EP0158261B1 - Photographic recording material - Google Patents

Description

The invention relates to a highly sensitive color photographic recording material having a plurality of silver halide emulsion layers, in which an improved granularity is achieved.

It is known to use recording materials for the production of colored photographic images which each carry a red-sensitive, a green-sensitive and a blue-sensitive silver halide emulsion layer on a layer support, each of the silver halide emulsion layers mentioned containing non-diffusing color couplers for producing the blue-green, the purple and the yellow partial color image and where the color of the partial color image produced is complementary to the spectral sensitivity of the silver halide emulsion layer. Common color photographic materials also include other layers, such as a yellow filter layer between the top blue-sensitive silver halide emulsion layer and the underlying green-sensitive silver halide emulsion layer, and an antihalation layer between the support and the lowermost silver halide emulsion layer. Additional intermediate gelatin layers and a cover layer can also be provided.

It is further known to use such recording materials for the production of color photographic images in which at least two silver halide emulsion layers are provided in each case for producing one or more of the three different partial color images. According to GB-PS 818 687, the lowest light-sensitive color-forming layer unit of a color photographic multilayer material consists of two partial layers sensitized to light of the same spectral range, containing silver halide and color coupler, the upper layer of which has the greater sensitivity. From DT-PS 1 121 470 the use of such double layers of different sensitivity is known, of which the more sensitive gives the lower color density in color development.

Color photographic recording materials with double and triple layers for the different spectral ranges are further known from US Pat. Nos. 3,663,228 and 3,849,138. Here too, the upper of the two partial layers sensitive to light of the same spectral range has the higher sensitivity.

A similar structure is known from US Defensive Publication T 860 004.

According to DT-OS 2 018 341, three silver halide emulsion partial layers of the same spectral sensitivity but different general sensitivity are to be used to improve the granularity of a partial color image, with each more sensitive partial layer being arranged further away from the layer support than any less sensitive partial layer. In addition, a maximum color density of at most 0.6 and a total of at most 1.0 is achieved in the middle and in the upper sub-layer, which can be achieved by reducing the coupler content, i. H. can be achieved by increasing the ratio of silver halide to coupler.

According to DE-OS 2 704 826, a color photographic recording material contains at least three green-sensitive silver halide emulsion partial layers with embedded purple couplers, of which each more sensitive partial layer is arranged further away from the layer support and has a higher ratio of silver halide to coupler than any less sensitive partial layer. This results in an improved sensitivity-graininess ratio.

It is known from DE-OS 2 622 922 to arrange a yellow filter layer between comparatively less red and green sensitive silver halide emulsion layers on the one hand and comparatively more sensitive red and green sensitive silver halide emulsion layers on the other hand. This increases the sensitivity.

From EP-OS 155 814 a photographic material is known in which the blue-sensitive sub-layers are separated by a yellow filter layer without further information for such a material, for. B. about silver / coupler ratios.

From US-A-4 165 236 a photographic material with double layers for the red and green sensitized layers is known, in which for example the red sensitized layers are separated by a yellow filter.

What is unsatisfactory with the known measures for the construction of highly sensitive recording materials is that the granularity is too great with the highest sensitivity or that the desired sensitivity is not achieved with acceptable granularity.

The object of the invention was therefore to provide a highly sensitive material with improved granularity.

It has now been found a photographic recording material with at least one yellow filter layer and at least one blue, green and red sensitive layer, of which at least one layer is split into at least three sub-layers of different sensitivity, these sub-layers being arranged so that the light at Exposure exposes at least one partial layer before it passes through the yellow filter layer and exposes at least one partial layer after it has passed through the yellow filter layer, which is characterized in that - based on at least one layer - the ratio K / A in the most sensitive partial layer is greater than in that next sensitive sublayer. The green- and red-sensitive layers are preferably split into such partial layers. The yellow filter layer preferably has a color density of at least 0.2, especially 0.25-0.6.

K is understood to mean the molar amount of the color-forming couplers contained in the respective partial layer and A is the molar amount of the light-sensitive silver halide contained in the respective partial layer. The molar amount of the color-imparting coupler must be calculated on the condition that the coupler is a 4-equivalent coupler; If, for example, a 2- or 6-equivalent coupler is used, corresponding conversions must be carried out. Coloring couplers are understood to mean the usual color couplers, mask couplers and color coupling DIR connections.

