DE19734184A1 - Photographic material stabilised against fog - Google Patents

Abstract

A photographic silver halide (AgX) material containing a light-sensitive AgX emulsion layer comprises a imidazo1,2-ylpyridine of formula: (I); (Where: R1 = hydrogen (H), halogen, sulfo, alkoxy, aryloxy or optionally substituted alkyl; R2 = H, mercapto or an optionally substituted alkylmercapto, alkoxy or alk(en)yl group; or R1 and R2 = a group completing a 5-6-membered ring; R3 = a substituent; m = 0-4).

Description

The invention relates to a silver halide photographic material based on a Carrier has at least one light-sensitive silver halide emulsion layer, whose silver halide is stabilized with a new type of stabilizer.

To stabilize silver halide emulsions against unwanted fog A large number of compounds have already been proposed (Research Disclosure 37254, Part 3 (1995), p. 86 ff and Research Disclosure 37038, Part XV (1995), p. 89 ff). The known stabilizers do not yet adequately fulfill the stated task, especially with highly sensitive silver halide emulsions, e.g. B. with such a share of AgBr from 80 to 99 mol% and of AgI from 1 to 20 mol% and whole especially those that have matured with selenium or tellurium compounds.

The object of the invention was to find stabilizers suitable for such silver halide emulsions to provide sensors.

It has now been found that this object is achieved with certain imidazopyridines can be.

The invention therefore relates to a photographic silver halide material, in particular a color photographic silver halide material and particularly preferably a color negative film with a support and at least one light-sensitive silver halide emulsion layer, characterized in that the light-sensitive silver halide emulsion of this layer is coated with a compound of the formula (I)

wherein
R _{1 is} hydrogen, halogen, sulfo, alkoxy, aryloxy, N-alkylsulfonamido, N-arylsulfonamido or optionally substituted alkyl,
R _{2 is} hydrogen, mercapto, optionally substituted alkylmercapto, optionally substituted alkoxy, optionally substituted alkyl or optionally substituted alkenyl, or
R ₁ and R ₂ together form the remaining members of a 5- to 6-membered ring,
R _{3 is} a substituent and
m is a number from 0 to 4.

Alkyl groups R ₁ and R ₂ , alkyl mercapto R ₂ , alkoxy R ₂ and alkenyl R ₂ can be replaced by halogen, sulfo, optionally substituted phenyl, -COR ₄ , -CO ₂ R ₄ , -OCOR ₄ , -OCO ₂ -R ₄ , - OCON (R ₄ ) R ₅ , -SO ₂ R ₄ , -SR ₄ , -SSR ₄ , -SOR ₄ , -P (O) (OR ₄ ) ₂ , -OP (O) (OR ₄ ) ₂ , -PH (O) OR ₄ , -PR ₄ (O) (OR ₄ ), -P (O) N (R ₄ ) ₂ , -N (R ₄ ) ₂ , -N (R ₄ ) COR ₄ , -OR ₄ , -SO ₂ NHR ₄ may be further substituted, where R _{4 is} an optionally substituted alkyl or phenyl radical or the radical of an imidazopyridine of the formula I.

R ₃ is preferably hydrogen, halogen, optionally substituted alkyl, aryl, alkoxy, aryloxy, alkylthio, arylthio, alkylamido, arylamido, N-alkylcarboxamido, N-arylcarboxamido, N-alkylsulfamoyl, N-arylsulfamoyl, alkylsulfonamido, arylsulfonamido, ureido, Alkylsulfonyl, arylsulfonyl, alkylcarbonyl, arylylcarbonyl, amino, phosphono, hydroxyl, cyano, nitro and mercapto or sulfo.

Preferably mean
R _{1 is} hydrogen or optionally substituted alkyl,
R _{2 is} hydrogen, optionally substituted alkyl or optionally substituted alkenyl,
R _{3 is} hydrogen, optionally substituted alkyl, optionally substituted alkenyl, sulfo, nitro or halogen and
m 0 to 2.

