DE2044994A1 - Dye bleach bath for the silver dye bleaching process - Google Patents

Description

AGFA-GEVAERTAG ⁴⁴ " ⁴

PATENT DEPARTMENT LEVERKUSEN

Gs / Ws

Sep 10 197U

Dye bleach bath for the silver dye bleaching process

The invention relates to an improved dye bleach bath for the silver dye bleaching process which contains oximes ale antioxidants.

It is known to produce color photographic images by the silver dye bleaching process. The dye (or the dyes of a multilayer material), usually an azo dye, is bleached image-wise in an acidic bath in a homogeneous β inge colored colloid layer at the points where a silver image was previously produced.

Both negatives and reversal images can be produced using this process. If one wants to achieve direct positive paper images or duplicate positives from slides, one works with a simple black and white development to produce a silver image, which then represents a negative of the master copy. Since the image dye homogeneously distributed in the layer (or the three layers of a multicolor material) is destroyed in accordance with the silver image, in the end the desired dye image positive for the original is obtained (reversal image).

209812 / U33

ORIGINAL INSPECTED

2QU994

If a silver image is generated that is positive for the original (silver reversal image) E.g. through a black-and-white reversal development, bo is created after the color bleaching as a template in the gradation opposite dye image, i.e. a positive color image, if the original is a color negative.

A major disadvantage of this method is its lack of sensitivity.

Various methods have been proposed to overcome this disadvantage. So it was tried until the time of exposure only to store reaction components for the later production of azo dyes in the layers and after the Exposure and black-and-white development with suitable diazonium salts to implement the desired image dyes then be bleached.

However, this procedure has not acquired any practical importance, since there is no diazonium salt, the yellow, magenta and blue-green dyes which are suitable with three predetermined azo components at the same time supplies. In addition, diazonium salt solutions capable of coupling are too unstable for storage. Variations too these possibilities do not lead to a practically suitable process, so that there is a problem of increasing the sensitivity of photographic materials after the silver dye bleaching process still exists.

Another problem is uniformity and reproducibility the processing of silver dye bleach materials. The uniformity of processing in the dye bleach bath depends among other things, on the fact that the metallic silver formed during the previous development is exclusively the bleach catalyst reduced, which in turn reduces the azo dye.

The uniformity is now considerably disturbed by that amount of developed silver, which is not transferred in an image-wise manner, which is necessary to once again reduce oxidized bleach catalyst molecules ^{by the influence of air after the reduction by Ag 0 has taken place.}

AG 665 - 2 -

209812 / U33

ORIGINAL INSPECTED

3 20U994

A measure to switch off this air oxidation is e.g. the German Offenlegungsschrift 1 552 365 described. The air in the dye bleach bath is displaced by (constant fabric rinsing, but of course not completely switched off.

Another measure to prevent the oxidation of the extremely air-sensitive, reduced forms of the heterocyclic nitrogen bleach catalysts is described in British Patent 630,222. By adding hypophosphite to the iodide-containing dye bleach bath should prevent the air from oxidizing the hydriodic acid to form iodine. Indeed, this oxidation is reduced, but not largely, by hypophosphite enough, since the reaction of iodine and especially iodinequinoline with hypophosphite is very slow at room temperature.

The invention is based on the object of the Oxydatiohsschuts of dye bleach baths.

This has now been found in a dye bleaching bath for the silver dye bleaching process, which consists of an aqueous solution, the essential components of which are contained in water-soluble inorganic halide as a silver complexing agent, a silver complexing agent and an acid, and which is characterized in that it as an antioxidant, a Qxim in amounts of 10 to 5. 10 " Contains mol / l.

The addition of oximes to the dye bleach baths according to the invention results in a surprising improvement in the protection against oxidation. This is especially true in comparison with sodium hypophosphite, which is added to known dye bleaching baths to prevent iodine formation from iodide ions through air oxidation. The improvement can be determined in a simple manner by counting the steps of a step wedge around which the silver dye bleach material can be processed more sensitively with the dye bleach baths according to the invention. Since an effective protection against oxidation reduces the amount of non-imagewise consumed silver, this can contribute to the bleaching of the azo dyes. AG 665 - 3 -

209812 / U33

_M 20U994

Aliphatic ones are suitable for the dye bleach baths according to the invention and aromatic aldoximes and ketoximes, namely both monoximes and polyoximes. Proven to be particularly suitable cyclohexanone oxime and its derivatives, crotonaldehyde oxime, Glutaraldehyde dioxime, hexanedioxime and phthaloxime.

The concentrations of oximes in the acidic dye bleach bath can

-? ι from 10 to 5 depending on solubility. 10 mol / l fluctuate. In most cases, the most favorable concentration of the oximes is about 10 ^"1 moles / l.

The amounts of the other components of the bleach bath can vary according to the desired exposure time and the image contrast be aligned. In general, however, the amounts of the silver salt former and the complexing agent are in the range from 0.01 mol - 1 mol / l. The amount of acid used is such that any heterocyclic bases present are neutralized and that there is an excess which ensures a pH value less than 7.

The antioxidants used according to the invention can can be used in the positive-positive as well as in the negative-positive process of the silver dye bleaching process. The following Examples serve to illustrate the invention.

example 1

A multilayer photographic material suitable for the positive-positive process of the silver dye bleaching process with diffusion-resistant azo dyes in the individual layers, namely from a red-sensitive one located on a base Silver bromide gelatin emulsion layer containing a blue-green azo dye, a green-sensitive Si overbromide layer, which contains a purple dye, a filter layer and an uppermost blue-sensitive silver bromide layer which contains a yellow dye, was exposed under a gray wedge (y2) and then processed as follows at a temperature of 20 °.

