DE593965C - Method for producing washout relief images - Google Patents

Description

The invention relates to photographic photosensitive layers for Production of relief images using the washout process.

The main purpose of the invention is to provide a photosensitive layer for the production of To create relief images after the washout process, which are exposed from the layer side can be, in contrast to the previously required method of exposure of the support side.

Another purpose of the invention is to provide a method by which both sides of a double-coated picture film washed out for a two-color cinema film can be.

Further purposes of the invention will emerge from the description below.

In the usual process for producing gelatin relief images according to the Wash-out processes, such as carbon printing or bleaching processes with bichromate solutions, the exposure must be carried out through the support.

The latter is impossible with double-coated motion picture films and with other types of copy materials, especially paper, is very disadvantageous.

All of these difficulties are particularly addressed by the use of the present invention treated photographic emulsion layer eliminated which practically than in their Sensitivity can be addressed across the thickness changing layer. The sensitivity is greatest in the vicinity of the layer support while it is on the surface is the smallest. Such a layer can be said to be topographical, d. H. has graded sensitivity in thickness, d. H. the sensitivity changes with the distance from the boundary surface. When using the Treatment method can be assumed that the layer is topographically graded Has solubility, since after bleaching the layer on the surface is the lightest and in the vicinity of the carrier is most difficult to detach.

After the copying surface has been prepared in this way, the emulsion layer becomes exposed in the usual way from above. After developing, the image is dense and becomes closest to the support weaker towards the surface. The highlights are therefore only on the positive image Layer carrier side visible, while the deepest shadows penetrate to the surface can. After developing the silver halide image, the silver image becomes one in one Bichromate bleach bath treats the gelatin according to the amount present of the silver is hardened. When the area is now exposed to warm water is exposed, becomes a on the carrier

Relief image achieved. The latter is in close proximity to the wearer and adheres firmly this, in contrast to the relief images produced by known processes, which, when exposed from the emulsion side, lie on the surface, while the lower layer is outside soluble gelatin. The remaining silver salt is carried out in the usual way by a

to sodium thiosulfate solution removed. The resulting clear relief image can be used for Purposes of color photography to be colored. ■ ■ ■ The special one, which is used according to the invention, is topographical in its sensitivity graded emulsion or layer can be made in various ways. Two general methods of making them are given below as an example specified.

B e i s ρ i e 1 ι

An ordinary emulsion can be treated with a solution applied to its surface, thereby reducing either the actual sensitivity of the emulsion or the developability of the latent image. The solution is applied so that it has the greatest effect on the surface, while its effect decreases with the depth of the emulsion. Suitably is a 4 ° / _o sodium potassium iodide use, for about 15 sec. Or layer according to the type and strength of the emulsion, is brought for a shorter or longer period of time to act. 15 seconds are sufficient for an emulsion for the usual slide plates. The emulsion layer is then washed under running water and dried.

Desensitizers and inorganic oxidizing agents are other for this Purpose useful substances. Substances of this type are solutions of pinacryptol green, phenosafranine, iodine, chromic acid and copper chlorides dissolved in bromine ammonium. The mentioned Desensitizers are in a 75 to δοθ / o alcohol, better than in water, dissolved, whereby swelling of the gelatin is avoided by the alcohol, whereby the penetration of the solution would be limited. The one that reduces the sensitivity to light The solution can be applied to the emulsion with a brush, or the Emulsion can be dipped briefly in the solution or with one containing the solution Gelatin coated. For the latter purpose, an aqueous solution of gelatin is used and the photosensitivity reducing substance applied to the emulsion, being the reduction of photosensitivity during the short period of time up to takes place to dry the gelatin layer.

B e i s ρ i e 1 2

Another method of making the coating of topographically graded Sensitivity consists in the fact that a photosensitive dye, in particular, a dye which is strongly adsorbed by silver bromide is applied whereupon the emulsion is applied to this layer. The dye diffuses through the emulsion and makes the lowest layers most sensitive to light while hitting the surface of the Emulsion has almost no effect. Copying is done primarily with rays the color for which these dyes make the emulsion photosensitive. The contrast and density of the emulsion can be reduced to some extent regulated that some rays from parts of the spectrum are allowed for which pure silver bromide is sensitive.

