CH616009A5 - Colour-photographic material - Google Patents

Description

The invention relates to a color photographic material with a plurality of silver halide emulsion layers sensitized to different sub-regions of the visible spectrum, which contains non-diffusing compounds to influence the sensitometric properties of at least one silver halide emulsion layer, which, as a result of a reaction with color developer oxidation products, diffuse substances which inhibit the development of the silver halide in freedom able to bet.

A number of measures are known for influencing the sensitometric properties, in particular the shape of the gradation curves of the individual silver halide emulsion layers. Different emulsions can thus be mixed with one another, which differ in terms of one or more parameters such as chemical composition, structure and crystal shape of the silver halide grains, average grain size and grain size distribution. In order to achieve a specific form of the gradation curve with this measure, it must be possible to choose from a large number of basic emulsions, which requires an appropriate stockpiling. Another means consists in the setting of a certain quantity ratio between silver and color coupler, which is however limited, for example, by the fact that a certain grain size may not be exceeded.

Of course, it is also possible to influence the shape of the gradation curve by the type of development. However, this is forbidden in practice, in which standardized development programs are introduced, which must not be changed.

It is also known to change the shape of the gradation curves by using compounds from which diffusing substances are released during color development, which are capable of inhibiting the development of the silver halide. Such compounds have become known under the name DIR couplers (DIR = Development Inhibitor Releasing) and have been described, for example, in GB-PS 953 454. These are usually color couplers that have a substituent in the coupling site that is split off during the coupling to form a diffusing compound that inhibits the development of the silver halide. Since the development of an exposed material releases the inhibitors in a particularly large amount in the parts of the image in which the development is most advanced, this also results in a particularly strong inhibition, which overall results in a flattening of the gradation curve, i.e. H. expressed in a decrease in gradation. Further advantageous results when using DIR couplers can be seen in a refinement of the color grain and in a targeted influencing of the interimage effect.

Principally similar effects are also achieved with the so-called DIR connections, which are described, for example, in US Pat. No. 3,632,345. In contrast to the DIR couplers mentioned above, these are not color couplers. Since these compounds do not produce a permanent dye and accordingly do not contribute to the construction of the color image, they can be used in a particularly wide variety of ways. H. different DIR connections are not required for the individual partial color layers. The DIR connections of DE-OS 2 359 295 are based on the same principle. Unless otherwise noted, both the aforementioned DIR connections in the narrower sense and the aforementioned DIR couplers are referred to below as DIR connections understood, d. H. in general, all compounds which, when reacted with color developer oxidation products, release diffusing, organic substances which inhibit the development of the silver halide.

If the gradation form of a silver halide emulsion is to be influenced in a very specific way by using such a DIR compound, a large assortment of DIR compounds is required in order to be able to select such a DIR compound which can be achieved with regard to its reactivity this line is particularly suitable.

The invention is based on the object, starting from a given silver halide emulsion, to influence the sensitometric properties, in particular the shape of the gradation curve, in a targeted manner without the development conditions or the layer parameters, such as the coupler-silver ratio or - in the case of mixed emulsions - the Basic emulsions or their mixing ratio must be changed and in particular without the need to keep a large range of DIR compounds in stock.

The object is achieved according to the invention in that a combination of at least two DIR compounds or at least two dispersion forms of the same DIR compound is used, which differ in a certain way with regard to their reactivity.

It has been shown that the shape of the gradation curve can be influenced in different ways by DIR compounds of different reactivity. This becomes particularly clear when the gradation curve of the respective silver halide emulsion layer is divided for assessment

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into a first gradation section and a second gradation section, and if the respective determined gradation values (yi, J2) are specified separately for the two sections. Depending on the selected silver halide emulsion, these two gradation values can agree or can also differ considerably from one another, where yi can be larger or smaller than yi. When using a high reactivity DIR compound, yz can be much larger than yi, d. H. the first gradation section would be relatively flat, and the second gradation section would be relatively steep, in other words, the gradation curve would have a more or less strong sag. When using a DIR compound of lower reactivity in the same emulsion, on the other hand, y2 can only be slightly larger or also equal or smaller than the corresponding yi value; the sag would be reduced or would even bump up; the gradation curve would then have a flatter and elongated course overall. When comparing silver halide emulsion layers to which DIR compounds of different reactivity are added in varying amounts, the layer with the more reactive DIR compound shows the higher y2 value at the same 20 yi value. Conversely, with a comparable y2 value, the layer with the less reactive DIR compound shows the higher yi value. Of course, transitional forms of the gradation curve can also be set, although this would require a large range of DIR compounds with graded reactivity.

