DE1190788B - Process for producing colored photographic images by the silver dye bleaching method - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

Number:
File number:
Registration date:
Display day:

GO3c

German KL: 57 b -14/02

1190 788
C 31047 IX a / 57 b
4th October 1963
April 8, 1965

The invention relates to a method for producing colored photographic images according to Silver dye bleaching method. This is known to be based on the fact that dyes, especially azo dyes, be destroyed by suitable treatment in the presence of metallic silver. The treatment is well known in a neutral to acidic containing a complexing agent and a bleach catalyst Bath.

According to the prevailing opinion, the color bleaching should be stoichiometric depending on the existing silver take place, four silver atoms are required to destroy an azo group. One should therefore assume that in a material containing several silver partial images, the gradations of the color partial images depends exclusively on the gradations of the developed silver images be. However, this is not the case. The gradations of the color sub-images are different from many others Factors dependent, such as on the type of the individual dyes, on the layer colloid, on the Layer thickness, the type of distribution of the silver within the layer and the composition and duration of the bleach bath.

It is already known the gradations of the color sub-images to steer independently, especially to make it flatter; e.g. by installing more diffusion-proof Bleach catalysts in the photosensitive layers, through the use of oxidizing agents in the Bleaching process or by using multiple dye bleaching baths.

It has now been found that, surprisingly, in the production of color photographic images achieved particularly favorable effects by the silver dye bleaching method with the help of catalysts if the development is carried out in a developer containing a color bleach catalyst, wherein the few color bleaching catalysts showing a developing effect are not used.

The photographic material to be used is, for example, a material which consists of a support, a blue-green, a purple and a yellow colored layer hydrophilic colloid such as gelatin, each of which contains a latent silver image. The material can wear the layers in a different order; it can instead of the layers colored particles contain mixed grain emulsions of the type; the support can be transparent or reflective, and finally additional layers, such as adhesive layers, intermediate layers, filter layers and top layers, to be available. This material can be used in the process of making color photographic Images made by the silver dye bleaching method

Applicant:

CIBA Aktiengesellschaft, Basel (Switzerland)

Representative:

Dr.-Ing. F. Wuesthoff, Dipl.-Ing. G. Pulse and

Dipl.-Chem. Dr. rer. nat. E. Frhr. v. Bad luck man,

Patent Attorneys, Munich 9, Schweigerstr. 2

Named as inventor:

Dr. Armin Meyer, Basel;

Dr. Rene von Wartburg, Riehen;

Dr. Walter Anderau, Aesch (Switzerland)

Claimed priority:

Switzerland of October 5, 1962 (11760)

customary emulsion additives such as wetting agents, optical and chemical sensitizers and in one or several layers or intermediate layers also contain small amounts of bleach catalysts.

According to the invention, the bath in which the latent silver image is developed contains a color bleaching catalyst. Accordingly, part of the color bleaching catalyst is removed from the layers of the in the development bath in addition to the development process treated photographic material and remains, at least partially, therein until it then takes effect during the color bleaching.

The color bleaching catalysts must not contribute significantly to the development of the latent silver image. This can easily be done by choosing developers that will bleach the color practically unable to catalyze, which applies to most commonly used developers. But you can also choose a color bleaching catalyst that does not develop a latent silver image able to meet the condition necessary according to the invention that the catalysts do not should contribute significantly to development. Both of the conditions just mentioned can also be used applicable. i.e., a developer is used that does not catalyze the bleaching of the color.

509 538/379

capable of sizing, and a catalyst that is unable to develop a latent silver image .

Preliminary tests can easily be carried out to determine whether the developers and color bleach catalysts meet these conditions. As an example of a developer without a color bleach catalyst effect , the frequently used hydroquinone may be mentioned with , if necessary, other developers to be used such as p-monomethylaminophenol sulfate .

Examples of color bleach catalysts are phenazines, such as 2-oxy-3-aminophenazine or 2,3-di- aminophenazine, but in particular the phenazine compounds of the formula

(D

listed, in which Ri is a naphthalene residue condensed with the azine ring in the manner indicated by the valence lines and bearing an oxy, amino and / or azo group on the six-membered ring not directly connected to the azine ring, and R2 one in the line indicated by the valence lines indicated manner with the azine ring condensed benzene or naphthalin radical means. Such compounds and their manufacture are described in detail in German Auslegeschrift 1,167,652.

