Pinatypie

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Roses (Ernst König, 1905)

Pinatypie is a process that was used from around the beginning of the 20th century to the 1960s, starting from slides, colored paper pictures and projection slides - e.g. B. for the projection of still image advertisements in cinemas - to produce. The Pinatypie process is a so-called diadirect or direct positive process , in which no intermediate negative has to be made.

The process was invented in 1903 by the French Léon Didier and developed to industrial maturity by Ernst König and other chemists at Hoechst AG . From her u. a. also produced the necessary azo dyes and fixers.

Unlike the dye transfer processes such as Technicolor 4 , the Pinatypie process was not a photographic process based on silver halides . Instead, other metal salts, in particular bichromates, are used for the photographic sensitization of the Pinatypie. For the production of this type of slides z. B. Agfa Pinatypie plates, which were panes of glass coated only with pure, uncured gelatin. The light-sensitive metal salts were incorporated into the gelatin layer by the respective processor of the plate by bathing in a potassium dichromate solution and the plate was sensitized photographically.

Strictly speaking, the coating of a Pinatypie plate is therefore not an emulsion, as the metal salt ions were not emulsified in the hot, liquid gelatin prior to the coating and the photographic emulsion does not ripen, as is typical for silver halide processes and associated with them Increase in sensitivity is necessary.

To make a three-colored Pinatypie you need 2 plates each. The two raw Pinatypie plates are sensitized as described above. Then, on one of the two plates, the red separation of the original slide is exposed the right way round and a red azo dye is attached to the metal salt image in a subsequent bath. On the second plate, the blue-green separation is exposed the wrong way round and the metal salt image is colored with a corresponding azo dye.

After the plate with the red separation has been soaked and dried, a second layer of gelatin is covered over it, which in turn is sensitized with a bichromate bath. Once the plate has dried, the red separation prepared in this way and the already prepared blue separation with their gelatin layers are placed on top of one another with a perfect fit and a yellow separation is exposed through the blue separation into the second gelatine layer of the red separation, right side up.

The two plates are then separated and the metal salt image in the gelatin layer with the yellow extract - which the red extract carries piggyback - colored with a yellow azo dye. The existing red image is retained. After drying, the plates (as already for the exposure of the yellow separation) are placed on top of each other with their gelatin side and assembled. You now form the finished Pinatypie, which can be used as a large slide for projection.

literature

Individual evidence

  1. ↑ Bäumler, 1963, p. 310