The material according to the invention contains at least two DIR compounds of different reactivity. This also makes it possible to set gradation curves that lie between those that can be reached with the individual DIR connections. In contrast to the aforementioned method, in principle only two DIR compounds of different reactivity are required for this, by mixing them in a suitable ratio, which can be determined by simple routine tests, the desired gradation form is set. The advantage of the teaching according to the invention is therefore that with a very limited number of DIR compounds, in fact, even with only two DIR compounds of different reactivity, the same variety of gradation forms can be set as when using a single DIR compound which has to be selected from a large number of available DIR compounds with graded reactivity. According to the invention, a mixture with “average reactivity” is produced, so to speak, by mixing the DIR compounds with different reactivities, which can be compared with an individually used DIR compound with a corresponding reactivity. However, the combination has a certain peculiarity compared to the individually used DIR compound, 00 which results from a consideration of the respective reaction constant k. With an individually used DIR compound, provided that the range of developer oxidation products is approximately constant, the amount of development inhibitor produced in the unit time is primarily proportional to the concentration of DIR compound and the reactivity constant k of the DIR compound . The DIR compound is present only in a limited amount, especially in the case of high reactivity, which decreases continuously as the reaction proceeds; consequently, the production of development inhibitor also slows down, and more so the greater the reactivity constant k is, in other words the more reactive the DIR compound is. A combination of two DIR compounds with different reactivities results in an “average reactivity constant” depending on the quantitative mixing ratio of the DIR compounds. However, this is no longer a constant, but strictly speaking only applies to the beginning of the reaction. The further the reaction progresses, the more the mixing ratio shifts in favor of the less reactive DIR compound, since the more reactive DIR compound is consumed more quickly due to its greater reactivity. This also changes the "mean reactivity constant" and asymptotically approaches the reactivity constant k of the less reactive DIR compound, and the faster the greater the difference in the reactivities of the individual DIR compounds of a combination. It is merely an attempt to interpret the effects achieved with the material according to the invention without at the same time claiming scientific completeness. This is in no way intended to limit the invention in any way.

In principle, suitable as DIR compounds are all compounds which can be embedded in the layers of a photographic material in a diffusion-resistant manner and which, as a result of a reaction with color developer oxidation products, release a diffusing, organic substance which is capable of inhibiting the development of the silver halide. These DIR compounds include both the DIR couplers mentioned at the outset, which, for. B. are described in GB-PS 953 454, as well as the DIR compounds of US Pat. No. 3,632,345 and DE-OS 2,359,295. Further DIR compounds suitable for the material according to the invention are the subject of DE-OS 2 448 063 and 2 502 892. The development inhibitors which are split off can be, for example, heterocyclic compounds such as benzotriazole; however, they are preferably those which have an inhibiting mercapto group. Accordingly, thioether compounds are preferably used as DIR compounds which contain a thioether substituent at a reactive point in the molecule and which split off as a diffusing mercapto compound as a result of a reaction with color developer oxidation products. This reaction is generally a type of substitution reaction, the split-off inhibitor residue being substituted by the rest of the color developer oxidation product.

It is desirable that the DIR compounds themselves not be able to diffuse in the layers of a photographic material. For this reason, they are equipped with residues which make them resistant to diffusion or are so insoluble in the embedded form that there is no diffusion during the production of the layer structure or during development.

Those residues which make it possible to store the compounds described in the hydrophilic colloids customarily used in photographic materials in a diffusion-resistant manner are to be regarded as diffusion-fixing residues. Organic radicals which generally contain straight-chain or branched aliphatic groups and optionally also isocyclic or heterocyclic aromatic groups are preferably suitable for this purpose. The aliphatic part of these residues generally contains 8-20 carbon atoms. With the rest of the molecule, these residues are either directly or indirectly, e.g. B. connected via one of the following groups: -NHCO-, -NHSO2-, -NR-, where R is hydrogen or alkyl, -O- or -S-. In addition, the diffusion-proofing residue may also contain water-solubilizing groups, such as. B. sulfo groups or carboxyl groups, which may also be in anionic form.

