a 5- to 7-membered carbocyclic ring, a pyrrole ring or a thiophene ring, with the exception of a benzoid ring in the case of a 6-membered carbocyclic ring.

An alkyl radical represented by R ₁ to R ₃ or contained therein can be straight-chain, branched or cyclic. Particularly preferred hetaryl radicals are benzothiazol-2-yl, pyridinyl, pyrimidin-2-yl and thienyl. A 5- to 7-membered carbocyclic ring formed by R ₂ and R ₃ may also contain a fused aromatic ring.

Particularly suitable compounds of the formula I are given below:

1-Amino-3-alkylbenzimidazole-2-selenones have been developed by V.V. Kuz'menko in Chemistry of Heterocyclic Compounds, Volume 26, No. 12 (1990) 1406.

However, the 1-aminoimidazole-2-selenones of the formula I are new. Another part of the The invention therefore relates to the compounds of the formula I. They are prepared ana log of the preparation of the cyclic thioketones from J. Schantl, H. Kahlig and M. Prean, Heterocycles 37 (1994) 1873.

Preparation of Compound I-3 (Synthesis Example) 1. Compound A (preliminary stage)

65 g (0.346 mol) of freshly prepared cyclohexanone-phenylhydrazone (synthesized according to A. Baeyer, Liebig's Annalen der Chemie 278 (1894) 105) are dissolved in 290 ml of pyridine, and 89 g of iodine (0.35 mol) are added with cooling in several portions that the temperature does not rise above 60 ° C. The mixture is allowed to cool, 500 ml of water are added, the precipitated crystals are filtered off, washed with 500 ml of water, stirred with 150 ml of cold isopropanol and suctioned off again.
Yield: 89 g (75 mol%)
Melting point: 123 ° C.

2. Compound I-3

17.1 g (50 mmol) of compound A are suspended in 200 ml of dimethylformamide, 14.4 g (100 mmol) of potassium selenocyanate are added and the mixture is heated at 90 ° C. for 3 hours. Then 0.5 g of excreted selenium is suctioned off, the filtrate is stirred into 800 ml of ice water and suction filtered. The crystals are stirred with a little methanol and suction filtered again. For cleaning can be recrystallized from acetonitrile.
Yield: 9.0 g (61 mol%)
Melting point 196 to 197 ° C.

The silver halide emulsion according to the invention preferably consists of AgBrI or AgBrICl crystals with up to 15 mol% iodide and up to 20 mol% chloride or from AgClBrI, AgClI or AgClBr crystals with at least 50 mol% chloride.

The emulsion preferably consists of at least 50% of the projected area tabular crystals with an aspect ratio of at least 3. Special the aspect ratio is preferably 4 to 8.

Aspect ratio is the ratio of the average diameter of the same area circle of the projection surface of the crystal to the thickness of the crystal plate chen.

In a further preferred embodiment, the emulsion consists in part of at least 50% from hexagonal tabular crystals, with emulsions are particularly preferred, the proportion of hexagonal tabular crystals min is at least 70% and its neighboring edge ratio is between 2: 1 to 1: 1:

Emulsions whose crystals have a narrow grain size are also preferred have division.

The distribution width V of an emulsion is defined as

V ≦ 25% is particularly preferred ≦ 20%.

However, advantageous properties are also found in emulsions those that do not consist essentially of crystals with a tabular habit, in particular their emulsions of silver chloride or silver bromide chloride.  

The compounds of the formula I are preferably used in an amount of 10 ^-8 to 10 ^-3 mol / mol Ag, in particular 10 ^-6 to 10 ^-5 mol / mol Ag and in particular in the time interval from the beginning of the chemical ripening to the end of the spectral sensitization added.

The compounds of the invention are either as a solution in water or in an organic solvent or used in dispersed form. As an orga nical solvents are preferred water-miscible compounds, e.g. As methanol, ethanol, isopropanol, tetrahydrofuran, phenoxyethanol or 3-hydroxypropionitrile.

Chemical ripening can therefore also take place in the presence of the spectral sensitizers be made.

In a preferred embodiment, chemical ripening becomes the silver halo genidemulsion in the presence of the organic selenium compounds according to the invention and in the presence of sodium thiosulfate and in the presence of a silver halide Complexing agent performed.

Suitable silver halide complexing agents are:

• a) thioethers such as B.
  
