DE4105918A1 - PHOTOGRAPHIC PROCESSING METHOD - Google Patents

Description

For processing photographic films and papers are successively various chemical treatment solutions needed: developers, bleaching baths, Fixing baths, reverse baths, stabilizing baths.

In order to keep the activity of these treatment solutions constant in continuous operation, these treatment solutions are regenerated. Here are per square meter Photographic material used between 100 and 2000 ml regenerator solution - as applicable which photo process is applied.

The resulting in the regeneration bath spills are not discarded, but collected, purified, chemically activated and re-treated for treatment Photo materials used (recycling process).

One problem remains unresolved in this recycling:
The chemicals absorbed by the photographic material, as well as the superficially attached chemicals, are irretrievably transported to the following treatment baths and finally into the water, thus entering the wastewater.

The object of the invention is to recover these amounts of chemicals and feed again into the procedure.

The solution to this problem is achieved by the processing described below processing methods.  

Regardless of the commonly used recycling process, with which z. Z. the bath overflows are processed, includes the inventive Method the almost quantitative feedback of the photo material in the Irrigation entrapped chemicals in the treatment fluid from which they were were initially deported.

For example, a photographic treatment bath contains chemicals in one Concentration of 100 g per liter, z. B. a bleach the bleach Iron ammonium salt of ethylenediaminetetraacetic acid.

From this bath, 50 to 70 ml of solution are transferred to the subsequent washing per square meter of photographic material. The mean value is 60 ml / m ² .

If the washing rate - as prescribed - is approx. 2 l / m ² , you will get no washing water, loaded with a chemical concentration of approx. 3 g / l. If a second, identical washing step follows this washing, the chemical concentration is reduced to approx. 0.1 g / l.

If, however, the washing rate z. B. reduce to only 140 ml / m ³ , so would result in the first washing step, a chemical concentration of about 30 g / l (6 g in 200 ml). Accordingly, a 6-step wash would be required to reach a chemical level of about 0.1 g / L in the last wash tank. That would be technically very complicated.

The invention is now a method for wet processing of a be lightened photographic recording material in continuous operation with at least a treatment solution containing at least one photographic processing scheme contains, whose working solution regenerated and their overflow in the usual way rejuvenated and reused, and immediately followed by watering of the recording material, characterized in that after the washing resulting, with the processing chemical from the previous treatment  loaded wash water to a concentration of the processing chemical, the at least equal to the treatment solution, concentrated and either the Treatment solution or the corresponding regenerator is added.

The watering can be carried out in one stage, but is preferably more stage, in particular carried out in countercurrent cascade.

The chemical concentration of the wash water can be removed by evaporation excess water, increased by ultrafiltration or by reverse osmosis become.

Suitable treatment solutions are the following baths:

• a) color developer bath,
• b) black and white developer bath,
• c) bleaching bath,
• d) fixer,
• e) reverse bath,
• f) bleach-fix bath,
• g) Stabilizer.

In a preferred embodiment, each treatment step is followed by one Inventive washing step.

The amount of water in the washing or washing step is preferably from 40 to 600 ml / m ^{2 of} treated material, in particular from 100 to 300 ml / m ² .

The concentration preferably takes place with a factor of 2 to 8. It is essential that at least the concentration of processing chemical is reached, as it prevails in the processing bath. It can also be up to the  Concentration concentrated, as it prevails in the regenerator, however, preferably only up to the concentration of the processing bath concentrated.

Optionally, the loaded with chemicals wash water before the return into the processing or regeneration solution of a cleaning operation for example, with the aid of an ion exchanger, to the constituents Separate, not from the processing solution but from the processed Material come, provided that their enrichment as unfavorable for the process would result. This purification may preferably after the concentration to together with the bath overflow.

In a preferred embodiment of the method, the inventive Watering in a countercurrent washing device from at least one Wäs sizing tank with one inlet for the wash water and one drain for with Chemical enriched wash water as well as powered rollers for the Transporting the photographic material through the tank on a U-shaped path carried out, wherein on the outlet side of the photographic material in the Wide adapted to the photographic material, up and down open pipe is transported through which the photographic material is transported, the lower Dips into the immersion bath and the upper opening above the Fluid levels of the washing bath is and wherein the outlet side attached pipe above the liquid level with the inlet of the washing water connected is.

Further preferred is a device in which in the region of the inlet side of the photographic material another, designed in the same way tube attached is through which the photographic material is passed, the tube a few mm Below the liquid level through a laterally mounted pipe with the Process is connected.  