The two DIR compounds contained in the material according to the invention must differ in their reactivity by more than a factor of 1.5. A measure of the reactivity is the reaction rate constant k. However, this need not be given as an absolute value, since it is only a question of the relation of the k values of the two DIR connections. It is therefore sufficient to determine relative k values, the k value of any coupler or any DIR connection being chosen arbitrarily as a reference value

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can be. It is therefore possible to use any method to determine the k-values with which relative rate constants can be determined. Such a method is described, for example, by J. Eggers in “Messages from the Agfa Research Laboratories”, Leverkusen-Munich, Volume III, page 81 ff, 1961. This method is primarily designed to determine the relative coupling speeds of color couplers. However, the relative reaction rate constants of colorless coupling substances can also be determined if a color coupler is used as the standard or reference substance. The decrease in the absorbance of the dye produced from the color coupler is a measure of the reaction rate of the colorless coupling substance to be measured, which competes with the color coupler for the existing color developer oxidation product.

The shape of the gradation curve most influenced in the material according to the invention is largely determined by

that the two DIR connections compete to a certain extent. It will therefore essentially depend on the particular form of dispersion of the DIR compound used. It has been shown that the relative reaction rate constants of a DIR compound determined according to one of the known methods can assume different values, depending on how the DIR compound is dispersed. It is conceivable that the same DIR compound can be used both as an aqueous alkaline solution and in the form of an emulsifier using a so-called coupler solvent or oil-forming agent. Hydrophobic DIR compounds can be used in the form of aqueous dispersions, which can optionally be prepared using low-boiling organic solvents, or in the form of the aforementioned emulsions. In the case of emulsions, the k value can also depend on the type and amount of solvent (oil former), as well as on the type of wetting agent and the size of the droplets. For this reason, it is desirable to use the effective reaction rate constant (keff) of the DIR compound in its respective dispersion form as a decision criterion for the usability of the DIR compound in the sense of the present invention. It is therefore expedient to use the DIR compound in the same dispersion form in which it should also be used in the color photographic material for determining the relative reaction rate. In the material according to the invention, the kefr values of the DI R compounds to be combined must differ by more than a factor of 1.5. It is difficult to state an upper limit for this factor. In principle, the diversity of all adjustable gradation forms is greater the more the two DIR compounds differ in their reactivity, i. H. the larger this factor is. On the other hand, the less reactive DIR compound must not be so inert that it does not participate to any appreciable extent in the reaction during the relatively short development period of the order of 1 to 15 minutes. In practice, therefore, the ketr values will rarely differ by more than a factor of 100; however, the range from 2 to 20 is preferred.

Influencing the core values by the particular dispersion form of the DIR compound naturally also opens up the possibility of using only a single DIR compound in the material according to the invention, but in two different dispersion forms, provided that their core values differ and are assumed to be more than a factor of 1.5 that the dispersion forms are stable enough and are retained in the finished layer.

The mixing ratio of the DIR compounds to be combined can be varied within wide limits. The optimal mixing ratio to achieve a certain gradation shape is determined by simple routine tests. As a rule, the combination contains one DIR compound in 1 to 20 times the amount of the other, DIR compound.

If a color coupler is present, it should expediently have a reactivity of the same order of magnitude as the DIR compounds. Preferably, the more reactive DIR compound has a slightly greater reactivity than the color coupler and the less reactive one has a lower one.

The invention is suitable in principle for any silver halide emulsion for setting the shape of the gradation curve regardless of whether a color coupler or an other color-imparting compound is present.

However, the invention finds particularly preferred application in color photographic materials, in particular in those which contain color couplers and which are chromogenically developed. However, it is also conceivable to use the invention for the 2D color diffusion method, since there may also be interest in modifying the gradation curve of the silver halide emulsion layers.

