DE1154347B - Photographic reversal process - Google Patents

Description

The invention relates to a novel reversal development process. Reversal development, as generally practiced, consists in exposure and development ("first development") of a silver halide emulsion, with a negative The silver image is obtained by dissolving this silver image through treatment in an acidic, hexavalent one Chromium-containing bath and in the reduction (»second development«) of the remaining Silver halide, resulting in a positive silver image. Here are the words "positive" and "negative" to understand relatively. A positive image is understood here to mean an image that the Original is in the same direction, under a negative image one which is directed opposite to the original is.

This method has the disadvantage that a very strong silver is used to dissolve the first developed silver Oxidizing agent is necessary, which some support, such as. B. paper, strongly attacks and this leads to the formation of a colored veil that is disturbing when viewed from above and also greatly changes the layer colloid. The use of a strong Oxidizing agent is particularly disadvantageous in certain processes of color photography, in where dyes or dye-forming substances are used that are destroyed by such a bath will.

It is already known to expose and develop a silver bromide emulsion, then the negative one To convert the silver image into silver chloride, to dissolve the silver chloride in a concentrated alkali metal chloride solution and to reduce the silver bromide. But can by concentrated alkali chloride solution without special Additives, especially in thick photographic layers or in multilayer materials, the silver chloride cannot be completely removed. Even after several hours of exposure to the alkali chloride solution there is still enough silver chloride present in the deeper layers for the second development Veils arise. However, if you let the alkali chloride solution act long enough (which takes an inconveniently long time) or going to a stronger silver salt solvent when alkali chloride takes effect, the silver chloride is finally dissolved out, but considerably Amounts of silver bromide, especially in the top layers of a multilayer material, will be also solved.

It has now been found that it is possible to do the whole lot even in a multilayered material of the relatively easily soluble, reversed photographic process

Applicant:

CIBA Aktiengesellschaft, Basel (Switzerland)

Representative: Dr.-Ing. F. Wuesthoff, Dipl.-Ing. G. Pulse and Dipl.-Chem. Dr. rer. nat. E. Frhr. v. Pechmann, patent attorneys, Munich 9, Schweigerstr. 2

Claimed priority:
Switzerland of December 20, 1961 (No. 14 836)

Rene von Wartburg, Basel (Switzerland),
has been named as the inventor

development of developed silver in a salt obtained silver salt without the undeveloped silver halide to attack. This succeeds if the undeveloped silver halide is replaced by certain substances according to the invention Measures against the silver salt solvent passivated.

The invention accordingly deals with the improvement of a reversal photographic process for the production of a silver image in the same direction as the original in a photographic material which contains at least one light-sensitive emulsion consisting of a silver halide, whereby by Exposure and initial development first creates a metallic silver image, then a transformation of the metallic silver image takes place in a more easily soluble than said silver halide silver salt image, which Silver salt image is dissolved out with a silver salt solvent and reduction of the undeveloped Silver halide takes place. The invention is characterized in that the material is used at the earliest according to the invention after the first development and at the latest during the action of the silver salt solvent is treated with a compound, which with silver is even heavier than the original Forms silver halide soluble silver compound. The resulting silver image can then, as further below, can be converted into different types of images.

309 687/236

3 4

The light-sensitive emulsions contain both those of the lower layers and the fixation for example silver bromide, preferably of silver salt emulsion, is delayed more than coarse-grained silver bromide. That of silver converted into silver salt is particularly advantageous. Results are achieved with iodide-rich silver bromide - this enables the selective fixation of silver emulsions achieved, but can even silver chloride 5 chloride in the presence of silver bromide in Silver bromide emulsions can be used. thick layers or in multilayer materials

The metallic Hen developed in the first developer enables.