Preferably, there is at most 1/5, in particular 1/10 to 1/100, of Washing bath in the pipe. The tube dips at least as far into the tank, as it corresponds to 50% of the filling height of the tank. The maximum immersion depth of the Pipe is characterized by the extent of technical installations (pulleys etc.) limited in the tank. To under these circumstances to the particular desired, in the pipe It is advisable to use the clear width of the raw material Res set at usual tank sizes to a value of about 2 to 20 mm. The Width of the tube is determined by the width of the photographic material.

Example 1 (comparison)

A photographic color paper, each having a blue-sensitive, yellow-coupling, green-sensitive, purplish-coupling and red-sensitive cyan silver halide emulsion layer containing at least 95 mol% of AgCl (total silver halide, reported as AgNO ₃ : 1.5 g / m ² ), was exposed with a grayscale wedge and Processed as follows (standard RA-4 / AP94 process).

Developer (45 s, 35 ° C) Composition (per liter) 4- (N-ethyl-N-2-methanesulfonylaminoethyl) -2-methylphenylenediamine sesquisulfate monohydrate (CD 3) | 5 g K₂CO₃ 25 g diethylhydroxylamine 1.5 g ethylene glycol 4.0 g Nitrilotriacetic acid, trisodium salt 25 g pH 10.2 3.0 g

Bleach-fixable 46 s, 35 ° C composition Ammonium thiosulphate | 50 g sodium metabisulfite 10 g NH₄Fe EDTA 50 g EDTA acid 1 g pH 5.8

Watering in 4-fold countercurrent cascade 4 × 22.5 s, washing rate 2 l / m²

After drying, minimum density, gamma 1, gamma 2 and Maximum density measured. See table.  

Example 2 (comparison)

Procedure with separate bleach and fixer.

The procedure was as in Example 1, but after the developer was as follows further processed:

stop bath 30 s, 3% acetic acid Moire 30 s, washing rate 2 l / m² bleach 60 s, 35 ° C

Composition bleaching bath NH₄Fe EDTA | 50 g / l NH₄Br 50 g / l pH 6.0

Moire 60 s, washing rate 2 l / m² fixer 46 s, 35 ° C

Composition fixer Ammonium thiosulphate | 50 g / l called potassium 10 g / l pH 7.0

Irrigation 60 s, washing rate 2 l / m²
Sensiometric results: see table

Example 3 (comparison)

The procedure was as in Example 2, but 100 m ^{2 of} color paper were processed and kept the processing baths with matched regenerators in their chemical composition constant.

For the bleaching bath, a regenerator of the following composition was used:

NH₄Fe EDTA | 100 g / l NH₄Br 100 g / l pH 6.0 replenishment 60 ml / m²

The tank volume of the bleaching bath tank was 6 l.

By developing 100 m ^{2 of} paper was a two-time replacement of the tank volume, (by Regeneratorzufluß and Wassereinschleppung), so that in the first Nutrition an equilibrium state had occurred.

Analytical examination of the bleaching composition after processing 100 m ^{2 of} paper gave the following values:

NH₄Fe EDTA | 48.5 g / l NH₄Br 47.1 g / l

The sensiometric results after processing 100 m ^{2 of} color paper are shown in the table.

The consumption of bleach regenerator was 6.1 l.  

Example 4 (according to the invention)

Example 3 was used to process 100 m ^{2 of} color paper.

In contrast, after the bleaching bath was not watered with 2 l / m ² and the water of this processing stage was fed to the wastewater, but it was applied the following washing step. In the outlet part of the washing tank after the bleaching bath, a width-matched color paper pipe was installed, through which the color paper is fed; upper end above level, lower end narrowed by wiper lips; Length 20 cm, inside width 15 mm. The tube contains about 5% of the bath volume. The addition of the wash water takes place in the upper opening of the tube, semi-continuous with a reciprocating pump with 140 ml / m ² . On the inlet side, a corresponding pipe was installed, from which the overflow exits, a total of about 14.5 liters. This amount of liquid was combined with the overflow from the bleaching bath tank itself (5.8 liters).

The entire liquid was quenched using a slight vacuum 6 liters evaporated and used again as a regenerator.

Analysis of the evaporated solution showed:

NH₄Fe EDTA | 97.2 g / l NH₄Br 96.5 g / l.

The loss of NH ₄ Fe EDTA was therefore 6 × 2.8 = 16.8 g. The loss of NH ₄ Br was 6 × 3.5 = 21.0 g on 100 m ² paper.

