DE19617767A1 - High sensitivity, low fog silver halide colour photographic material - Google Patents

Abstract

A colour-photographic copying material (eg colour negative paper) with blue-, green- and red-sensitive Ag halide emulsion layers in which the halide is more than 95 mol.% AgCl is such that at least one emulsion layer ripened with an Au compound and with an S and/or Se compound contains a thioether of formula (I) and is spectrally sensitised with a sensitising dye of formula (II). In the formulae, R1 = alkyl, alkenyl, cycloalkyl, aryl or aralkyl with up to 8C; R2 - R5 = H or alkyl with up to 3C or together are members of a 5- or 6-membered ring; R6 = H or a substituent; L1 = alkylene chain of 2-4C with a 2 or 3C chain length; X = O or S; R8 and R13 = Cl, CN, phenyl or aromatic heterocycle residue; R7, R9, R12 and R14 = H, or adjacent R -R9 or R12-R14 together form a condensed benzene of naphthalene ring; R10 and R11 = sulpho-2-4C alkyl or carboxy-2-4C alkyl; L2 = =C- or -CH=C(Et)-CH=; and M<+> = a cation.

Description

The invention relates to a color photographic copying material with increased sensitivity lightness, steep gradation and low veil.

Color photographic copying materials, e.g. B. color negative paper contain at least a blue sensitive silver halide emulsion containing a yellow coupler layer, at least one green-sensitive silver containing a purple coupler halide emulsion layer and at least one red-sensitive, one teal coupler-containing silver halide emulsion layer, the silver halide emulsion ions consist of more than 95 mol% of AgCl and which have a steep gradation have.

To give these silver halide emulsions a high sensitivity to light hen, they are on the one hand with gold and on the other hand with sulfur and / or Matured selenium compounds.

A further increase in sensitivity can be achieved by adding certain Thioethers can be achieved (EP-A-5804). The addition of these thioethers results in generally to an undesirable increase in the veil.

The object of the invention was to lower this veil without sacrificing Accept sensitivity and gradation.

This problem is solved by using certain spectral sensitizers.

The object of the invention is therefore a color photographic silver halide copy material of the type mentioned, characterized in that at least one Silver halide emulsion layer a silver halide emulsion with at least Contains 95 mol% AgCl, on the one hand with gold and on the other hand with sulfur and / or Selenium compounds has matured, contains a thioether of formula (I)

wherein
R₁ is an alkyl, alkenyl, cycloalkyl, aryl or aralkyl radical with not more than 8 carbon atoms,
R₂ to R₅ H or alkyl with not more than 3 carbon atoms or in pairs the members of a five or six ring,
R₆ is hydrogen or a substituent and
L₁ is an alkylene chain with 2 to 4 carbon atoms and a chain length of 2 or 3 carbon atoms and
with a sensitizer dye of formula (II)

wherein
XO or S,
R₈ and R₁₃ Cl, CN, phenyl or the rest of an aromatic heterocycle and
R₇, R₉, R₁₂ and R₁₄ are hydrogen or
two adjacent radicals R₇, R₈ and R₉ or R₁₂, R₁₃ and R₁₄ together form a fused benzene ring or naphthalene ring,
R₁₀ and R₁₁ represent a sulfoalkyl or carboxyalkyl group with 2 to 4 carbon atoms in the alkyl part,

L₂ -CH = or

and
M⊕ is a cation which may be necessary for charge balancing,
is spectrally sensitized.

On the one hand, preferred are sensitizer dyes of the formula II in which X S and L₂ -CH = and sensitizer dyes of the formula II in which X O and L₂ -CH = C (C₂H₅) -CH = mean.

Suitable heterocyclic aromatic radicals R₈ or R₁₃ are z. B. 1-pyrrolyl and 2-thenyl.

Suitable radicals L₁ are ethylene, 1,2-propylene, 1,3-propylene, 1,2-butylene and 2,3-butylene residues.

The silver halide emulsion layer is e.g. B. a green sensitive or preferably blue-sensitive layer.

The compound of formula (I) is used especially in an amount of 5 to 500 mg / kg silver of the silver halide in question is used.

The silver halide emulsions of the material according to the invention contain maximum at least 2 mol% AgI and are in particular iodide-free.

The compounds of formula (I) are particularly during the precipitation of the Maturation or spectral sensitization added.

Within formula (I), compounds are preferred in which
R₆ is H, an alkyl, alkenyl or cycloalkyl group with not more than 6 carbon atoms, an acyl, alkoxycarbonyl, carbamoyl or sulfonyl group and the compounds contain no more than 15 carbon atoms.

Suitable compounds of the formula (I) are:

A particularly preferred compound is I-9.

Suitable sensitizers of formula II are:

The emulsions according to the invention can be with acidic NH or SH compounds gene stabilized in a known manner. The stabilizers are preferred added after ripening and selected so that they sensitize dye, or the sensitizing dyes not from the emulsion grains Silver chloride emulsion displace and also the bleaching of the image silver in the Do not hinder the processing.