Orthochromes may be used as photosensitizing dyes suitable for this purpose T, called Ethlyl Red, Isoquinoline Red and Naphthacyanol. These dyes are in an aqueous gelatin solution dissolved and applied to the carrier below the emulsion.

After a suitable emulsion surface has been prepared, the procedure is followed according to the invention in the following way to the end. Of course that is manufactured If necessary, the layer has been washed and dried beforehand. This sensitive The layer is then exposed in the usual way from the emulsion side. This is done for about 2 minutes in one vigorous developing bath containing hydroquinone and caustic soda. Finally, the copy is washed for about 5 minutes, after which it is put in a For example, the following components containing solution is bleached.

Solution a

Ammonium dichromate 20 g,

Concentrated sulfuric acid .... 14 ecm, Water until 1 1.

Solution B

Sodium chloride 48 g,

Water until 11.

Each ι part in 6 parts of water is used from solutions A and B.

It should be noted that no potassium ferricyanide is used in the method according to the invention containing bleach is required, such as a solöhes in the ozobromine process or

is necessary in certain other processes which require a dichromate bleach ■ is used to make a gelatin layer indissoluble. Becoming through the silver the bichromate ions are reduced to chromium ions, creating a tanning pattern in place is produced.

After bleaching, the relief image is made by immersing it in water of a temperature developed from 43 to 49 ° C. The fume cupboard is then dissolved in sodium thiosulphate fixed to remove the remaining silver halide. The print is washed and can then be used for any purpose for which a gelatin relief image is suitable suitable.

In certain cases it is not necessary to put the silver image in an oxidizing bath, z. B. the specified bichromate bleach to bleach. The latter applies to cases in which the layer is used for. copying by suction. To the use To avoid a bleach bath, a so-called tanning developer can help develop be used, as such have been described many times in the literature. A particularly suitable developer is a pyro developer that has little or no sodium sulfite contains. Hydroquinone or paraminophenol can also be used as a developer. When developing with a Such a solution transforms the image layer into a layer that is topographically graded Has solvability and is easiest to solve at the point at which most of the silver was present. After this process stage, the relief image be developed by washing out in warm water in the manner described, whereby the bleaching can go away. Of course, the picture can also be bleached, creating a highly insoluble image prior to dissolving the undissolved gelatin is achieved.

In order to use the method according to the invention to obtain positives from two-color cinema images produce, is proceeded in the manner described above, with only minor changes must be taken into account. A transparent carrier is used, both sides of which are connected to one of the ones described above Way produced layer are provided. For example, a page is copied from the green, the other from the red partial negative. The remaining procedural steps are then carried out simultaneously on both sides by dipping until the finished relief is achieved on each side will. Finally, each side is made up for itself by swimming in dye solutions colored complementary colors, whereby a finished color cinema film is achieved.

The invention can of course also be used for purposes other than double-coated Movies, e.g. B. can be used for a print on paper in monochrome. By the examples given are not intended to limit the invention, as modifications manifold types can be made without departing from the essence of the invention.

Claims (7)

Patent claims: 1. Process for producing washout relief images, characterized in that a layer of thickness graded sensitivity with the highest Sensitivity exposed in the vicinity of the substrate from the emulsion side, from this an image of graduated solubility is generated in the layer and then those close to the surface more easily soluble parts of the layer are washed out, creating a near deg the layer support lying, firmly adhering to this image is achieved. 2. The method according to claim 1, characterized in that the silver image after the development and before the sel ^r ash advantageously in an oxidizing agent, an acid and a soluble halogen-containing bath is bleached. 3. The method according to claim 1, characterized in that to achieve the in the thickness graded sensitivity two layers are arranged on top of each other, of those of the lower layer on the substrate, the one above it Layer sensitizing agent that penetrates to a considerable depth, z. B. a dye is added, 4. The method according to claim i, characterized in that one with a potassium iodide solution surface treated SiI-überhalogenenschicht is used. 5. The method according to claim 1, characterized in that one with desensitizers surface treated layer is used. 6. The method according to claim 1 and 2, characterized in that the image in a tanning bath is developed. 7. Application of the method according to claim 1 to 6 on coated on both sides Movies.