The customary silver halide emulsions are suitable for the present invention. These can contain up to 20 mol% as silver halide, 2-, silver chloride, silver bromide or mixtures thereof, optionally with a low silver iodide content. It can be any type of silver halide emulsions, e.g. B. homodisperse or heterodisperse emulsions, furthermore those whose grains have such a homogeneous or structured structure. For example, conversion emulsions, e.g. H. Emulsions, the silver compounds of which are first precipitated as more water-soluble silver salts and then partially or completely converted into less soluble silver halides, such as, for. B. »described in US Pat. No. 2,592,250, is suitable in the same way as emulsions whose silver halide grains consist, for example, of the core and shell of different chemical compositions or different degrees of sensitization. It can be usual negative working emulsions as well as veiled or unveiled direct positive emulsions.

Gelatin is preferably used as the binder for the photographic layers. However, this can be replaced in whole or in part by other natural or synthetic bin-4 agents. On natural binders such. B. alginic acid and its derivatives such as salts, esters or amides, cellulose derivatives such as carboxymethyl cellulose, alkyl cellulose such as hydroxyethyl cellulose, starch or their derivatives such as ether or ester or caragenates are suitable. Of synthetic vi binders mention should be made of polyvinyl alcohol, partially saponified polyvinyl acetate, polyvinyl pyrrolidone and the like.

The emulsions can also be chemically sensitized, e.g. B. by adding sulfur-containing compounds during chemical ripening, for example allyl isothiocyanate, allyl- »thiourea, sodium thiosulfate and the like. Reducing agents, e.g. B. the tin compounds described in Belgian patents 493 464 or 568 687, also polyamines such as di-ethylenetriamine, or aminomethanesulfinic acid derivatives, e.g. B. m can be used according to Belgian patent 547 323.

Precious metals such as gold, platinum, palladium, iridium, ruthenium or rhodium and compounds of these metals are also suitable as chemical sensitizers. This method of chemical sensitization is described in the article by R. Koslow-sky, 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

Molecular weight between 1000 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. The condensation products have a molecular weight of at least 700, preferably more than 1000. 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.

The emulsions can also be spectrally sensitized, e.g. B. by the usual mono- or polymethine dyes, such as acidic or basic cyanines, hemicyanines, streptocyanines, merocyanines, oxonols, hemioxonols, styryl dyes or other, also trinuclear or polynuclear methine dyes, for example rhodacyanines or neocyanines. Such sensitizers are described, for example, in the work of F. M. Hamer "The Cyanine Dyes and Related Compounds" (1964), Interscience Publishers John Wiley and Sons.

The emulsions can contain the usual stabilizers, such as. B. homopolar or salt-like compounds of mercury with aromatic or heterocyclic rings, such as mercaptotriazoles, simple mercury salts, sulfonium-mercury double salts and other mercury compounds. Suitable stabilizers are also suitable azaindenes, preferably tetra- or penta-azaindenes, in particular those which are substituted by hydroxyl or amino groups. Such connections are described in the article by Birr, Z. Wiss. Phot. 47, 2-58 (1952). Other suitable stabilizers are u. a. heterocyclic mercapto compounds, e.g. B. phenylmercapto-tetrazole, quaternary benzothiazole derivatives, benzotriazole and the like.

The emulsions can be hardened in the customary manner, for example with formaldehyde or halogen-substituted aldehydes which contain a carboxyl group, such as mucobromic acid, diketones, methanesulfonic acid esters, dialdehydes, carbodiimides, carbamoylpyridinium salts (e.g. DE-OS 2 245 635) and carbamoyl oxychloride (e.g. DE-OS 2 408 814).

As already mentioned, the invention is suitable for color photographic materials and here primarily for those which are developed by the chromogenic development process and which contain color couplers which do not diffuse to produce the various image dyes. Such materials generally contain at least three light-sensitive silver halide emulsion layers on a transparent or opaque layer support, each of which is particularly sensitive to light from a different third of the visible spectrum. One of the layers has an increased sensitivity to blue, green or red light. A non-diffusing color coupler is assigned to each of these layers. Furthermore, each of these layers in the material according to the invention is assigned a combination of a more reactive and a less reactive DIR compound.

