EP0173203A2 - Method for preparing colour photographic images - Google Patents

Abstract

Color photographic images are produced by developing a recording material whose silver halide consists of at least 40 mol% of silver chloride, with the developer bath being replenished with so much filler that no overflow occurs.

Description

The present invention relates to a method for producing color photographic images. Fillers are added to the color developer used during development to ensure that the developer properties remain constant.

As is well known, color photographic images are made on a large scale by developing exposed silver halide recording materials. During the development there is a change in the composition in the developer bath: for example the concentration of the color developer substance decreases, while the concentration of the halide increases due to diffusion from the developed material into the bath. If no countermeasures are taken, the developer activity will change. It is from numerous publications, for example from DE-A 2 007 459, 2 007 457, 2 717 674, US-A 3 647 461, US-A 3 647 462, US-A 4 186 007 and EP-A 0 029 722 known to add filler to the developer to counteract such a change. Such fillers are also called "replenisher" in English and "regenerator" in German. By adding the filler, the concentration of the substances consumed during the development process is kept at the desired value. To prevent undesirable accumulation of the halide in the developer at the same time, more filler is added than corresponds to the actual loss of the developer bath. This results in an overflow of developer solution which is relatively rich in halide, while the halide concentration in the replenisher is kept lower. The filler may not contain any halide at all. The overflow is either let into the wastewater or freed of halide, in particular bromide, for example by ion exchange resins or dialysis systems and can be used again after the addition of refreshing chemicals.

In the first case, however, waste water pollution can occur, while in the second case there are additional costs.

These disadvantages have led to the development of so-called low replenishment regeneration solutions (LR regeneration) which contain the necessary substances to such an extent that it has so far been possible to reduce up to half of the previously usual regeneration rate per m ² . The regeneration rate is understood to mean the amount of filler added per m ^{2 of} the developed recording material.

The disadvantage of this quota reduction is that the bromide emerging from the photographic layers accumulates to a correspondingly higher concentration, which is why the developer solution to overcome this inhibition of activity at a higher temperature, e.g. 38 - 40 ° C, must be kept. In addition, the wastewater is still contaminated by the overflow, albeit reduced.

If an attempt is made to further reduce the overflow amount, the solubility limit of the developer substances in alkaline solution is approached. In addition, as the bromide concentration increases, a further increase in temperature is necessary, which increases the influence of atmospheric oxygen and evaporation. It is particularly disturbing that e.g. the commonly used developer substance N-ethyl-N- (ß-methylsulfonamidoethyl) -3-methyl-p-phenylenediaminesesquisulfate monohydrate (= CD 3) is inhibited in its work by the relatively high bromide concentration. Even the increase in solubility made possible by pH values above 12, together with the temperature increase, is not sufficient to achieve the desired development result. An increase in activity can be achieved by adding more active developer substances, which measure entails further complications.

Another problem is the reduction in volume due to evaporation, especially during the idle time of a developing machine. The lack of volume empirical values must be added to the developer solution before starting operation.

The invention had for its object to provide a method for developing color photographic recording materials in which these disadvantages do not occur.

A process has now been found for producing color photographic images in which the development of the exposed silver halide-containing recording material is carried out in a development bath which contains at least one p-phenylenediamine. According to the invention, a recording material is used for this purpose, the silver halide of which consists of at least 40 mol%, in particular at least 70 mol%, of silver chloride; furthermore, only so much filler is added to the developer bath during development that there is no overflow.

The process according to the invention comprises at least one development step in which the exposed silver halide is reduced to silver, a bleaching for the oxidation of the reduced silver and a fixation for removing the silver salts from the recording materials. Bleaching and fixing can be combined in a manner known per se under certain circumstances.

The color development is carried out in an aqueous developer bath. The temperature of the developer solution can be above that for normal regeneration in general usual value remain, also the silver chloride-rich material allows a much shorter development time.

The usual conditions for color development can be observed during development. As a rule, the development takes place at a pH of above 8, preferably above 9.5. The concentration of the color developer substances depends on the circumstances, a concentration of about 4 to 40 mmol / l of the ready-to-use developer solution is particularly preferred.