Ripening with sulfur is preferably carried out with sodium thiosulfate as ripening medium, but also thioureas or isothiocyanates or thiophosphates can be used as a sulfur ripening agent.

The ripening with selenium is preferably carried out with selenium ureas that have at least are trisubstituted with heterocyclic selenones that do not become a selenolate ion can be deprotonated, or with phosphane selenides, preferably with Triarylphosphane selenides.

The ripening with gold is preferably carried out with gold (III) chloride or a tetra chloroaurate (III) salt that reduces to a gold (I) compound as it ripens becomes. This can e.g. B. caused by the added bisthioether. Will the Thioether added together with the gold (III) salt, then the bisthioether presumably reduced as a ligand to a gold (I) thioether sulfoxide complex. The Formation of gold (I) thioether sulfoxide complexes from bisthioethers and gold (III) salt is known in the literature. It can be assumed that with comparable nucleophilicity neither of the two sulfur atoms in the bisthioether is preferred.

Sulfur and / or selenium ripening on the one hand and gold ripening on the other hand can done together or sequentially.

The emulsions can also be doped in the form of other noble metals contain connections to set the desired gradation or a  desired latent image behavior, or a desired of reciprocity largely lack free development behavior during or after the precipitation of silver chloride are added. This affects e.g. B. Rhodium salts (III) or iridium (III). The emulsions can also be doped with hexacyano contain ferrate (II).

The emulsions can also palladium (II) compounds, in particular Tetrachloropalladate (II) contain, which should improve the long-term stability.

The emulsions can also be used to lower the fog Isothiazolone or isoselenazolone compounds, or disulfides or diselenides contain. For setting a reciprocity-free development, above all a stable gradation regardless of the exposure time, the Emul ions also contain alkali or ammonium tetrathionates.

Chemical ripening with sulfur or selenium compounds and gold and spectral sensitization can be done separately or in one step will.

The photographic copying materials consist of a support on which at least one photosensitive silver halide emulsion layer is applied. Thin films and foils are particularly suitable as supports. An overview of Backing materials and those applied to their front and back Auxiliary layers are shown in Research Disclosure 37254, Part 1 (1995), p. 285.

The color photographic copying materials usually contain at least each a 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 illustrated using the example of color negative paper:
Color photographic paper, which is generally much less sensitive to light than a color photographic film, usually has 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 support in the order given below Yellow filter layer can be omitted.

Deviations in the number and arrangement of the photosensitive layers can occur to achieve certain results. For example, you can all highly sensitive layers in one layer package and all low sensitivity layers to another layer package in a photographic film be summarized to increase the 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 and spectral sensitization including suitable spectrals sensitizers can be found in Research Disclosure 37254, Part 3 (1995), pp. 286 and in Research Disclosure 37038, Part XV (1995), p. 89.

Photographic copying materials preferably contain silver chloride bromide emulsion with more than 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 that from the couplers and the color developer oxide dyes formed product is preferably in the following areas: Yellow coupler 430 to 460 nm, purple coupler 540 to 560 nm, cyan coupler 630 up to 700 nm.

Mostly hydrophobic color couplers, but also other hydrophobic components of the layers, are usually in high-boiling organic solvents dissolved or dispersed. These solutions or dispersions are then in one emulsified aqueous binder solution (usually gelatin solution) and lie after drying the layers as fine droplets (0.05 to 0.8 µm through knife) in the layers.  

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

The usually between layers of different spectral sensitivity arranged non-light-sensitive intermediate layers can contain agents which an undesirable diffusion of developer oxidation products from a photosensitive to another photosensitive layer with different prevent spectral sensitization.

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, whiteners, spacers, filter dyes, formalin scavengers, light stabilizers, antioxidants, D _min dyes, additives to improve the stability of dyes, couplers and whites as well as to reduce the color fog, plasticizers (latices), Contain biocides and others.

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, M and XIII (1995), p. 84 ff.

The layers of color photographic materials are typically hardened, i.e. H., the binder used, preferably gelatin, is by suitable cross-linked chemical processes.

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 imagewise exposure, color photographic materials become their character ter processed according to different processes. Details of the 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.

Preparation of the emulsions

The following solutions with demineralized water are prepared:
Solution 1:
7000 ml of water
540 g gelatin
Solution 2:
7000 ml of water
1300 g sodium chloride
Solution 3:
7000 ml of water
3000 g silver nitrate

Emulsion A: (comparison)

Solutions 2 and 3 are at 60 ° C for 120 minutes at a pAg of 7.7 was simultaneously added to solution 1 with vigorous stirring. It will be one Silver chloride emulsion with an average particle diameter of 0.8 µm receive. The weight ratio of gelatin to silver is 0.18. The Emulsion is flaked in a known manner, washed and with as much gelatin redispersed that the gelatin / silver weight ratio is 0.56. The emulsion contains 1 mole of silver chloride per kg.