“Assignment” and “assigned” is understood to mean that the mutual arrangement of silver halide emulsion and DIR compound or of silver halide emulsion and color coupler is of such a kind that an interaction between them is possible, which is an image-like correspondence between the formed silver image and the formed dye image and pictorial distribution of the released developmental. hibitors allows. To achieve this assignment, the DIR compounds and also the color coupler can be embedded in the silver halide emulsion layer itself or in a binder layer adjacent to it. Color couplers and DIR connections do not necessarily have to be in the same layer.

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The non-diffusing color couplers as well as the non-diffusing compounds which release a development inhibitor can be added to the light-sensitive silver halide emulsions or to the casting solutions for the non-light-sensitive neighboring binder layers by customary known methods. If the compounds are water-soluble or alkali-soluble, they can be added to the emulsions in the form of aqueous solutions, if appropriate with the addition of water-miscible organic solvent solvents, such as ethanol, acetone or dimethylformamide. To the extent that the non-diffusing color couplers and the non-diffusing development inhibitor-releasing compounds are water- or alkali-insoluble compounds, aqueous dispersions of i5 can be prepared by, for example, aqueous slurries of the respective compound by intensive stirring, optionally with the addition of gelatin or another binder. The compounds can also be emulsified in a known manner, e.g. B. by mixing a solution of these compounds in a low-boiling organic solvent directly with the silver halide emulsion or first with an aqueous gelatin solution, whereupon the organic solvent is allowed to evaporate. A gelatin emulsate of the respective compound obtained in this way can then be mixed with the silver halide emulsion. Optionally, so-called coupler solvents or oil formers are also used to emulsify such hydrophobic compounds, which are generally higher-boiling organic compounds which include the non-diffusing color couplers to be emulsified in the silver halide emulsions and the compounds which split off the development inhibitor in the form of oily droplets. In this connection, reference is made, for example, to US Pat. Nos. 2,322,027.3 689 271.3 764 336 and 35 3 765 897. If the DIR compounds of a combination are both used in the form of an emulsifier, they can be in the form of a common emulsate or can also be used in the form of separate Emulgate.

In principle, all couplable, 40 organic compounds are suitable as color couplers insofar as they can undergo an oxidative condensation reaction (coupling) with the formation of a dye with color developer compounds, predominantly with p-phenylenediamine derivatives. Typically derivatives of phenol or naph-45 thol as cyan couplers, derivatives of pyrazolone or indazolone as magenta couplers and open-chain ketomethylene compounds, e.g. B. derivatives of benzoylacetanilide or pivaloylacetanilide used. Both 4-equivalent couplers and 2-equivalent couplers are suitable. The latter, as is well known, requires only two equivalents of silver halide to form the dye. They contain a substituent in the coupling point, which is split off during the color coupling. If this removable substituent contains a dye residue or forms a dye together with the coupler molecule residue, 55 it is a colored coupler that could be used as a so-called mask coupler to compensate for undesired secondary densities of the image dyes. Reference is made to the overview articles by W. Pelz "Farbkuppler" in communications from the research laboratories of Agfa, Leverkusen-60 Munich, volume III, page 111, Springer Verlag (1961) and K. Venkataraman "The Chemistry of Synthetic Dyes", volume IV , Pp. 341-387, Academic Press (1971).

If one or more silver halide emulsion layers of the material according to the invention is formed as a double layer, 65 consisting of two partial layers, which may have different sensitivity or different silver coupler ratio, which is to achieve a better sensitivity-granularity ratio, i. H.

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To increase sensitivity while avoiding coarsening of the grain of color has been proposed variously (e.g. DE-PS 1 121 470, US-PS 3 726 681, DE-OS 2 322 165, 2416 982), one or each of these sub-layers of a double layer in the Material according to the invention contain a combination of different reactive DIR compounds. However, it is also considered to be an embodiment of the invention if the two DIR connections of a combination are in different sub-layers of a double layer, i. H. if, for example, the more sensitive silver halide partial layer contains the more reactive and the less sensitive silver halide partial layer contains the reactive DIR compound or vice versa.

As already stated, the invention offers the possibility of modifying the shape of the gradation curve of a silver halide emulsion layer in the desired manner without changing the emulsion with regard to its composition and, if appropriate, its silver coupler ratio. This opens up a further welcome aid to the person skilled in the art for adjusting the gradation of a single layer and thus for improving the color rendering as a whole. As is known, the partial color gradations generated in the known silver halide emulsion layers should coincide as far as possible in order to enable a balanced color reproduction overall.