Development can be carried out in the presence of pH buffers, development inhibitors, anti-fogging agents, water softening complexing agents, preservatives, development accelerators, competitive couplers, fogging agents, auxiliary developer compounds and viscosity modifiers; Reference is made to Research Disclosure 17 544 of December 1978, published by Industrial Opportunities Ltd., Homewell Havant, Hampshire, Great Britain, Section XXI and Ullmanns Encyclopedia of Technical Chemistry, 4th Edition, Volume 18, 1979, in particular pages 451, 452 and 463 to 465. A detailed description of suitable developer compositions and processing methods is given by Grant Haist, Modern Photographic Processing, John Wiley and Sons, 1973, Volumes 1 and 2.

The usual developer substances can be used in the context of the present invention. These preferably contain p-phenylenediamine derivatives as color developer substance, for example: N, N-dimethyl-p-phenylenediamine, 4-amino-3-methyl-N-ethyl-N-methoxyethylaniline, 2-amino-5-diethylamino-toluene , N-butyl-N-α-sulfobutyl-p-phenylenediamine, 2-amino-5- (N-ethyl-N-ß-methanesulfonamidoethylamino) toluene, N-ethyl-NB-hydroxyethyl-p-phenylenediamine, N, N - bis (B-hydroxyethyl) -p-phenylenediamine, 2-amino-5- (N-ethyl-N-β-hydroxyethylamino) toluene. Other useful color developers are described, for example, in J.Amer. Chem. Soc. 73, 3100 (1951). However, black and white developer substances can also be used.

In a particularly preferred embodiment, the developing bath contains the following developer substance A.

According to the invention, the developer bath is supplemented with a filler. The latter is added in such a concentration and amount that there is no overflow, but in such a way that the loss of bath components is compensated for.

In a preferred embodiment, the replenisher does not contain bromide. Here, the proportion of silver bromide in the silver halide emulsions is chosen so that the bromide emerging from the recording material keeps the desired bromide concentration in the developer solution constant.

In a further preferred embodiment, the recording material consists of 100% silver chloride emulsions and the replenisher contains the same bromide concentration as the developer solution.

The regeneration rate depends, among other things, on the composition of the recording material and the components of the replenisher. In a preferred embodiment, a replenisher is used which contains a concentration of 0.02-0.04 mol / l of developer substance A. Under these circumstances, a regeneration rate of approximately 80 to 100 ml / m ^{2 is} particularly advantageous.

It has also been found that the loss of volume due to evaporation can be compensated automatically in a simple manner by using the regeneration rate somewhat less than the carry-over rate and by adding a simple water refill device to the remaining volume deficit.

In one embodiment, the liquid con Assembled partial concentrates individually metered directly into the developer solution, the total volume metered in being to be less than the carried-over volume. The latter is then supplemented by a water refill device.

Following the development, bleaching and fixing can be carried out in a conventional manner, and these steps can also be summarized. The usual bleaching agents can be used. Salts and complexes of trivalent iron and persulfates are particularly suitable. Suitable iron III complexes are e.g. Complexes with aminopolycarboxylic acids, e.g. Ethylenediamine-tetraacetic acid, nitrilotriacetic acid and 1,3-di-amino-2-propanol-tetraacetic acid and hexacyanoferrate. Conventional fixing baths containing a silver halide solvent as the main component can be used for the fixation. Thiosulfates are particularly preferred. The fixing baths can furthermore contain sulfites, borates and other customary additives.

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 oG-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. The color couplers can e.g. are 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 III, 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, Section VII.

In a particularly preferred embodiment, such color couplers are used which couple sufficiently even without the usual addition of benzyl alcohol. Benzyl alcohol is usually used as a phase transfer agent so that the coupling between oxidized color developer and coupler to the image dyes in ge desired degree expires. In practice, however, benzyl alcohol is a constant source of interference, especially due to tar formation. Suitable couplers which can be processed without benzyl alcohol are specified in DE-A 3 209 710, DE-A 2 441 779, DE-A 2 640 601 and EP-A 0 067 689.