At the same time, the maximum color density of the most sensitive sublayer is preferably limited by the fact that its silver application is lower than that of the next lower sensitive sublayer, or by the fact that the highly sensitive sublayer contains a slow DIR coupler, which has the color density but not the sensitivity of the developed layer influenced.

In a preferred embodiment, the sub-layers of at least one layer are arranged such that the imagewise exposure exposes the highly sensitive green or red-sensitive sub-layer before the light passes through the yellow filter and the two least sensitive sub-layers are exposed after the light has passed the yellow filter .

• 1. wenigstens zwei rotempfindliche Teilschichten,
• 2. wenigstens zwei grünempfindliche Teilschichten,
• 3. eine Gelbfilterschicht,
• 4. wenigstens eine rotempfindliche Teilschicht,
• 5. wenigstens eine grünempfindliche Teilschicht,
• 6. wenigstens eine blauempfindliche Schicht

wobei die Empfindlichkeit von Teilschichten gleicher spektraler Empfindlichkeit um so höher ist, je weiter sie vom Schichtträger entfernt ist. In einer bevorzugten Ausführungsform können die über dem Gelbfilter liegenden rot- und grünempfindlichen Teilschichten vertauscht sein.In a particularly preferred embodiment, the following layers are arranged on a carrier in the order given:

• 1. at least two red-sensitive sub-layers,
• 2. at least two green-sensitive sub-layers,
• 3. a yellow filter layer,
• 4. at least one red-sensitive sublayer,
• 5. at least one green-sensitive sublayer,
• 6. at least one blue-sensitive layer

the sensitivity of partial layers of the same spectral sensitivity is higher the further away from the layer support. In a preferred embodiment, the red and green-sensitive sublayers lying over the yellow filter can be interchanged.

In a further preferred embodiment, the recording material contains at least one further yellow filter layer which is arranged such that the light passes through this additional yellow filter layer during the image-wise exposure before it passes through a green- or red-sensitive layer. It preferably contains a binder in which colloidal silver filter yellow or a yellow dye is embedded with a color density of less than 0.2.

The ratio K / A in the red- or green-sensitive sub-layers is in preferred embodiments

• r rotempfindliche Teilschicht, geringe Empfindlichkeit
• R rotempfindliche Teilschicht, mittlere Empfindlichkeit
• RR rotempfindliche Teilschicht, höchste Empfindlichkeit
• g grünempfindliche Teilschicht, geringe Empfindlichkeit
• G grünempfindliche Teilschicht, mittlere Empfindlichkeit
• GG grünempfindliche Teilschicht, höchste Empfindlichkeit.

Here mean:

• r red-sensitive sub-layer, low sensitivity
• R red-sensitive sub-layer, medium sensitivity
• RR red sensitive sub-layer, highest sensitivity
• g green-sensitive sub-layer, low sensitivity
• G green-sensitive sub-layer, medium sensitivity
• GG green sensitive sub-layer, highest sensitivity.

It is also possible to combine approximately equally sensitive layers of different spectral absorption, so that, for. B. on a substrate in the order given - if necessary with intermediate layers and outer layers - are included:

The abbreviations r, R, RR, g, G, GG have the meaning given above. GF stands for yellow filter, B for a medium-sensitive blue-sensitive sublayer and BB for a highly sensitive blue-sensitive sublayer.

When assessing the sensitivity of the individual sub-layers, it is not the absolute sensitivity that is important, but the effective sensitivity, taking into account the respective position within the color photographic multilayer material. The difference in the effective sensitivity is expediently between 0.1 and 1.0 relative log Ixt units. In individual cases, the difference in sensitivity is chosen so that a balanced gradation curve results without perceptible distortion during color photographic processing.

Measures to set a desired sensitivity are known, e.g. B. Change in the silver iodide content, the degree of physical ripening (grain size), the degree of chemical or spectral sensitization or the addition of a desensitizer. Of course, in the interest of the highest possible overall sensitivity, partial layers of medium and low sensitivity should also have the highest possible sensitivity, as long as only the sensitivity relation required according to the invention is maintained.