Another advantage of the invention is seen in the improved possibility of influencing the interimage effects (IIE), i. H. effects in a particular silver halide emulsion layer, the cause of which is to be found in the development process of another silver halide emulsion layer. This is to be understood in such a way that the inhibitor substances released in the development of the DIR compound in a silver halide emulsion layer are not only able to inhibit development in the same layer, but due to their diffusibility also reach other silver halide emulsion layers of the same material and can also take effect there. By consistently utilizing and cultivating the interimage effects, the color can be reproduced, in particular the color brilliance can be further improved.

Finally, another advantage of the invention is that the y-development time behavior of the photographic material can also be set in a simple manner. The y development time behavior means the dependence of the y values achieved during development on the respective development time. With a flatter y development time behavior, the material is less sensitive to fluctuations in the development time. On the other hand, a steeper y-development time behavior may be desired in special cases, namely if the setting of a specific y-value is to be influenced in a simple manner by varying the development time. Less reactive DIR compounds show a flatter y development time behavior than more reactive ones. By mixing a 5 more reactive and a less reactive DIR compound in a suitable quantitative ratio, a y-development time behavior can be set in a simple manner, which lies between those that can be achieved with the individually used DIR connections.

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Examples

(The percentages of concentration are by weight.) The DIR compounds, individually or in the combination according to the invention, are preferably used in multi-layer structures such as those described in US Pat. B. are customary for the production of photosensitive negative or positive working photographic color materials.

The effectiveness of the combination of DIR compounds according to the invention is demonstrated using the example of a layer structure typical of Colornega-20 tiv materials or on partial layers thereof:

Photosensitive photographic material:

Layer structure 25 underlay: Substrated cellulose triacetate underlay.

a) intermediate view of gelatin (1 | i);

b) blue-green layer, consisting of an emulsion which is sensitized to the red spectral range, and a color coupler for blue-green (silver application: 5 g Ag / m2);

30 c) intermediate layer of gelatin (1 | i);

d) purple layer consisting of an emulsion which is sensitized to the green spectral range and a color coupler for purple (silver application: 4.5 g Ag / m2);

e) intermediate layer of gelatin (1 ji);

ì j f) yellow filter layer (2 u.);

g) yellow layer consisting of an emulsion which is sensitized to the blue spectral range and a color coupler for yellow (silver application: 1.5 g Ag / m2);

h) protective layer of gelatin (1 ii).

40 The material is in the usual way, for. B. cured with trisacryloylhe-xahydrotriazine. The individual red- (b), green- (d) and blue- (g) sensitive sub-layers are produced by pouring the following casting solutions:

b) 1 kg of a red-sensitized silver halide emulsion (100 g Ag / kg emulsion) whose silver halide consists of 98 mol% of silver bromide and 2 mol% of silver iodide, 50 ml of a 1% solution of 1, 3,3a, 7-tetraza-4-hydroxyl-6-methylidene in methanol, 240 g of a coupler dispersion of 15 g of the cyan coupler of the formula:

-co-nh- (ch2) 4-o- o

~ 0C12H25

in 7.5 g of phthalic acid dibutyl ester and 30 g of diethyl carbonate, 100 ml of a 4% aqueous gelatin solution, 0.8 g of "Merso-lat" R (wetting agent, sulfated paraffin hydrocarbons) optionally one or two dispersions of DIR compounds 6 "in varied amounts; the preparation of the dispersion is described below; 10 ml of a 10% aqueous saponin solution, 1000 ml of water.