Particularly preferred yellow couplers have the following structure:

Particularly preferred purple couplers are:

Particularly preferred cyan couplers are:

Further particularly preferred cyan couplers are phenols which have an alkyl radical with at least 2 carbon atoms in the m position to the phenolic OH group. Particularly preferred couplers of this type are given, for example, in DE-A 33 40 270.

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.

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 consists of at least 90 mol% of AgCl. In principle, the silver halide grains can have a layered grain structure consisting of a core and at least one shell.

In one embodiment, the grains have a layered grain structure from at least two areas of different halide composition - e.g. a core and at least one shell -, wherein at least one region B contains at least 10 mol% of silver bromide, preferably at least 25 mol% of silver bromide, but less than 50% of silver bromide.

The area B can be present both as a core and as a shell around a core. The grains preferably contain a core enveloped by at least one region B. In this case, region B can be present as a shell within the silver halide grain or on the surface of the crystal.

In another embodiment, the grains have at least one zone Z _Br with a high bromide content, the bromide content in the zone Z _{Br being} at least 50 mol% and no bromide-rich zone Z _Br lying on the surface of the silver halide grains.

The silver bromide-rich zone Z _Br can be present as a core or as a layer within the silver halide grain. Preferably 20% by volume of the silver halide of the grain is further from the crystal center than the zone Z _Br rich in silver bromide.

In principle, the silver halide grains can have mixtures of chloride, bromide and iodide. The transition from one zone to an adjacent zone of a different composition can be sharp or continuous.

The silver halide emulsions can be prepared using the customary procedures (for example single entry, double entry, with constant or accelerated material flow). The production according to the double inlet process under control is particularly preferred of the pAg value. Reference is made to the journal Research Disclosure No. 17 643, sections I and II.

The emulsions can be chemically sensitized. 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, also polyamines such as diethylenetriamine or aminomethylsulfinic acid derivatives, e.g. according to Belgian patent 547 323. Precious metals or noble metal compounds such as gold, platinum, palladium, iridium, ruthenium or rhodium are also suitable as chemical sensitizers. This method of chemical sensitization is described in the article by R. Koslowsky, Z.Wiss.Phot. 46, 65-72 (1951). Reference is also made to Research Disclosure No. 17 643, section III.

The emulsions can be optically sensitized in a manner known per se, e.g. with the usual polymethine dyes, such as neutrocyanines, basic or acidic carbocyanines, rhodacyanines, hemicyanines, styryl dyes, oxonols and the like, see F.M. Hamer in "The Cyanine Dyes and related Compounds", (1964), Ullmanns Encyclopedia of Industrial Chemistry, 4th Edition, Volume 18, pages 431 ff and Research Disclosure No. 17643, Section IV, given above.

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. in the article by Birr, Z.Wiss.Phot. 47, (1952), pp. 2-58, and in Research Disclosure No. 17643 above in Section IV.

The components of the photographic material can be incorporated using customary, known methods. Reference is made, for example, to U.S. Patents 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. 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 e.g. DE-OS 2 044 992, US 3 370 952 and US 4 080 211.

The usual layer supports can be used for the materials, for example supports made of cellulose esters, for example cellulose acetate and made of polyesters. Also suitable are paper supports, which can optionally be coated, for example with polyolefins, in particular 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. 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. 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 given above.

example 1 Emulsion preparation, emulsion A

A silver chloride emulsion is produced within 25 minutes by pAg-controlled double entry of a 0.3 N NaCl and a 0.3 N AgNO ₃ solution into a 2.5% gelatin solution brought to a temperature of 55 ° C. The average particle size is 0.15 µm and the emulsion has a monodisperse distribution. The crystals of this starting emulsion are enlarged to 36 times the volume by further addition of 2N NaCl and 2N AgNO ₃ solutions. The pAg value is kept constant at 6.8.