The compounds of formula (I) are preferably used in an amount of 5 to 1000 µmol / mol silver halide used.

Examples of compounds of the formula (I) according to the invention are

The compounds of the formula (I) can be prepared according to the method described by J. Lombardino in J. Chem. Soc. Process described in 2403 (1965).

Synthesis of compound I-1

188 g (2 mol) of 2-aminopyridine and 480 g of 40% strength by weight chloroacetaldehyde solution are added to a mixture of 400 ml of water and 1.6 l of ethanol. Then 204 g (2.4 mol) of NaHCO _{3 are} added and the reaction solution is heated to boiling for 4 hours. The dark solution is evaporated and the residue extracted with diisopropyl ether. The combined diisopropyl ether fractions are dried over Na ₂ SO ₄ , filtered and the solvent is removed on a rotary evaporator. The residue is purified by distillation in a high vacuum.

Imidazo [1,2-a] pyridine is obtained.

10.5 g (0.176 mol) of glacial acetic acid are mixed at 0 ° C. with 5.7 g of 37% strength by weight formaldehyde solution. Then 9.3 g (0.082 mol) of diisobutylamine and 8 g (0.075 mol) of imidazo [1,2-a] pyridine are added and the mixture is stirred at 50 ° C. for three hours. After cooling, 10% by weight sodium hydroxide solution was added and the mixture was extracted several times with diisopropyl ether. The combined ether fractions are dried over Na ₂ SO ₄ and then filtered. After the solvent has been distilled off, the residue is recrystallized from petroleum ether. Yield: 72.5% based on imidazo [1,2-a] pyridine, mp: 58 ° C.

The photographic materials used are black and white negative and reversal films, Black and white paper, X-ray materials, but especially color photographic mate rialien into consideration.

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 light sensitive silver halide emulsion layer is applied. Are suitable as carriers especially thin films and foils. An overview of carrier materials and on the front and back of the auxiliary layers applied is in Research Disclosure 37254, Part 1 (1995), p. 285. The back layer can also be magnetic Contain particles.

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 arranged differently. This is shown for the most important products:
Color photographic films such as color negative films and color reversal films have 2 or 3 red-sensitive, blue-green 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 on the support in the following order. The layers of the same spectral sensitivity differ in their photographic sensitivity, with the less sensitive partial layers generally being arranged closer to the support than the higher sensitive partial layers.

There is usually one between the green-sensitive and blue-sensitive layers Yellow filter layer attached, which prevents blue light from penetrating into the one below Layers.

The possibilities of different layer arrangements and their effects the photographic properties are described in J. Int. Rec. Mats., 1994, Vol. 22, pages 183-193 described.  

Color photographic paper, which is usually much less sensitive to light than one color photographic film, shows in the following order Carriers usually each have a blue-sensitive, yellow-coupling silver halide emulsion layer, a green sensitive, purple coupling silver halide emulsion layer and one red-sensitive, cyan-coupling silver halide emulsion layer; 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 can be high sensitive layers to form a layer package and all low-sensitivity layers another layer package can be summarized in a photographic film in order to Increase sensitivity (DE 25 30 645).

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.

Information about suitable silver halide emulsions, their preparation, maturation, stabilization lization with other than the inventive stabilizers and spectral Sensitization, including suitable spectral sensitizers, can be found in Research Disclosure 37254, Part 3 (1995), p. 286 and in Research Disclosure 37038, Part XV (1995), p. 89.

Photographic materials with camera sensitivity usually contain silver bromide iodide emulsions, which may also contain small amounts of silver chloride can. 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 and in Research Disclosure 37038, Part II (1995), p. 80. The maximum Absorption of those formed from the couplers and the color developer oxidation product Dyes are preferably in the following ranges: yellow coupler 430 to 460 nm, Purple couplers 540 to 560 nm, cyan couplers 630 to 700 nm.

Color photographic films are used to improve sensitivity, graininess, Sharpness and color separation are often used when reacting with the compounds Develop oxidation product release compounds that are photographically active, 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 and in Research Disclosure 37038, Part XIV (1995), p. 86.