Then at pH 4.5 with 3.5 µmol KAuCl₄ and 1.5 µmol Na₂S₂O₃ pro mol Ag optimally matured at 60 ° C.

After chemical ripening, the emulsion becomes the blue with 300 µmol sensitizer V-1 spectrally sensitized and with 280 µmol 1- (3-acetamino phenyl) -5-mercaptotetrazole stabilized.

Emulsion B: (comparison)

The emulsion is prepared like emulsion A, but with the difference that the solution 1 contained 0.05 g of 1,8-dihydroxy-3,6-dithiaoctane per mole of AgNO₃.

Emulsion C: (comparison)

The emulsion is prepared like emulsion A, but with the difference that the solution 1 contained 0.07 g of compound I-9 per mole of AgNO₃.

Emulsion D: (comparison)

The emulsion is prepared like emulsion A, but with the difference that after precipitation in the absence of a thioether and ripening with gold 300 µmol of sensitizer II-1 are added.  

Emulsion E: (comparison)

The emulsion is prepared like emulsion B, but with the difference that after precipitation in the presence of 1,8-dihydroxy-3,6-dithiaoctane and ripening with gold 300 µmol of the sensitizer II-I are added.

Emulsion F: (invention)

The emulsion is prepared like emulsion A, but with the difference that Solution 1 contains 0.07 g of compound I-9 and the flaked and gold-ripened Emulsion is sensitized with 300 µmol of sensitizer II-1.

Emulsions A-F are each mixed with an emulsifier of a yellow coupler Trikresylphosphat added and on a support from both sides with Polyethylene coated paper applied.

The cast individual layers contain per m²:
0.63 g AgNO₃,
1.38 g gelatin,
0.95 g yellow coupler V2,
0.29 g tricresyl phosphate.

The material is made by applying a protective layer to 0.2 g of gelatin and 0.3 g of instant hardener (V-3) hardened per m². Samples of it become pictorial exposed behind a gradient wedge and after the Ektacolor RA-4 process processed.

The sensitometric results are shown in Table 1:  

Table 1

The results show that the desired properties, namely high sensitivity with low fog only with the invention Combination of thioether 1-9 gold ripening and use of the sensitizer II-1 is reached.

When using thioethers not according to the invention, e.g. B. the 1,8-dihydroxy-3,6- dithiaoctans, on the other hand, consistently high minimum densities are obtained.

If a sensitizer not according to the invention is used, fog is produced poor casts can only be obtained without thioether, but the required sensitivity nowhere near reached.

Blocks used:

Claims (5)

1. Color photographic silver halide copying material containing at least one blue-sensitive silver halide emulsion layer containing at least one yellow coupler, at least one green-sensitive silver halide emulsion layer containing at least one magenta coupler and at least one red-sensitive silver halide emulsion layer containing at least one cyan coupler, the silver halide emulsions of which consist of more than 95 mol% of AgCl characterized in that at least one silver halide emulsion layer is ripened on the one hand with gold and on the other hand with sulfur and / or selenium compounds, contains a thioether of the formula (I) wherein
R₁ is an alkyl, alkenyl, cycloalkyl, aryl or aralkyl radical with not more than 8 carbon atoms,
R₂ to R₅ H or alkyl with not more than 3 carbon atoms or in pairs the members of a five or six ring,
R₆ is hydrogen or a substituent and
L₁ is an alkylene chain with 2 to 4 carbon atoms and a chain length of 2 or 3 carbon atoms and
with a sensitizer dye of formula (II) wherein
XO or S,
R₈ and R₁₃ Cl, CN, phenyl or the rest of an aromatic heterocycle and
R₇, R₉, R₁₂ and R₁₄ are hydrogen or
two adjacent radicals R₇, R₈ and R₉ or R₁₂, R₁₃ and R₁₄ together form a fused benzene ring or naphthalene ring,
R₁₀ and R₁₁ represent a sulfoalkyl or carboxyalkyl group with 2 to 4 carbon atoms in the alkyl part,
L₂ -CH = or and
M⊕ is a cation which may be necessary for charge balancing,
is spectrally sensitized. 2. Color photographic silver halide material according to claim 1, characterized characterized in that X is O and L₂ -CH = C (C₂H₅) -CH =. 3. Color photographic silver halide material according to claim 1, characterized characterized in that X S and L₂ -CH =. 4. Color photographic silver halide material according to claim 1, characterized in that
R₆ is H, an alkyl, alkenyl or cycloalkyl group with no more than 6 carbon atoms, an acyl, alkoxycarbonyl, carbamoyl or sulfonyl group and the compounds of the formula (I) contain no more than 15 carbon atoms. 5. Color photographic silver halide material according to claim 1, characterized characterized in that the compound of formula I in an amount of 5 to 500 mg / kg silver of the silver halide in question is used.