• b) N-heterocycles, especially imidazoles, oxazoles, thiazoles, triazoles, thia diazoles, oxadiazoles, pyridines, tetrazoles and pyrimidines, by alkyl, alkenyl, aryl, halogen, carboxy, carbonamido, carbalkoxy, sulfo, sulfon amido, sulfoalkyl, alkylthio or amino can be substituted.
  Examples of suitable N-heterocycles are the compounds I-1 to I-36 on pages 3 to 7 of EP-A-595 031.
• c) thioureas such. B.
  
• d) compounds with an -O-CS-N or -S-CS-N group such as. B.
  
• e) sulfites such as B. K ₂ SO ₃ and
• f) thiocyanates such. B. KSCN and NH ₄ SCN.

The silver halide complexing agents are usually used in an amount of 10 ^-7 to 10 ^-1 mol / mol silver halide, preferably in an amount of 5.10 ^-5 to 5.10 ^-3 mol / mol silver halide.

The ripened emulsions according to the invention can be stabilized with heterocyclic NH or SH compounds in a known manner, in particular with those which have an acidic group, e.g. B. a -SO ₃ H or -COOH group. The stabilizers are preferably added after the spectral sensitization and selected so that they do not displace the sensitizing dye or the sensitizing dyes from the silver halide crystals of the emulsion and also do not hinder the bleaching of the image silver during processing.

Examples of particularly suitable stabilizers are listed below:

Another part of the invention relates to a photographic material which contains at least one silver halide emulsion according to the invention.

In a preferred embodiment of this part of the invention it is a color photographic recording material.

Examples of color photographic materials are color negative films, color reversal films, Color positive films, color photographic paper, color reversal photographic paper, color sensitive materials for the color diffusion transfer process or silver color bleaching process.

The photographic materials consist of a support on which at least one photosensitive silver halide emulsion layer is applied. Suitable as a carrier especially thin films and foils. An overview of substrates and Auxiliary layers applied to their front and back are in Research Discio sure 37254, part 1 (1995), p. 285 and in Research Disclosure 38957, part XV (1996), P. 627.  

The color photographic materials usually contain at least one red sensitive, green-sensitive and blue-sensitive silver halide emulsion layer and optionally intermediate layers and protective layers.

Depending on the type of photographic material, these layers can be applied differently to be in order. This is shown for the most important products:

Color photographic films such as color negative films and color reversal films show in the the following sequence on the carrier 2 or 3 red-sensitive, cyan-coupling silver halide emulsion layers, 2 or 3 green-sensitive, purple-coupling silver halide emulsion layers and 2 or 3 blue-sensitive, yellow-coupling silver halide emulsion layers. The layers of the same spectra sensitivity differ in their photographic sensitivity, whereby the less sensitive sub-layers are usually arranged closer to the carrier are than the more sensitive sub-layers.

Between the green sensitive and blue sensitive layers is common a yellow filter layer is applied, which prevents blue light from lying in the below layers.

The possibilities of the different layer arrangements and their effects photographic properties are described in J. Inf Rec. Mats., 1994, Vol. 22, Pages 183-193 and in Research Disclosure 38957 Part XI (1996), p. 624 ben.

Color photographic paper, which is usually much less sensitive to light than a color photographic film shows in the order given below the carrier usually each a blue-sensitive, yellow-coupling silver halide emulsion layer, a green-sensitive, purple-coupling silver halide emulsion layer and a red-sensitive, cyan-coupling silver halide emulsion layer on; the yellow filter layer can be omitted.  

Deviations in the number and arrangement of the light-sensitive layers can lead to Achieve certain results. For example, everyone highly sensitive layers in a layer package and all low-sensitive layers Layers combined to form another layer package in a photographic film be taken to increase the sensitivity (DE-2 530 645).

Essential components of the photographic emulsion layers are binders, Silver halide grains and color couplers.

Information on suitable binders can be found in Research Disclosure 37254, Part 2 (1995), p. 286 and in Research Disclosure 38957, Part IIA (1996), p. 598.

Information about suitable silver halide emulsions, their preparation, maturation, stabilization lization and spectral sensitization including suitable spectral sensitizers can be found in Research Disclosure 37254, Part 3 (1995), p. 286, in Research Disclosure 37038, Part XV (1995), p. 89 and in Research Disclosure 38957, Part VA (1996), p. 603.

Photographic materials with camera sensitivity usually contain silver bromide iodide emulsions, which may also contain small amounts of silver chloride can hold. Photographic copying materials contain either silver chloride bromide emulsions with up to 80 mol% AgBr or silver chloride bromide emulsions with over 95 mol% AgCl.