Silver images are preferably made in silver chloride- A delay in fixing in the lower Images converted, for example by a strong layering, can in particular thereby cause salt acid Copper nitrate bath or by a bath, ίο the fact that you can add a fixer to the fixer Potassium ferricyanide and sodium chloride decelerators, such as ethylenediamine, are added, whereby holds. a uniform preferred solution of the silver

The silver salt solvent or fixing bath is preferably one in the entire depth of the material, which has a stronger effect than a better one, without the pass-concentrated alkali metal chloride solution being noticeably hindered, for example ammonia, a sulphite, a thiourine, or a thiosulphate is included in the process according to the invention. For example, the light-sensitive silver bromide emulsions, neutral to weakly acidic _{baths containing sodium thiosulphate s} j _O n after removal of the silver chloride images, have proven to be best. made windable. This is done with advantage

A diffuse exposure for the passivating treatment of the indentation. Then the silver bromide

wrapped silver halide compounds emulsion in the second developer to metallic silver

can e.g. B. iodides (such as potassium iodide, sodium iodide, reduced. Now it has been shown that the

Ammonium iodide, hydriodic acid) or the aforementioned passivating agents

capto compounds, especially heterocyclic merid, is more difficult to develop than it was before loading

capto compounds (such as mercaptobenzimidazole or 25 act. This phenomenon can be caused by

Mercaptobenzothiazole) or other compounds can easily be remedied that the second developer

which very sparingly soluble silver compounds _ER-e is added in the silver salt solution Mitel; through this

give. These compounds reach the _w i _{r (} j that the passivated silver bromide,

Conversion of the first developed silver into an even strongly iodized silver bromide, without any difficulty.

Silver salt specific fixer, e.g. B. in a stop 30 can reduce speed.

bad after the initial development or in a special The necessary amounts of poorly soluble

bath after the stop bath, for the action and / or substances forming silver compounds, the

can also be added to the fixer. Very composition of the fixer and the duration of the

good effects can also be achieved with baths. Treatments are natural from each other and also

those that contain several of these compounds or depending on the layer thickness and the hardening, so

if one of these compounds is in the stop bath and one that the optimal ratios on a case-by-case basis

other is present in the fixer. For example, it must be determined experimentally

Fixing baths are used with success, which per liter The silver-

0.01 to 0.05 g of potassium iodide and 0.05 to 0.5 g of images can be used as such: they

Contain mercaptobenzimidazole. 40 can also be used in connection with others

The results achieved by the new method are used methods, e.g. B. those where

are surprising. In particular, it was not prior to the first development and / or the second development

look that the undeveloped silver halide is a chromogenic development or those

is more passivated by these compounds than with the metallic

the silver images 45 developed through re-halogenation see silver carry out further reactions

produced silver halide and that the solubility den. The process is therefore for the production of

difference between these two types of silver salt gradation masks, integral color correction masks,

increases. Key printing, color film soundtracks, etc. suitable.

There is also another effect of the poorly soluble substances that can form silver compounds are noteworthy after the process according to the invention: In the absence of these substances using the silver dye bleaching process, an ordinary fixer has a stronger effect on the above original color images to produce, ren layers than on the lower layers of a. B. between a silver chloride image in 55 silver, whereby a lower layer and a silver bromide image in color image are created in the opposite direction to the silver image. It will therefore be even less in the usual one top layer than in those employing the silver dye bleaching process of cases where both images are at the same depth. The positive original, a negative silver image and treatment according to the invention acts now finally produced in this a positive color copy undesirable phenomenon characterized corrective that 60 D _{a now} j _n the practice of color photography the solubility of all the silver halides in the upper negative recording method more and more of Be -Layers is sufficiently inhibited so that an interpretation is gained, are better methods of making positive copies of the silver chloride image in a deep layer beneath these negatives, e.g. B. Supervision conditions can be resolved under which a picture, to produce, urgently desired. The er silver bromide image in the top layer is not yet attacked in an excellent way for this purpose. suitable. It is only necessary, in the treatment given above, the way in which a silver image in the same direction as the original fixation of the upper layers is delayed more than it is produced, and this leads to the destruction of a pale

able to use dye. Since this is a negative process in which the spatial The distribution of the dye in the final image corresponds to the distribution of the primary developed silver, the process has the particular advantage that it has the casting accuracy and quality The requirements of the casting base are less stringent than with a reverse process, where the spatial distribution of the dye in the final picture of the distribution of the residual halogen silver after the first development.