In addition to the layers already mentioned, further, non-light-sensitive auxiliary layers can be present in the color photographic recording material according to the invention, e.g. B. adhesive layers, antihalation layers or outer layers, in particular intermediate layers between the light-sensitive layers, whereby the diffusion of developer oxidation products from one layer to another is to be effectively prevented. For this purpose, intermediate layers of this type can furthermore contain certain compounds which are able to react with developer oxidation products. Such layers are preferably arranged between adjacent light-sensitive spectral sensitivities. A less sensitive silver halide emulsion with an average grain diameter of about 0.1 J.1.m or smaller, which contains chloride, bromide and optionally iodide, can also be incorporated into these intermediate layers. Such a layer has a particularly beneficial effect on the sensitivity of the adjacent red-sensitive or green-sensitive sub-layers. The less sensitive silver halide emulsion can, however, also be introduced directly into the green- and red-sensitive layers located below the blue-sensitive layers.

Color couplers are assigned to the light-sensitive silver halide emulsion layers, which · react with color developer oxidation products to form a non-diffusing dye. The color couplers are expediently housed in a non-diffusing manner in the light-sensitive layer itself or in close proximity to it.

For example, the red-sensitive layer can contain a non-diffusing color coupler for producing the blue-green partial color image, usually a coupler of the phenol or a-naphthol type. The green-sensitive layer can contain, for example, at least one non-diffusing color coupler for producing the purple partial color image, color couplers of the 5-pyrazolone type usually being used. The blue-sensitive layer can contain, for example, at least one non-diffusing color coupler for producing the yellow partial color image, usually a color coupler with an open-chain ketomethylene grouping. In the color couplers it can be, for. B. to 6-, 4- and 2-equivalent couplers. Suitable couplers are known, for example, from the publications “Color Coupler” by W. Pelz in “Messages from the Research Laboratories of Agfa, Leverkusen / Munich”, Volume 111, page 111 (1961), K. Venkataraman in “The Chemistry of Synthetic Dyes”, Vol. 4, 341 to 387, Academic Press (1971) and TH James, "The Theory of the Photographic Process", 4th Ed., Pp. 353-362, and from Research Disclosure No. 17643 of December 1978, Section VII, published by Industrial Opportunities Ltd., Homewell Havant, Hampshire, P09 1 EF in the UK.

The recording material can also contain DIR compounds and the so-called white couplers, which do not give any dye when reacted with color developer oxidation products. DIR compounds are understood to mean those compounds which, when reacted with color developer oxidation products, release diffusing organic compounds which inhibit the development of silver halide. The inhibitors can be eliminated directly or via non-inhibiting intermediates. Reference is made to GB 953 454, US 3,632,345, US 4,248,962 and GB 2,072,363.

In a particularly preferred embodiment, at least two sub-layers are assigned to a layer of DIR compounds of different reactivity and color coupler that is sensitive to the same spectral range. The ratio of the effective reaction rate constants of the color coupler and the DIR compound in the more sensitive sub-layer is larger than in the less sensitive sub-layer. The effective reaction rate constant can be determined electrochemically by the method known from DE-OS 2 853 632 and US 4,315,070. The ratio of the effective reaction rate constants in the more sensitive sublayer is preferably between 2: 1 and 20: 1 and the ratio of the reaction rate constants of Color couplers and DIR connections of the less sensitive partial layer are preferably between 0.03: 1 and 6: 1.

The light-sensitive silver halide emulsions used can contain chloride, bromide and iodide or mixtures thereof as the halide. In a preferred embodiment, the halide content of at least one layer consists of 0 to 10 mol% of Agl, 0 to 50 mol% of AgCl and 50 to 100% of AgBr, the sum of these proportions being 100%.

In a preferred embodiment, it is predominantly compact crystals, the z. B. are cubic or actohedral or have transitional forms. They can be characterized in that they essentially have a thickness of more than 0.2 .mu.m. The average ratio of diameter to thickness is preferably less than 8: 1, it being true that the diameter of a grain is defined as the diameter of a circle with a circle content corresponding to the projected area of the grain.

In another preferred embodiment, all or individual emulsions can also have essentially tabular silver halide crystals in which the ratio of diameter to thickness is greater than 8: 1.