Information on the color couplers can be found in Research Disclosure 37254, Part 4 (1995), p. 288, in Research Disclosure 37038, Part II (1995), p. 80 and in Research Disclosure 38957, Part XB (1996), p. 616. The maximum absorption of the dyes formed from the couplers and the color developer oxidation product is preferably in the following ranges: yellow coupler 430 to 460 nm, purple couplers 540 to 560 nm, cyan couplers 630 to 700 nm.  

In color photographic films, to improve sensitivity, grainy speed, sharpness and color separation are often used in the compounds involved in the reaction release compounds with the developer oxidation product that have a photographic effect are sam, e.g. B. DIR couplers that release a development inhibitor.

Information on such compounds, in particular couplers, can be found in Research Disclosure 37254, Part 5 (1995), p. 290, in Research Disclosure 37038, Part XIV (1995), p. 86 and in Research Disdosure 38957, Part XC (1996), p. 618.

The mostly hydrophobic color coupler, but also other hydrophobic components of the Layers are usually dissolved in high-boiling organic solvents or dispersed. These solutions or dispersions are then in an aqueous Binder solution (usually gelatin solution) emulsified and lie after Drying the layers as fine droplets (0.05 to 0.8 µm diameter) in the Layers before.

Suitable high-boiling organic solvents, methods for incorporation into the Layers of photographic material and other methods, chemical compound Introducing solutions into photographic layers can be found in Research Disclosure 37254, Part 6 (1995), p. 292.

The usually indicated between layers of different spectral sensitivity ordered non-photosensitive interlayers may contain agents that have a unwanted diffusion of developer oxidation products from a photosensitive in a different light-sensitive layer with different spectral sensitivity prevent bilization.

Suitable connections (white coupler, scavenger or EOP catcher) can be found in Research Disclosure 37254, Part 7 (1995), p. 292, in Research Disclosure 37038, Part III (1995), p. 84 and in Research Disclosure 38957, Part XD (1996), p. 621.  

The photographic material can also UV-absorbing compounds, whiteners, spacers, filter dyes, formalin scavengers, light stabilizers, anti-oxidants, D _Min dyes, additives to improve the stability of dyes, couplers and whites as well as to reduce the color fog, plasticizers (latices) , Biocide and others included.

Suitable compounds can be found in Research Disclosure 37254, Part 8 (1995), p. 292, in Research Disclosure 37038, parts IV, V, VI, VII, X, XI and XIII (1995), p. 84 ff and in Research Disciosure 38957, parts VI, VIII, IX and X (1996), p. 607 and 610 ff.

The layers of color photographic materials are typically hardened, i.e. that is binder used, preferably gelatin, is by suitable chemical Ver networked.

Suitable hardener substances can be found in Research Disclosure 37254, Part 9 (1995), P. 294, in Research Disclosure 37038, Part XII (1995), p. 86 and in Research Disclosure 38957, Part IIB (1996), p. 599.

After photographic exposure, color photographic materials become their character processed according to different processes. Details on ver procedures and chemicals required for this are in Research Disclosure 37254, Part 10 (1995), p. 294, in Research Disclosure 37038, parts XVI to XXIII (1995), p. 95 ff and in Research Disclosure 38957, parts XVIII, XIX and XX (1996), p. 630 ff published together with exemplary materials.

example 1

The example describes the preparation of a silver bromide iodide according to the invention emulsion with essentially tabular crystals.

Emulsion 1/1 (comparison)

A silver bromide iodide emulsion with an average grain diameter of the same area of 1.5 µm, a distribution width V = 23%, an aspect ratio of 7.5 and an average iodide content of 9 mol% is mixed with 2 µmol tetrachloroauric acid, 250 µmol potassium thiocyanate and 10 µmol Sodium thiosulfate per mole of AgNO ₃ matured to the sensitivity optimum and then sensitized with 300 mg of a mixture of the red sensitizers RS-1, RS-2 and RS-3 in a weight ratio of 3: 6: 1.

The emulsions 1/2 and 1/3 (comparison) and 1/4 to 1/6 (invention) are corresponding produced accordingly, but the amount of sodium thiosulfate is reduced to 4 µmol and an additional 5 µmol of the ripening agents listed in Table 1 are used.

Emulsions 1/1 to 1/6 are applied after the addition of a color coupler emulsate of the following composition to a 120 μm thick, subbed carrier made of cellulose triacetate (amounts per m ² ):

0.85 g emulsion (based on AgNO ₃ ),
0.70 g gelatin,
0.30 g cyan coupler C-1,
0.45 g tricresyl phosphate (CPM).

A protective layer of the following composition was applied thereon (amounts per m ² ):

0.01 g gelatin,
0.02 g hardener H-1.