Since most of the dyes suitable for the silver dye bleaching process are produced by strong oxidizing agents, like acidic bichromate baths, are destroyed while they are e.g. B. not by a hydrochloric acid copper nitrate bath are attacked, the usual dyes can be used for this process.

The process is also particularly interesting because the presence of dyes that can be bleached by silver (and especially of diffusion solid dyes) prohibits the use of other theoretically possible methods. So fail many oxidation baths, which are a substitute for bichromate baths that are otherwise used Can dissolve silver salts in the absence of diffusion-resistant dyes. Probably similar The reasons are the solubility of silver chloride in alkali chloride solutions or the leachability of the Silver salt-alkali metal chloride complexes are considerably reduced by the presence of dyes.

The preferred application of the invention is therefore to produce a color image that is opposite to the original to produce by the silver dye bleaching process, in a photographic as described above Material containing at least one dye that can be bleached using the silver dye bleaching process, A silver image aligned with the original is generated and this is converted into a color image in a known manner converts. So it is carried out after the second development, the color bleaching by z. Am treated with an acidic bath containing a complexing agent and a color bleach catalyst. Last the remaining silver still present in the material is removed in a known manner, e.g. B. by treated in a hydrochloric acid copper nitrate bath and then in a fixing bath.

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

A red-sensitized silver bromide emulsion is poured onto a baryated photographic cardboard, which the blue-green dye of the formula

HO, S-

H ₉ N OH

SO ₃ H

H, CO

HO ₃ S

contains. A thin layer of gelatin is poured on top. This is followed by a green-sensitized silver bromide emulsion, which is a purple dye of the formula

NH ₂

H ₅ N

VNH-CO-C

-NH-CO-HN- (VCO-HN

OH

SO, H

HOoS

-NN- ..
HO -;

SO, H

HO, S

contains. A layer of gelatin, which contains a yellow filter dye of the formula

/ —CH ₂

V-CH ₂

, C = N

SO "H

- CH = c;

C-N- /

Cl

contains, poured. Finally, an unsensitized emulsion follows, which contains a yellow dye of the formula HO ₃ S-; XN = N- / ^X -NH-CO-HN-VN = N- <\ -SO, H

HN-COCH ₃

HN-COCH ₃

contains.

Claims (1)