- 4 209812 / U3 3

ST 20U99A

1. Developer θ ¹

2. Soaking 5 ¹

3. Hardening bath 5 «

4. Soak 5 "

5.Silver dye bleach bath 15

6. Soak 5 '

7. Bleach-fix bath 10 '

8. Soak 10 '

9. Drying -

They have the following composition:

Developer: 24 g sodium sulfite

2 g hexametaphosphate 100 g potassium carbonate 1 g potassium bromide 6 g N, N-n-Buty1- (J -n-sulfobuty1-p-

phenylenediamine 4 g hydroxylamine sulfate Dissolve substances in 800 ml of water and make up to 1000 ml.

2. Hardening bath 40 g sodium bicarbonate

25 ml Formalin 30 i »dissolve in 800 ml water and 1000 ml fill.

Silver color bleach bath: 75 ml H ₂ SO-cone.

50 ml quinoline 10 g KJ 10 g cyclohexanone oxime

Dissolve in 800 ml of water and make up to 1000 ml.

Bleach-fix bath: 14 g alkylenediaminetetraacetic acid

sodium

10 g sodium sulfite 3 »8" ethylenediaminetetraacetic acid 40 g sodium salt of the iron (III) complex

AG 665 - 5 -

209812 / U33

C 20U99A

of ethylenediaminetetraacetic acid 200 g of ammonium thiosulfate

1 ml reaction product of ammonia and

Polyethylene oxide (IMdI: 35 mol) 1.5 g thiosemicarbazide

Dissolve in 800 ml of water and make up to 1000 ml. The material processed in this way was 2 levels more sensitive than one processed in parallel, in which only 5 g of sodium hypophosphite are used in the silver dye bleach bath instead of cyclohexanone oxime became.

Example 2

The material described in Example 1 was treated in a silver dye bleach bath with the following composition:

75 ml H ₂ SO. cone.

50 ml of quinoline

20 ml of quinaldin

13 g of hexanedioxime

40 g KJ

Dissolve in 800 ml v / ater and make up to 1000 ml. The gain in sensitivity to a material that is im Sodium hypophosphite dye bleach was processed was 3 levels. Instead of 13 g of hexanedioxime you can use the same Result also 13 g of glutanaldehyde dioxime or crotonaldehyde oxime can be used.

Example 3

One for the negative-positive process of the silver dye bleaching process suitable multilayer photographic photosensitive material with diffusion-resistant azo dyes in the individual layers, namely a yellow azo dye in the topmost blue-sensitive gelatin silver bromide emulsion layer, a yellow filter layer, a purple dye in the underneath lying green-sensitive layer and a cyan dye in the red-sensitive layer below

AG 665 - 6 -

209812 / U33

20U? 94

exposed under an original and then further treated ^{at 20 ° C. as follows.}

1. First developer 10

2. Soaking 5 ¹

3. Hardening bath 5 ¹

4. Soaking 5 ¹

5.Silver bleach bath 5 '

6.Wash '5'

7. Second developer 10

8. Soak 5 '

9.Silver dye bleach bath 15 '

10. Soaking 5 ¹

11. Bleach-fix bath 10

12.Washing 10

13. Drying

The hardening and bleach-fixing baths are identical to those of Example 1, the remaining baths have the following composition

First developer: 3 g of p-methylaminophenol

6 grams of hydroquinone

g sodium sulfite

g sodium carbonate

2 g of potassium bromide

2 g sodium hexametaphosphate 6 mg potassium iodide

2.4 g Kai iumrhodanid

Dissolve substances in 800 ml of water and make up to 1000 ml.

Silver bleach bath: 10 g potassium dichromate

ml sulfuric acid cone.

Dissolve in 800 ml of water and make up to 1000 ml.

Second developer: 1 g p-methylaminophenol

3 g hydroquinone

g sodium sulfite sicc.

AG 665 - 7 -

209812/1433

g 20U994

26 g sodium carbonate

1 g potassium bromide 1.5 ml diethyl borazane

Dissolve in 800 ml of water and make up to 1000 ml.

Silver color bleach bath: 75 ml sulfuric acid cone.

50 ml of quinoline

10 g of phthaloxime

10 g potassium iodide

Dissolve in 800 ml of water and drop to 1000 ml. The gain in sensitivity compared to one in a sodium hypophosphite dye bleach bath processed material was 1 1/2 stages.

AG 665. - 8 -

209812/1433

Claims (6)

q 20U994 claims 1. Dye bleaching bath for the silver dye bleaching process, consisting of an aqueous solution, the essential components of which are a water-soluble inorganic halide as a silver salsifying agent, a Sllberkoaplexbildner and an acid, characterized in that there is a QzIa as an antioxidant in quantities of 10 " ² to 5. 1O " ^{Contains 1} mol / l. 2. Dye bleaching bath according to Claim 1, characterized in that the concentration of the oxime is 10 " ¹ mol / l. 3. dye bleaching bath according to claim 1 and 2, characterized in that that cyclohexanone oxime is used as the oxime. 4. Dye bleach bath according to claims 1 and 2, characterized in that that hexanedioxime is used as the oxime. 5. Dye bleach bath according to claims 1 and 2, characterized in that that phthaloxime is used as the oxime. 6. dye bleaching bath according to claims 1 to 5, characterized in that it is for the positive-positive process and for the Negative-positive process is used. AG 665 - 9 - 209812/1433