The samples were placed behind an orange filter and a graduated gray wedge exposed to daylight and then according to the "The British Journal of Photo graphy "1974, p. 597 processed. The sensitivity is each determined at a density of 0.2 over veils in relative DIN units. The  The sensitivity of the emulsion 1/1 is arbitrarily set to 100 set.

The results are shown in Table 1.

Table 1

From the examples it can be seen that a better sensitivity / fog ratio is obtained with the selenium ripening agents according to the invention.

Example 2

The example describes the production of a silver chlo ripened according to the invention ridemulsion with essentially cubic crystals.

Emulsion 2/1

The following solutions are used:

Solution 1: 7000 ml of demineralized water
600 g gelatin
1.0 g of 1- (3,6-dithiaoctyl) urea

Solution 2: 7000 ml of demineralized water
1300 g silver nitrate

Solution 3: 7000 ml of demineralized water
3000 g sodium chloride.

Solutions 2 and 3 are in the course of 120 minutes at 60 ° C and a pAg of 7.7 was simultaneously added to solution 1 with vigorous stirring. It will be cubic Silver chloride emulsion obtained with an average particle diameter of 0.90 microns. The distribution width V is 17%. The gelatin to silver ratio is 0.18. The emulsion is flocked with polystyrene sulfonic acid in a known manner and washed and redispersed with so much gelatin that the gelatin / silver ratio is 0.56. The emulsion contains 1 mol of silver chloride per kg.

The mixture is then optimally ripened at pH 4.5 with 3.5 μmol KAuCl ₄ and 1.5 μmol Na ₂ S ₂ O ₃ per mol Ag at 60 ° C. After chemical ripening, the emulsion is spectrally sensitized with 300 μmol of the blue sensitizer BS-1 and stabilized with 280 μmol of 1- (3-acetaminophenyl) -5-mercaptotetrazole.

The emulsions 2/2 to 2/5 differ in that only 1.5 µmol KAuCl ₄ and 0.5 µmol Na ₂ S ₂ O ₃ and an additional 2.0 µmol of the ripening agents listed in Table 2 are used.

A yellow coupler emulsifier is added to the emulsions and poured onto a paper coated on both sides with polyethylene (quantities per m ² ):

0.63 g emulsion (based on AgNO ₃ ),
1.38 g gelatin,
0.95 g yellow coupler Y-1,
0.29 g CPM.

The material is hardened by applying a protective layer of 0.2 g gelatin and 0.3 g hardening agent H-1 per m ² . Samples of this are exposed behind a gradient wedge and processed using the Ektacolor RA4 process.

The sensitometric results are shown in Table 2.

Table 2

The results show that high sensitivity, low fog and at the same time steep gradation (γ ₁ and γ ₂ ) can only be obtained with a combination of ripening agents which comprises ripening agents according to the invention.

Comparative compounds used in the examples:

Claims (11)

1. Spectrally sensitized photographic silver halide emulsion, characterized in that it is obtained by adding at least one compound of the formula I.
wherein R _{1 is} hydrogen, alkyl, alkoxycarbonyl, carbamoyl, carbimidoyl, sulfolanyl, sulfonyl, sulfamoyl, aryl or hetaryl and R ₂ , R _{3 are} hydrogen, alkyl, alkoxycarbonyl, aryl or hetaryl, and wherein R ₂ and R _{3 may be the} same or different, or together may form a 5 to 7-membered carbocyclic ring, a pyrrole ring or a thiophene ring, except in the case of a 6-membered carbocyclic ring, a benzoid ring is matured. 2. Silver halide emulsion according to claim 1, characterized in that the compound of formula I is used in an amount of 10 ^-8 to 10 ^-3 mol / mol Ag. 3. Silver halide emulsion according to claim 1, characterized in that it too at least 50% of the projected tabular crystal area with a Aspect ratio of at least 3 exists.   4. 1-aminoimidazole-2-selenones of the formula I.
wherein R _{1 is} hydrogen, alkyl, alkoxycarbonyl, carbamoyl, carbimidoyl, sulfolanyl, sulfonyl, sulfamoyl, aryl or hetaryl and R ₂ , R _{3 are} hydrogen, alkyl, alkoxycarbonyl, aryl or hetaryl, and wherein R ₂ and R _{3 may be the} same or different, or together may form a 5- to 7-membered carbocyclic ring, a pyrrole ring or a thiophene ring, except in the case of a 6-membered carbocyclic ring, a benzoid ring is excluded. 5. Color photographic silver halide material, characterized in that it contains a silver halide emulsion according to claim 1.