The emulsions can be chemically sensitized. The usual sensitizers are suitable for chemical sensitization of the silver halide grains. Sulfur-containing compounds, for example allyl isothiocyanate, allyl thiourea and thiosulfates, are particularly preferred. Reducing agents, e.g. B. the tin compounds described in Belgian patents 493 464 or 568 687, further polyamines such as diethylenetriamine or aminomethylsulfinic acid derivatives, for. B. according to Belgian patent 547 323 used. Precious metals or noble metal compounds such as gold, platinum, palladium, iridium are also suitable as chemical sensitizers. Ruthenium or rhodium. This method of chemical sensitization is described in the article by R. Koslowsky, Z. Wiss. Phot. 46, 65-72 (1951). It is also possible to sensitize the emulsions with polyalkylene oxide derivatives, e.g. B. with polyethylene oxide having a molecular weight between 1,000 and 20,000, also with condensation products of alkylene oxides and aliphatic alcohols, glycols, cyclic dehydration products of hexitols, with alkyl-substituted phenols, aliphatic carboxylic acids, aliphatic amines, aliphatic diamines and amides. To achieve special effects, these sensitizers can of course be used in combination, as described in Belgian patent 537 278 and British patent 727 982. Reference is also made to Research Disclosure No. 17643, section III.

The emulsions can be optically sensitized in a manner known per se, e.g. B. with the usual polymethine dyes such as neutrocyanines, basic or acidic carbocyanines, rhodacyanines, hemicyanines, styryl dyes, oxonols and the like. Such sensitizers are described by F. M. Hamer in “The Cyanine Dyes and related Compounds •, (1964). In this regard, reference is made in particular to Ullmann's Encyclopedia of Industrial Chemistry, 4th edition. Volume 18, pages 431 ff and on the above-mentioned Research Disclosure No. 17643, Section IV.

The commonly used antifoggants and stabilizers can be used. Particularly suitable stabilizers are azaindenes, preferably tetra- or penta-azaindenes, in particular those which are substituted by hydroxyl or amino groups. Such connections are e.g. B. in the article by Birr, Z. Wiss. Phot. 47, (1952), pp. 2-58. Other suitable stabilizers and antifoggants are given in Research Disclosure No. 17643 above in Section IV.

The components of the photographic material can be incorporated using customary, known methods. If the compounds are soluble in water or alkali, they can be added in the form of aqueous solutions, optionally with the addition of water-miscible organic solvents such as ethanol, acetone or dimethylformamide. If they are insoluble in water or alkali, they can be incorporated into the recording materials in dispersed form in a manner known per se. For example, a solution of these compounds in a low-boiling organic solvent can be mixed directly with the silver halide emulsion or initially with an aqueous gelatin solution and the organic solvent can then be removed. The dispersion of the respective compound thus obtained can then be mixed with the silver halide emulsion. If necessary, so-called oil formers are also used, generally higher-boiling organic compounds, which include the compounds to be dispersed in the form of oily droplets. In this connection, reference is made, for example, to US Pat. Nos. 2,322,027, 2,533,514, 3,689,271, 3,764,336 and 3,765,897. It is also possible to include components of the photographic material, e.g. B. to install couplers and UV absorbers in the form of loaded latices, see DE-OS 2 541 274 and EP-A 14 921. Furthermore, the constituents can also be defined as polymers in the material, see, for. B. DE-OS 2 044 992, US 3 370 952 and US 4 080 211.

The usual substrates can be used for the materials according to the invention, e.g. B. carriers made of cellulose esters, for. B. cellulose acetate and polyester. Also suitable are paper supports, which can optionally be coated, for. B. with polyolefins, especially with polyethylene or polypropylene. In this regard, reference is made to Research Disclosure No. 17643 section XVII indicated above.

The usual hydrophilic film-forming agents are suitable as protective colloid or binder for the layers of the recording material, e.g. B. proteins, especially gelatin, alginic acid or their derivatives such as esters, amides or salts, cellulose derivatives such as carboxymethyl cellulose and cellulose sulfates, starch or their derivatives or hydrophilic synthetic binders such as polyvinyl alcohol, partially saponified polyvinyl acetate, polyvinyl pyrrolidone and others. In a mixture with the hydrophilic binders, the layers can also contain other synthetic binders in dissolved or dispersed form, such as homopolymers or copolymers of acrylic or methacrylic acid or their derivatives, such as esters, amides or nitriles, and also vinyl polymers, such as vinyl esters or vinyl ethers. Reference is also made to the binders specified in Research Disclosure 17643 above in Section IX.