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) emulsifies and lie after drying the layers as fine droplets (0.05 to 0.8 µm diameter) in the layers in front.

Suitable high-boiling organic solvents, methods for incorporation into the Layers of photographic material and other methods, chemical compounds to be incorporated 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 another light-sensitive layer with different spectral sensitization prevent.  

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

The photographic material can also contain UV light-absorbing compounds, white toners, spacers, filter dyes, formalin scavengers, light stabilizers, antioxidants, D _Min dyes, additives to improve the stability of dyes, couplers and whites and 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 and in Research Disclosure 37038, Parts IV, V, VI, VII, X, XI and XIII (1995), p. 84 ff.

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

Suitable hardener substances can be found in Research Disclosure 37254, Part 9 (1995), p. 294 and in Research Disclosure 37038, Part XII (1995), page 86.

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 and in Research Disclosure 37038, parts XVI to XXIII (1995), p. 95 ff. published together with exemplary materials.

example 1

A tabular AgBrI emulsion with 4 mol% AgI, an average diameter of the same area of 0.9 µm and an aspect ratio of 6: 1, which was ripened optimally with carbon tetrachloride, potassium thiocyanate and sodium thiosulfate, was red-sensitized with 290 µmol sensitizer dye per mol silver halide and with the Amounts of comparative stabilizer 1 or compounds of the invention given in the table below. An emulsion of a cyan coupler was added to the emulsion and an amount corresponding to 2.8 g AgNO ₃ / m ^{2 was applied} to a 100 μm thick substrate made of cellulose triacetate and coated with a hardening layer and hardened.

The individual samples were exposed to daylight behind an orange filter and in each case a graduated gray wedge and then processed according to the process described in "The British Journal of Photography" 1974, p. 597. The sensitivities are determined after densitometric measurement at a density of 0.2 over D _min in relative DIN units. The veil is also determined in relative units.

Table 1

Comparative stabilizer 1

Example 2

Corresponds to example 1 with the following changes:
The AgI content was 8 mol%; the average diameter is 1.1 µm; the aspect ratio 4: 1. The silver halide emulsion was sensitized with 450 μmol green sensitizer per mole silver halide and admixed with a purple coupler. The results are shown in Table 2.

Table 2

Example 3

Corresponds to example 1 with the following changes:
The AgI content was 3 mol%; the mean diameter 0.8 µm; the aspect ratio 8: 1. The results are shown in Table 3.

Table 3

Example 4

Corresponds to example 2 with the following changes:
The AgI content was 3 mol%; the mean diameter 0.6 μm, the aspect ratio 6.5: 1. The results are shown in Table 4.

Table 4

Example 5

Corresponds to example 1 with the following changes:
The AgI content was 5 mol%; the mean grain diameter 0.9 µm; the aspect ratio 4.5: 1. The results are shown in Table 5.

Table 5

Claims (3)

1. Photographic silver halide material with a support and and at least one light-sensitive silver halide emulsion layer, characterized in that the light-sensitive silver halide emulsion of this layer contains a compound of formula (I)
wherein
R _{1 is} hydrogen, halogen, sulfo, alkoxy, aryloxy or optionally substituted alkyl,
R ^{2 is} hydrogen, mercapto, optionally substituted alkylmercapto, optionally substituted alkoxy, optionally substituted alkyl or optionally substituted alkenyl or
R ₁ and R ₂ together form the remaining members of a 5- to 6-membered ring,
R _{3 is} a substituent and
m is a number from 0 to 4. 2. Photographic silver halide material according to claim 1, characterized in that
R ^{1 is} hydrogen or optionally substituted alkyl,
R ^{2 is} hydrogen, optionally substituted alkyl or optionally substituted alkenyl,
R ^{3 is} hydrogen, optionally substituted alkyl, optionally substituted alkenyl, sulfo, nitro or halogen and
m is 0 to 2. 3. Photographic silver halide material according to claim 1, characterized records that the compound of formula (I) in an amount of 5 to 1000 µmol / mol silver halide is used.