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Bipacks double-layered sensitive films

L (A) and the first orthochromatic film (black and white), on which both green and blue rays are recorded.

During the research stages that were trying to simplify color imaging, it was seen to replace the films that carry three sensitive layers, with others that carry only two sensitive layers only, based on an idea that called at that time to suffice the separation of the colors of the white rays into two parts only, each of which is recorded on a special sensitive layer and on a support. Independent:

B As for the second film, it is a panchromatic (black and white) and the red, orange and yellow rays reflected from the flowing objects are recorded on it.

photographed.

And in the camera, the two films are shown together, face to face. The support of the first orthochromatic film is facing the lens, so the rays pass through the support. (Which is covered from the back with a very thin gray layer to prevent halo without affecting the speed of the film sensitivity).

Only green and blue rays are recorded on this film, and since these rays also affect the second panchromatic film (in contact with the first film), therefore the first orthochromatic sensitive layer is covered with a very thin layer of red-orange color that acts as a filter to absorb blue and green rays.

Accordingly, through this filter, only red, yellow and orange rays pass into the panchromatic film.

After the filming is done, each of the two films is shown in the usual black and white display solutions, so we get two negatives separated by these colors. Then they print a contact printing to obtain positive images that are also separated by colors, and then dye each of them with a suitable dye of a color complementary (1) to its original spectral sensitivity according to a method known as the Dye Toning Process (we will talk about it later in the study of methods for printing colored images), And so they become

They are valid for viewing directly by a projector. The quality of the final color images that you obtain according to this method will not be at the same quality level as other color imaging methods that rely on color separation and recording on three films. There is no doubt that.