Quinoxalines, alloxazines and cinnoline can also be used as color bleaching catalysts.

Otherwise, the new process can be carried out in a conventional manner known per se.

The dye bleach bath usually consists of an acidic aqueous solution, e.g. B. hydrochloric acid, and at least one complexing agent, ζ. Β. Potassium bromide or thiourea. Also this bath may contain bleach catalyst small quantities. However, the amounts of catalyst possibly used in the material and / or in the bleaching bath must be such that they are not sufficient for complete bleaching of all partial dye images by the image silver present in the time available.

A preferred embodiment of the fiction, contemporary process is that a light-sensitive, multilayered material free of bleach catalyst and colored with azo dyes is exposed in the usual way, then developed in a bath containing a bleach catalyst, fixed thereon, after intermediate washing in a catalyst-free one Bath is bleached and finally freed from residual silver in the usual way. The fixer between the developer and the dye bleach can also be dispensed with.

The method can also be used in reverse processes in such a way that the catalyst is added to the second development bath.

With the new process, the catalyst has a very uniform effect in the various Layers and a favorable behavior of the catalyst with respect to its diffusion achieved so that there is no bleaching of the uppermost layers, as is the case with the usual process.

In contrast to the previously known methods, the method according to the invention allows finally, to coordinate the individual color gradations with one another in such a way that one with the exposure white light, flat color gradation curves running parallel to one another are obtained, and that with Exposure to light of only one spectral color gives steep gradation curves. If So if you copy a color table that also includes a gray wedge, you get an image in which the gray wedge is reproduced correctly and in which the chromatic colors have high saturation. Should this Processes lead to excessive bleaching of the lower layers, so one can divide it up of the catalyst between the developer and the dye bleaching bath bring about a balance of the partial color images.

In the examples below, unless otherwise noted, parts are parts by weight, percentages are percentages by weight, and temperatures are given in degrees Celsius.

example 1

The following layers are successively applied to a cellulose acetate film provided with an adhesive layer applied:

1st Red-sensitive silver bromide emulsion in gelatin containing the blue-green dye of the formula

CO - HN OH

O -CH ₃

HO

H ₃ CO

HO ₃ S

contains.

2. Gelatin interlayer.

3. Green-sensitive silver bromide emulsion in gelatin containing the purple dye of the formula

NH ₂ HO ₃ S ~ _o "HO ₃ S NH ₂

HO ₃ S

Contains HO _{3 S.}

HO ₃ S

4. Yellow filter layer containing the dye of the formula

contains.

5. Blue-sensitive silver bromide emulsion in gelatin containing the yellow dye of the formula

N = N-

SO ₃ H

CH

CH ₃

SO ₃ H

SO ₃ H

and as a precipitant a mixture of a dicyandiamidine-formaldehyde reaction product, contains little sodium formate and sodium bisulphite.

6. Gelatin protective layer.

This film is shown four times behind a gray wedge.Without intermediate washing, the following stop

exposed. namely 30 fixing bath treated:

1. only with red light,

2. only with green light,

3. only with blue light,

4. with red, green and blue light,

the exposures are adjusted so that the fourth wedge is neutral gray after processing appears.

The images obtained are referred to as "red wedge" in the following. Called "green wedge", "blue wedge" and "gray wedge".

After curing in a formaldehyde bath and between rinsing, the film becomes as follows Developer developed over 6 minutes. (The temperature of the developer and all of the following Baths is 24 °.)

Sodium sulfite, anhydrous 50 g

Hydroquinone 6 g

1-phenyl-3-pyrazolidone 0.2 g

Sodium carbonate, anhydrous .... 35 g

Potassium bromide 4 g

Benzotriazole 0.3 g

Potassium iodide 0.05 g

1000 ecm of water

The following bleach catalysts are added to this developer per liter:

1st attempt

10 mg of 2-amino-3-oxyphenazine hydrochloride.

Second attempt

4 mg of 3- (4'-sulfophenylazo) -4-oxybenzo [a] phenazine-2-sulfonic acid of formula (6).