An AgBr / AgCl shell is filled onto the AgCl grains thus produced by simultaneous introduction of KBr / NaCl and AgNO ₃ solutions, the KBr / NaCl solution containing 40 mol% bromide.

The crystals of the emulsion produced in this way have a monodisperse particle size distribution and an average particle diameter of 0.53 μm; the volume fraction of the Br / Cl shell is 10%, based on the total volume of the silver halide crystals. The AgBr content is 4 mol%, based on the total halide.

Recording material

Neben den in der Tabelle angegebenen Substanzen sind die üblichen Bestandteile fotografischer Aufzeichnungsmaterialien, wie Bindemittel und ölformer enthalten.Using Emulsion A, a recording material was produced with the structure shown in the following table:

In addition to the substances listed in the table, the usual components of photographic recording materials such as binders and oil formers are included.

processing

The material was subjected to the following processing:

The developer has the following composition:

Make up to 1 liter with water, pH = 10.2.

The developer was treated with a regeneration rate of 90 ml / m ² with the following make-up solution:

Replenishment solution

Mit Wasser auf 1 Liter auffüllen, pH = 12,3.

Make up to 1 liter with water, pH = 12.3.

The bleach-fix bath has the following composition:

To manufacture the bleach-fixing bath regenerator, the tank filling batch is only made up to 800 ml.

comparison

For comparison, the same recording material is developed in a common development process using common fillers, including overflow:

The developer was regenerated at a rate of 325 ml / m ² using the following replenisher:

Bleach-fix bath as above.

Sensitometric evaluation

The comparison of samples which were developed immediately after the development baths had been prepared and after the throughput of 1,000 m ^{2 of} the recording material showed no sensitometric differences. According to the invention, however, the developer is operated without overflow and without tar formation, while in the comparison test the undesired overflow occurs in an amount of 2400 1 and there is a disturbing formation of tar.

Example 2

The material specified in Example 1 is subjected to the processing process specified in Example 1. The developer specified there is used.

The filling is done by dosing single concentrates and filling with water.

Single concentrates

• Part A, 1 liter
• 700 ml dist. Water,
• 360 g of hydroxylammonium sulfate
• Make up to 1 liter with distilled water. water
• Part B, 1 liter.
• 600 ml dist. Water,
• 216 g of 4-amino-N-ethyl-N- (β-methanesulfonamido) -ethyl-m-toluidine sesquisulfate (monohydrate),
• 40 g sodium sulfite
• 34 g of potassium hydroxide
• With dist. Make up to 1 liter of water, pH = 3.5.
• Part C, 1 liter.
• 800 ml dist. water
• 18 g of diethylenetriaminepentaacetic acid pentasodium salt
• 20 g potassium sulfite,
• 6.3 g potassium bromide,
• 225 g potassium carbonate,
• 117 g of potassium hydroxide
• With dist. Make up to 1 liter of water.

• 1 ml Teil A, 5 ml Teil B, 10 ml Teil C.

The following amounts of parts A - C are added to the developer tank per m ^{2 of} colored paper through a corresponding number of metering pumps:

• 1 ml part A, 5 ml part B, 10 ml part C.

The 74 ml required to completely replenish the volume carried out of the paper is replenished exactly by means of a water refill device.

The same advantageous results as in Example 1 are obtained.

Claims (6)

1. A method for producing color photographic images by developing an exposed silver halide-containing recording material in a developing bath which contains at least one p-phenylenediamine, characterized in that a recording material is used for this purpose, the silver halide of which consists of at least 40 mol% of silver chloride and that Only enough filler is added to the developer bath during development that there is no overflow. 2. The method according to claim 1, characterized in that the silver halide in the recording material consists of at least 70 mol% of silver chloride. 3. The method according to claim 1, characterized in that the silver halide consists of at least 90 mol% of AgCl. 4. The method according to claim 1, characterized in that the developing bath contains no benzyl alcohol. 5. The method according to claim 4, characterized in that the following p-phenylenediamine is contained in the bath:

6. The method according to claim 5, characterized in that the replenishment is carried out by metering concentrates, combined with a water refill to keep the bath level constant.