CO-CH

d) The composition of the casting solution for the green-sensitive layer corresponds to that of the red-sensitive layer b with the exception that the emulsion is sensitized to the green region of the spectrum and instead of the cyan coupler dispersion 150 g of a dispersion of 15 g of the magenta coupler of the formula

Cl - //

NH-CO

X0C1AH "N = C-NH- {'io 33

/

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and 1.7 g of the DIR compound of the formula ch3- (ch2) 15-nh-so2

-tcVtJ0

in a composition analogous to the coupler emulsifier in layer b.

g) The composition of the casting solution for the blue-sensitive layer corresponds to that of the red-sensitive layer b, with the exception that the emulsion is only sensitized to the blue region of the spectrum and, instead of the cyan coupler dispersion, 175 g of a 5% solution of the yellow coupler of the formula

SCUH

{_} - co-ch2-co-nh- ^)

NH-C0-C1qH37 0CH3

in an aqueous 8% gelatin solution; however, the blue sensitive layer contains no DIR compound. 30th

The gelatin layers a, c, e and h are produced by pouring the following casting solution:

125 ml of a 10% gelatin solution, 500 ml of water

5 ml of a 10% solution of saponin The casting solution for the filter yellow layer f is, with the exception of the addition of 1.4 g of finely dispersed metallic silver, as is generally customary as a blocking filter for the blue spectral component of the light, with the casting solution for the gelatin layers a , c, e and h identical.

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Preparation of the dispersion of the DIR compounds for the red-sensitive layer b.

A solution of 6 g of DIR compound in 12 ml of ethyl acetate and 3 g of tricresyl phosphate is, with vigorous stirring, using a mixed siren in a solution of 100 ml of a 4% aqueous gelatin solution and 0.8 g of «Mersolat» R (wetting agent; sulfonated paraffin hydrocarbons) emulsified. After the emulsification, the ethyl acetate is evaporated off in vacuo.

For the example, two DI R couplers are used with different reactivities:

A blue-green coupling DIR coupler 1 of the formula

B blue-green coupling DIR coupler 2 of the formula

The relative coupling rate constants of these two DIR coupler dispergate behave like keff,: keff2 = 1:10 in the developer system used.

These relative reactivities of the two DIR coupler dispergate were determined using the competitive coupling method described by J. Eggers in “Messages from the Agfa Research Laboratories”, Leverkusen-Munich, Vol. III, pp. 81 ff, Springer Publishing house (1961).

The layer structure consists of layers a to h, as indicated above. The behavior of the DIR compounds in the red-sensitive layer b is examined. In those examples, the two DIR couplers are mixed in the form of separate emulsions in the desired proportions. The same results are obtained, however, if the two DIR couplers are used in the form of a common emulsate.

processing

It is exposed in a conventional sensitometer behind a gray wedge and behind each color separation filter blue, green and red, or with white light, and the exposed material in a color developer of the following composition.

wraps:

2g

Sodium salt of isopropanol diamine tetraacetic acid

30 g

Potash

4g

Potassium sulfite

1.5 g

KBr

2g

Hydroxylamine

5g of the color developer of the following formula nh2

r ^ _CH3. H2S04. H20

Top up c2h5-n-c2h ^ oh to 1 liter. Set pH to 10.3. Development: for 5 minutes at 25 ° C.

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The further processing stages specified below each last 8 minutes. The bath temperatures are also 25 ° C.

Stop bath:

30 ml acetic acid (concentrated)

20 g of sodium acetate water per 1 liter

Irrigation bleach bath:

100 g potassium ferricyanide 15 g potassium bromide water per 1 liter

Watering

Fixing bath: 20% aqueous solution of sodium thiosulfate final rinsing.

The blue green densities were measured as usual in a densitometer behind the red filter. To characterize the gradation curve, it was broken down into two sections as follows and the gamma (y) for each section was determined as the increase in the secant.

Section 1 (yi): Part of the gradation curve from the sensitivity point (D = 0.2 via fog) to an exposure value higher by 0.8 log I.t units.

Section 2 (y2): Part of the gradation curve from the end point of Section 1 to an exposure value that is a further 0.8 log I.t units.

Since these experimental setups are not masked, the secondary densities of the dyes in the other layers interfere with the determination of the actual interimage effect. In order to eliminate this disturbing influence of the secondary densities, the analytical densities are determined in a known manner from the measured densities by conversion and the corresponding analytical gradation curves are created. Only these then serve to determine the y or IIE values.

The yi and y2 values determined in this way are shown in the following table in the «Gradation form» column.

Table 1

Sample DIR-K. 1

DIR-K 2

Gradation form lIEbg at g / kg emuls.

g / kg emuls.