The layers of the photographic material can be hardened in the usual manner, for example with hardeners of the epoxy type, the heterocyclic ethylene imine and the acryloyl type. Furthermore, it is also possible to harden the layers in accordance with the process of German laid-open specification 2 218 009 in order to obtain color photographic materials which are suitable for high-temperature processing. It is also possible to harden the photographic layers or the color photographic multilayer materials with hardeners of the diazine, triazine or 1,2-dihydroquinoline series or with hardeners of the vinyl sulfone type. Further suitable hardening agents are known from German laid-open documents 2 439 551, 2 225 230, 2 317 672 and from Research Disclosure 17643, section XI, specified above.

Further suitable additives are given in Research Disclosure 17643 and in “Product Licensing Index of December 1971, pages 107-110.

Suitable color developer substances for the material according to the invention are in particular those of the p-phenylenediamine type, e.g. B. 4-amino-N, N-diethyl-aniline hydrochloride 4-amino-3-methyl-N-ethyl-N-ß- (methanesulfonamido) ethylaniline sulfate hydrate; 4-amino-3-methyl-N-ethyl-N-β-hydroxyethylaniline sulfate; 4-amino-N-ethyl-N- (2-methoxyethyl) -m-toluidine-di-p-toluenesulfonic acid and N-ethyl-N-ß-hydroxyethyl-p-phenylenediamine. Other useful color developers are described, for example, in J. Amer. Chem. Soc. 73, 3100 (1951) and in G. Haist, Modern Photographic Processing, 1979, John Wiley and Sons, New York, pages 545 ff.

After color development, the material is usually bleached and fixed. Bleaching and fixing can be carried out separately or together. The usual compounds can be used as bleaching agents, e.g. B. Fe ^{3 +} salts and Fe ^{3 + -} complex salts such as ferricyanides, dichromates, water-soluble cobalt complexes, etc. Particularly preferred are iron III complexes of aminopolycarboxylic acids, especially z. B. ethylenediaminetetraacetic acid, nitrilotriacetic acid, lminodiacetic acid, N-hydroxyethylethylenediaminetriacetic acid, alkyliminodicarboxylic acids and corresponding phosphonic acids. Persulphates are also suitable as bleaching agents.

Examples

In the following examples, the couplers used are referred to as follows
(See formulas on page 7 ff.)

Example 1 (Invention)

The following layers are applied to a layer support. The data refer to m ² , the data for the silver halide application are converted to silver nitrate.

The abbreviations given in the columns «Sensitivity and« K / A have the meaning given above. In the column "Composition, silver halide and color-imparting couplers, but not other components (e.g. gelatin) are given.

The material is exposed imagewise and subjected to the color negative development process known from the reference “British Journal of Photographic Annual 1979, page 204”.

Comparative example

The comparison material is a highly sensitive (1000 ASA) color negative film on the market, which is exposed and processed in the same way but does not have the layer structure according to the invention.

Virtually the same sensitivities result between the material according to the invention and the comparison material in all spectral ranges. However, the material according to the invention has a significantly reduced granularity:

Claims (4)

1. Photographic recording material having at least one yellow filter layer and at least one blue-sensitive, one green-sensitive and one red-sensitive layer, at least one of which is split into at least three partial layers of different sensitivities, the partial layers being arranged in such a manner that, on imagewise exposure, the light exposes at least one partial layer before passing through the yellow filter layer and exposes at least one partial layer after it has passed through the yellow filter layer, characterised in that - based on at least one layer - the ratio K/A in the most highly sensitive partial layer is greater than that in the next most sensitive partial layer, K being the molar quantity of the colour-producing coupler, calculated as a 4-equivalent coupler, and A being the molar quantity of the light-sensitive silver halide.

2. Photographic recording material according to Claim 1, characterised in that the layers are arranged in such a manner that, on imagewise exposure, the most highly sensitive partial layer is exposed before the light encounters the yellow filter layer and the two least sensitive partial layers are exposed after the light has passed through the yellow filter layer.

3. Photographic recording material according to Claim 1, characterised in that the following layers are arranged on a support in the order given :

at least two red-sensitive partial layers,

at least two green-sensitive partial layers,

a yellow filter layer,

at least one red-sensitive partial layer,

at least one green-sensitive partial layer,

at least one blue-sensitive layer,

and the further removed the partial layers of the same spectral sensitivity are arranged from the layer support, the higher is the sensitivity thereof.

4. Photographic recording material according to Claim 1, characterised in that an additional yellow filter layer is arranged in such a manner that the light passes through this layer before encountering any red-sensitive or green-sensitive partial layer.