3. Attempt

6 mg of 3-amino-4-oxy-benzo [a] phenazine-2-sulfonic acid of the formula (7).

Sodium acetate 10 g

Thiourea 50 g

Glacial acetic acid 20 ecm

1000 ecm of water

After an intermediate soaking of 3 minutes, a color bleaching bath follows the composition:

Potassium bromide 100 g

Thiourea 10 g

Hydrochloric acid (conc.) 70 ecm

1.25% aqueous solution of the adduct of 35 mol
Ethylene oxide on 1 mole octadecyl

alcohol 10 ecm

1000 ecm of water

The duration of treatment in this bath is chosen on the basis of experiments so that it is just sufficient in order to completely bleach the dyes in places of high exposure in all layers. she amounts to:

1st attempt 8 minutes

2nd attempt 15 minutes

3rd attempt 15 minutes

Then it is watered with a strong hydrochloric acid copper nitrate bath, the remaining silver is rehalogenated, watered again, fixed, watered again and dried.

When this experiment is repeated, but omitting the bleach catalysts in the developer I, only an extremely low degree of color bleaching is achieved.

In three further attempts, as described above, proceeded, but omitting the developer substances 1-phenyl-3-pyrazolidone and Hydroquinone in developer I. No silver image is visible before the dye bleach bath; after finishing

During the process, no bleaching of the dyes can be observed.

The dye in the blue-sensitive layer is produced by diazotizing 2-aminonaphthalene- 4,8-disulphonic acid, coupling with 1-amino-2-methylbenzene and treating the amino- monoazo dye thus obtained with phosgene.

The catalyst 3- (4'-sulfophenylazo) -4-oxyben- zo [a] phenazine-2-sulfonic acid of the formula

HO ₃ S

is prepared by coupling diazotized 1-aminobenzene - 4 - sulfonic acid with 4 - Oxybenzo [a] phenazine 2-sulfonic acid obtained in turn by ring closure of the coupling product obtained from diazotised l-aminobenzene-4-sulfonic acid with 2-phenylamino 5- oxynaphthalene-7-sulfonic acid is obtained.

The catalyst 3-amino-4-oxy-benzo [a] phenazine-2-sulfonic acid of the formula

HO

is obtained from the above catalyst by cleavage of the azo group with sodium hydrosulfite.

Example 2

The experiments explained in Example 1 are repeated, but using the following developer II:

p-monomethylaminophenol sulfate 2.5 g

Sodium sulfite, anhydrous 30 g

Hydroquinone 2.5 g

Sodium metaborate 10 g

Potassium bromide 0.5 g

1000 ecm of water

The following bleach catalyst additives per liter of developer are used:

1st attempt

4 mg of 2-amino-3-oxyphenazine hydrochloride.

2nd experiment f> 5 4 mg 2-amino-3-oxyphenazine hydrochloride,

4 mg of 3- (4'-sulfophenylazo) -4-oxybenzo [a] phen-azine-2-sulfonic acid of the formula (6).

3. Attempt

4 mg 2-amino-3-oxyphenazine hydrochloride,
4 mg of 3-amino-4-oxybenzo [a] phenazine-2-sulfonic acid of the formula (7).

The development time is 8 minutes. The duration of the treatment in the dye bleach bath, which is enough to take on To completely bleach the dyes in all layers in places with high exposure:

1st attempt 10 minutes

2nd attempt 10 minutes

3rd attempt 12 minutes

If the bleach catalysts are omitted in Developer II , only minimal color bleaching occurs.

Without the two developer substances Metol and Hydroquinone in Developer II , no silver image is visible and there is no bleaching of the color.

B e i s ρ i e 1 3

An exposed film built up according to Example 1 is cured in a formaldehyde bath and after an intermediate wash in developer I developed for 4 minutes, the developer per Liter 30 mg of 2-amino-3-oxyphenazine hydrochloride are added as a bleaching catalyst. After a Intermediate watering of 2 minutes is treated for 4 minutes in the dye bleach bath of Example 1, the is free of bleach catalyst. According to example 1, the remaining silver is then used rehalogenated and fixed. The duration of treatment in the dye bleach bath is based on tests chosen so that it is just sufficient to level the dyes in places with high exposure in all layers to whiten completely.