The prior art is that only the overflow of the bleaching bath itself, so not the chemicals carried off by the paper were collected (5.8 l) and after Adding a concentrated rejuvenator used again as a regenerator become.  

It therefore remains in the conventional method, a loss of about 300 g of EDTA and about 300 g of NH ₄ Br by carryover.

This loss is reduced by the inventive method by about 94%. The sensiometric values after processing 200 m ^{2 of} color paper using the recovered regenerator for the second half of this amount are shown in the table.

Example 5 (according to the invention)

The procedure was as in Example 4, but the overflow of the Watering tanks pumped directly into the previous bleaching bath tank. there the concentration of the bleaching bath was correspondingly reduced. The specific one Weight of the bath was constantly monitored.

After processing of 10 m ² , the development was interrupted, the bleaching bath tank 2.8 liter bleach removed, evaporated to 1.4 l and added to the bleaching bath again.

The regeneration was carried out instead of 60 ml / m ² only 4.5 ml / m.

After processing 100 m ^{2 of} color paper and after the last evaporation process, the composition of the tank solution was determined analytically:

NH₄Fe EDTA | 51.5 g NH₄Br 49.7 g

The sensiometric check by means of gray wedge showed the in the table listed values.

Compared to the method of Example 4 are in Example 5 instead of about 20 liters only about 14 liters of water to evaporate.  

Of course, the method of Example 5 also continuously be applied so that an interruption of the development process is eliminated.

Example 6 (according to the invention)

The procedure was as in Example 3, but two washing steps were used according to Example 4 after the fixer. Using 3 metering pumps, 140 ml / m ^{2 of} liquid were pumped into the last tank and from the last to the penultimate and from the penultimate tank to the fixer bath tank.

In each case after processing about 1000 images = about 10 m ² , the processing was briefly interrupted and removed 2.8 l Fixierbad and evaporated using a weak vacuum to half. After processing 33 m ² and 66 m ² each of the entire fixing bath was subjected to electrolysis to deposit the silver.

To compensate for the anodic oxidation losses per electrolysis 5 g Potassium disulfite added, and the pH corrected with ammonia. thiosulfate was not regenerated.

After processing 100 m ^{2 of} color paper, the chemical composition of the fixer was determined analytically.

Ammonium thiosulfate 48 g / l (equivalent to the initial value) pH 6.5 silver 6.1 g / l Additional approx. 50 g of silver at the cathode.

The sensiometric values were measured after processing 100 m ^{2 of} color paper. The results can be found in the table.

Example 7 (according to the invention)

The procedure was as in Example 4, but after the bleaching bath, the washing step was replaced by a washing channel: ie the paper was through a 10 cm wide, 150 cm long, 0.3 cm high u-shaped bent, lined on the inside with polypropylene fabric Channel, whose legs at the inlet side of the paper was 10 cm shorter than on the outlet side of the paper, where 140 ml / m ^{2 of} fresh water were added by means of a metering pump. The outlet of the water was made by gravity on the side of the shorter leg, and was collected. After processing 100 m ² 8.9 cm wide color paper, 13.8 l were obtained.

These were combined with the bath overflow (6.2 L) of the bleach bath and evaporated to 6 L using a slight vacuum. This solution was again used as a regenerator and thus again processed 100 m ² color paper. Approximately 14 l of water from the channel were collected again with the bleach overflow combined and evaporated to 6 l. The following composition of this solution was determined analytically:

NH₄Fe EDTA | 98.7 g / l NH₄Br 95.5 g / l

This means that this solution still largely corresponds to the composition of the fresh regenerator and therefore can be used again. The watering channel is more efficient than the tank cascade. The sensito metric review of the process was also now again with the usual test method. The result after processing 200 m ^{2 of} color paper is shown in the table.

Sensitometric results of the examples:  

table

Claims (3)

A process for wet processing an exposed photographic recording material in continuous operation with at least one processing solution containing at least one photographic processing chemical, regenerating the working solution and rejuvenating and reusing its overflow in a conventional manner, and immediately thereafter rinsing the recording material, characterized in that the wash water loaded after the wash, loaded with the processing chemical from the preceding treatment, is concentrated to a concentration of the processing chemical at least equal to the treatment solution and added to either the treatment solution or the corresponding regenerator. 2. The method according to claim 1, characterized in that after each Be Action stage a watering according to claim 1 follows. 3. The method according to claim 1, characterized in that the Chemi washed washing water before returning it to the processing or Regenerierlösung a cleaning operation for the separation of subjected to the material originating impurities.