DE220154C - Process for the preparation of three-color screens for color photography - Google Patents

Description

IMPERIAL

PATENT OFFICE.

PATENT LETTERING

220154 "CLASS 57b. GROUP

Addendum to patent 216610 of November 22, 1907.

Patented in the German Empire on November 22, 1907. Longest duration: November 21, 1922.

In patent 216610 there is a method for Production of a three-color grid in a single surface layer described which consists in the fact that the area, which is divided into tanned and untanned parts, is treated with dyes dyes, one of which is the tanned, but not the untanned, two others but the untanned and not the tanned Color gelatine.

With further development of this process it has now been shown that it is not absolute it is necessary to pause the staining mode, as in that in the 216610 patent described example. Rather, one can proceed in such a way that one uses the tanned Lines with one of the dyes mentioned in patent 216610 are red and the untanned ones green, e.g. B. stained with naphthol green. From the red-green two-color grid obtained in this way

ao is washed after renewed exposure under a rotated grid from the untanned Square out the green and then color these washed-out fields with one of the untanned gelatin blue coloring dyes, as mentioned in the patent 216610 are.

This method, too, differs from that described in French patent 358250 in that a symmetrical three-color raster is produced in a single surface layer, while according to the aforementioned 35

40

French patent an asymmetrical four-color raster is achieved, which, as already in the 216610 patent, consists of two two-color grids drawn by are separated by a waterproof layer. It is, however, used in the manufacture of the The grid of the French patent also washed out the dye from untanned gelatine and replaced by another dye; but it must be taken into account that this washout was carried out twice in the proceedings of the French patent must be, in each of the two-color screens separated by the impermeable layer. The present procedure is therefore opposite to that of French patent 358250, quite apart from the fact that the Finally, the grid achieved is different, a significant simplification of the applicable Operations, which saves effort and costs and brings about a sure success will.

The following example explains the execution of the procedure:

A chromed and tanned and untanned by exposure under a black and white screen Line dissolved gelatin layer is placed in a dye bath, which consists of 10 parts an I percent solution of crystal ponceau and 20 parts of an I percent naphthol green solution consists. After about two to three

After hours of treatment in this bath, the tanned lines in the gelatin layer are red and the untanned stained green.

The gelatin layer is then turned into a. Brought chromate bath, eliminating the untanned green lines pick up chromate; after drying, under the black and white grid, copied for the second time, crossing the grid lines. Now it will be like that

ίο put the prepared grid in a bath, which consists of 90 parts of water and 10 parts of alcohol, and about 10 to 15 minutes left in it; here the untanned green fields are discolored, while a discoloration of the tanned lines and fields does not occur in this short time. The decolorization these fields would only be treated after several hours in the watery-alcoholic Solution take place. The grid is then shortened for the third staining brought into a blue dye bath, which consists of a I percent solution of brilliant azure consists; the untanned and washed-out fields very quickly take the blue dye without staining of the tanned fields. Only after several hours If left in the bath, these tanned fields would be stained.

Claims (1)

Patent claim: Execution of the patent 216610 Protected procedure, consisting in that after the renewed dismantling of the colored but untanned part of the first two-color screen obtained in tanned and untanned elements werehes out the dye from the latter and then applied a third to untanned elements Stains gelatin absorbing dye.