For comparison purposes, a series of four exposures obtained in the same manner is used as above treated, but the developer I is free of bleach catalyst and the same catalyst (7) tor is added to the dye bleach bath in an amount of 2 mg per liter. This is just complete Fading requires 8 minutes of treatment in the dye bleach bath.

The results obtained in both experiments are summarized in the table below with regard to gradation (gamma value) and exposure range, the exposure range being denoted by Δ log E.

Δ log E = log Emax - log Emin.

Here, _n E _max and E _m i mean the strongest and weakest copy technically exploitable exposures. The color densities are measured with a Macleth-Ansco densitometer in the transparency; the gamma values correspond to the straight-line parts of the gradation curves.

f Red wedge Measuring catalyst ilogzr catalyst liog E description Gray wedge \ Green wedge filter in the developer 1.8 in the dye bleach bath 1.5 of the wedge I. Blue wedge 1.8 1.5 Red gamma 1.9 gamma 1.6 green 0.5 1.4 0.6 1.2 blue 1.1 1.4 1.2 1.2 Red 0.9 1.9 U 1.6 green 0.7 0.7 blue 1.0 1.0 0.6 0.8

10

Example 4

A multilayer, cast hardened, silver dye bleaching material cast on barite paper otherwise the same structure as in Example 1 is exposed and developed. The silver is in converted into silver chloride in a bleach bath and the resulting chloride is selectively leached out. That Remaining silver bromide is diffusely exposed and in a developer of the following composition developed during 10 minutes:

Water 750 ecm

Sodium sulfite, anhydrous 50 g

1-phenyl-3-pyrazolidone 0.2 g

Hydroquinone 6 g

Sodium carbonate, anhydrous 35 g

Potassium bromide 2 g

Sodium rhodanide 2 g

Thallium nitrate 50 mg

Water up to 1000 ecm

The layer is then watered for 1 minute and in a bath of the following composition for 8 minutes bleached:

Water 750 ml

Potassium bromide 100 g

Hydrochloric acid (37 ° / _o solution) 70 ml

Thiourea 10 g

Water up to 1000 ml

This bath contains 1 mg of dye bleach catalyst 3- (4'-sulfophenylazo) -A- oxybenzo [a] -phenazin-2-sulfonic acid of formula (6).

Then the layer is watered, and the excess silver in a known way with the help of a copper-containing bleaching bath is converted into silver chloride and this is then put in a fixing bath detached. The resulting color image shows areas of high exposure after the above treatment high color densities, while the dyes are bleached in areas of low exposure.

Example 5

This solution also contains 25 mg of the dye on photographic paper is a silver bleach catalyst 3-Amino-4-oxybenzo [a] phenazine bromide-silver iodide emulsion poured, which the 2-sulfonic acid of formula (7). 25 black dye of the formula

N = N

CH = CH

SO ₃ H

O -CH ₃

SO ₃ H

SO ₃ H

as well as a hardening agent.

A typewritten sheet of paper is thus brought into contact with the photographic paper brought that the back of the original rests on the photographic layer. In a usual The photocopier is exposed for 15 seconds and the layer in a Metol hydroquinone rapid developer, in 1000 ecm of developer 100 ecm of a solution of 1% 2,3-dimethylquinoxaline in Contains isopropanol. Then the layer is in a dye bleach bath, which is 1000 ecm Water containing 50 g of thiourea, 100 g of potassium bromide and 100 ecm of 37% hydrochloric acid. To 2 minutes a positive image of the original is created. The excess silver is then used with the help removed from a conventional bleach-fix bath.

35

40

45

so

O - CH ₃ HO ₃ S

(8th)

The addition of the 2,3-dimethylquinoxaline solution omitted to the developer, there is no bleaching of the color and a completely black one is obtained Sheet.

Claims (2)

Patent claims: 1. A process for producing colored photographic images by the silver dye bleaching method with the aid of catalysts, characterized in that the development takes place in a developer which has a color bleaching catalyst showing no developing effect contains. 2. The method according to claim 1, characterized in that a dye bleach catalyst Phenazine is used. 509 538/379 3.65 O Bundesdruckerei Berlin