7 8 A color negative Example 3 is placed on a paper so basted in an enlarger in the usual way and way copied. The procedure described in Example 1 is followed. At The paper will be in a developer the follow- ing place of 2-mercaptobenzimidazole the composition developed for 8 minutes: 5 first stop bath and the first fixing bath 0.2 g each Sodium sulfite added to 50 g of 2-mercaptobenzothiazole. 1-phenyl-3-pyrazolidone 0.2 g Hydroquinone 6 g Example 4 Anhydrous sodium carbonate .... 35 g ,, _ ».., _ ,. .._ .., ^, ~ Sodium rhodanide 2 g ¹⁰ The procedure described in Example 1 is repeated. To- Potassium bromide 2 ε in addition to the mercaptobenzimidazole or instead Water '^ j _s jQQo jui from this 2 g of potassium are added to the first stop bath ". ' iodide added. If desired, 0.01 g of potassium iodide can be added to the developing bath. After 8 minutes, 15 example 5 The development process takes place in one bath the following composition stopped: The procedure as indicated in Example 1 is stopped. At Acetic acid 20 ml place of a silver bromide emulsion is poured Sodium acetate 10 ε of ^the layers a silver bromide-silver iodide emulsion 2-mercaptobenzimidazole (given! ² ° Z * ™ ^end ?}> ^We S ^{e 96} ' ⁸ ° ^{/ o silver br} ° ^{mid and 3} ' ^{2 <) /} » if in the form of a methanolic silver iodide. Solution) 0.5 g Water up to 1000 ml Example 6 After watering for 3 minutes, the developed procedure is carried out as indicated in Example 4. At Silver in a bath of the following composition of a silver bromide emulsion is used to cast the Conversion into silver chloride: Layers of a silver bromide-silver chloride emulsion Hydrochloric acid (37 »/ 0) 90 ml ^^ •• T *? ^{6, 96 '3 <V} ° ^{Süberbromid and 3' 7} ° ^{/ o} Contains copper nitrate 135g silver chloride. Citric acid 35 g ³ ° ^{WATER UP TO} 1OOOML PATENT CLAIMS: After soaking for a minute, it will Silver chloride formed in a bath of the following 1. Reversal photographic process for Her composition solved without the remaining position of one of the original aligned borrowed silver bromide would be significantly attacked: silver image in a photographic material, the at least one light-sensitive, from one 2-mercaptobenzimidazole contains 0.5 g of silver halide existing emulsion, Sodium metabisulphite 20 g by exposure to light, initial development into one Sodium thiosulphate 50 g 40 metallic silver image, conversion of the metallic Potassium iodide 0.05 g see silver picture in a lighter than said Water up to 1000 ml of silver halide soluble silver salt image, dissolving out of the silver salt picture with a silver salt After a soaking time of 5 minutes, solvent and reduction of the undeveloped the layer 3 minutes of exposure through a 45 silver halide, characterized in that 500 W lamp exposed and in the already mentioned the material at the earliest after the first development developer 10 minutes developed, the development and no later than during the action of the interrupted in a 2% acetic acid and coated the silver salt solvent with a compound Watered for 3 minutes. It is a matter of which silver is still difficult to dissolve. After that, the dyes are more soluble in a bath than the original silver halide following composition image-wise bleached: Forms silver compound. 2. The method according to claim 1, characterized Potassium bromide 100 g indicates that emulsions are used Thiourea 50 g consisting essentially of silver bromide, Hydrochloric acid (37%) 70 ml 55 that the metallic silver image in a silver chloride 2-Amino-3-oxyphenazine 0.001 g image is converted and that as a silver salt-water A bath containing thiosulphate is used up to 1000 ml of solvent. After 10 minutes of soaking, the method according to one of claims 1 Layer remaining excess silver by a 60 and 2, characterized in that emulsions Copper nitrate bath, as described above, can be used in silver, which essentially consists of coarse converted to chloride and then consist of granular silver bromide, fixed in an acidic fixer. A fourth method according to one of claims 1 is obtained Color negative complementary positive color image. up to 3, characterized in that as difficult At n'el 2 ^6s, substance forming soluble silver compounds "an iodide is used. The procedure described in Example 1 is followed, using 5. The method as claimed in one of claims 1 but no 2-mercaptobenzimidazole is added to the stop bath. up to 3, characterized in that as difficult Substance forming soluble silver compounds is a mercapto compound, preferably one heterocyclic mercapto compound such as mercaptobenzimidazole or mercaptobenzothiazole is used will. 6. The method according to any one of claims 1 to 5, characterized in that the sparingly soluble Substance forming silver compounds is added to a bath after the first developing bath and before the silver salt solution bath. 7. The method according to any one of claims 1 to 5, characterized in that the sparingly soluble Substance forming silver compounds is added to the silver salt solution bath. 8. The method according to any one of claims 1 to 7, characterized in that a multilayer photographic material is used. 9. The method according to any one of claims 1 to 8, characterized in that at at least one of the two developments also develops a color image. 10. The method according to any one of claims 1 to 8, characterized in that emulsion layers are used, which according to the silver dye bleaching process Contain bleachable dyes. 11. The method according to claim 10, characterized in that the original is rectified Silver image after the silver color bleaching process into a color image opposite to the original is converted. © 309 687/236 9.