Y>

y2

y>

Y2

1

1.44

0.85

1.41

48

68

2 2.4

1.15

1.39

40

45

3 7.3

0.81

1.00

18th

25th

4 2.8

0.28

0.99

1.40

38

40

5 3.6

0.36

0.82

1.30

37

32

6 4.75

0.47

0.79

1.15

26

29

7 2.4

0.36

0.89

1.38

-

-

8 4.75

0.24

0.96

1.18

-

-

Samples 1 and 3 show that with 1.44 g of the more reactive DIR coupler and 7.3 g of the less reactive DIR coupler the yi practically matches, while the yi is significantly higher with the DIR-K 2. Samples 1 and 2 show that with the DIR coupler quantities 1.44 g of the DIR-K 2 and 2.4 g of the DIR-K 1, the yi in the DIR-K 2 is significantly higher at approximately the same yi. The quantitative ratios of the DIR couplers for the mixtures of samples 4, 5 and 6 were chosen in the weight ratio DIR-K 1: DIR-K 2 as 10: 1, that is to say in reverse proportion to their relative rate constants for the coupling reaction (keff). It is to be expected that the same amount of inhibitor will be released at the beginning of the development from both DIR couplers and that towards the end of the development more inhibitor will result from the less reactive DIR-K 1 than from the more reactive DIR-K 2, since the Concentration of the latter decreases faster due to its faster coupling kinetics and the small amount used. Samples 4, 5 and 6 show that, with the amounts of DIR coupler combination selected here, gradation forms are achieved which lie between those of samples 1, 2 and 3 and cannot be achieved with the individually used DIR couplers. Of course, the quantity ratio of the DIR couplers can also be varied, which in turn leads to other gradation forms, such as samples 7 (DIR-K 2: DIR-K 1 = 1: 6.6) and 8 (DIR-K 2: DIR- K 1 = 1:20) show.

However, the use of DIR compound mixtures is of interest not only because of the gradation forms that can be achieved, but also because of the different interimage effects (IIE) that can be achieved indirectly in one's own and in particular in the adjacent sub-image layers of the overall layer association. The interimage effects of the blue-green layer shown in the table in the column “IIE” show which different values can be achieved.

The IIE is defined here in the following way:

IIE = Ts - Sfw • 100

0.6

s = selective exposure (red in the present case) w = white exposure

Another advantage of combining several DIR couplers in a partial image layer is that a different y development time behavior can thereby be set.

Less reactive DIR couplers show a flatter y development time behavior than more reactive ones. Mixtures of a more reactive and a less reactive DIR coupler make it possible to set a y development time behavior that lies between the extreme values that can be achieved with the individual DIR couplers. This fact becomes clear from the diagram in the drawing, in which the development time in minutes is plotted as the abscissa and the y2 value obtained in each case is plotted as the ordinate. The curves labeled 1, 2 and 4 show the behavior of the samples from Table 1 labeled in the same way.

8th

5

10th

15

20th

25th

30th

Ì i

4n

45

50

55

(i

! HUitl drawings

Claims (5)

616009 1. Photosensitive color photographic multilayer material which, in association with at least one silver halide emulsion layer, contains a non-diffusing DIR compound which, as a result of a coupling reaction with color developer oxidation products, is able to release a diffusing mercapto compound compound which inhibits the development of the silver halide, characterized in that at least one silver halide emulsion layer is associated with a combination of at least a first and a second such DIR compound or a combination of at least a first and a second dispersion form of the same DIR compound, the first and the second DIR compound or the same DIR compound in the first and the second dispersion in their reactivity (keff) differ by more than a factor of 1.5. 2. Material according to claim 1, characterized in that the first DIR compound or the DIR compound in the first dispersion form in 1 to 20 times the molar amount, based on the second DIR compound or the second dispersion form of the DIR compound, is present in the silver halide emulsion layer or a non-light-sensitive binder layer adjacent to it. 2nd PATENT CLAIMS 3. Material according to claim 1, characterized in that it contains at least one thioether compound acting as a DIR compound. 4. Material according to claim 1, characterized in that a non-diffusing color coupler is assigned to the silver halide emulsion layer. 5. Material according to claim 1, characterized in that the first and the second DIR compound or the same DIR compound in the first and the second dispersion form in different, for the same spectral range sensitized sub-layers of a light-sensitive silver halide emulsion double layer.