Patent GB-392987-A (GB)
Abstract: 392,987. Colour photography and kinematography. I. G. FARBENINDUSTRIE AKT.-GES., Frankfort-on-Main, Germany. Dec. 10, 1931, No. 34308. Convention date, Dec. 10, 1930. [Class 98 (ii).] A process of printing by contact on a sensitive lenticular film colour record images which have been made on one or more non- lenticular films consists in placing the colour record images one after another on the embossed face of the lenticular film in exactly the same position and illuminating each in turn through its back by light whose angle of incidence is changed for each record so that the elementary colour records are printed in their appropriate positions under each lenticle. In the case of kinematograph films, accurate registration is effected by catches on the printing-apparatus engaging the feed perforations of the films, and in the case of ordinary photographs, the colour records to be printed and the printing material are provided with cuts, perforations, or indentations as guides to registration. The illuminant comprises glow-lamps, or illuminated slits or strips of frosted glass which may be adjustable in intensity and position, and which, for printing each record, are placed in that position relatively to the film which will be occupied during subsequent projection of the lenticular film by the virtual image of the corresponding area of the colour-selecting filter. Fig. 3 shows, for example, the printing of the red record from a negative F on to a lenticular film A, using a diaphragm R having an illuminated slit E, Fig. 2, lying within the area corresponding to the red area of the aforementioned projecting filter. The size of the sources of light depends on the nature of the lenticles on the sensitive film and of the optical system to be used in projecting the finished positive. These factors are discussed in the Specification, and preference is expressed for punctiform light sources placed at the centres of the areas referred to, and also for linear sources at right-angles to the direction of the lenticles of the films, as shown at E in Fig. 2. If it is impossible to arrange the light sources sufficiently close together for printing the several colour records, lenses which produce virtual images of the sources in the desired positions may be interposed between the sources and the film. Alternatively, a single light source may be used which can be moved to occupy the different printing positions in succession. Straight-filament lamps (a) having three separately-energizable sections and (b) having a single section, the lamp being displaceable into the three different positions, are described in the Specification. The intensity of the printing light may be varied by including resistances in the lighting circuit; by interposing grey filters, wire nets, &c., in the path of the beams, or by masking the sources themselves. The colour records to be printed from may be negatives or positives, lateral inversion being avoided during printing by placing the record against the lenticular surface of the sensitive film with its back or its image face in contact therewith according as to whether the record is a negative or a positive, or by adopting known methods in taking the records or in projecting the finished lenticular film. If the sensitive film has lenticles of such size that the elementary colour records printed under each lenticle are separated by a blank space from those printed under its immediate neighbours, these spaces may be blocked out either by the use of additional printing light sources of appropriate size and position prior to, during, or after the main printing operation, or by first printing intermediate positives on to a non-lenticular film having preferably a flat gradation, then printing, from these positives, negative records on to the lenticular film, which preferably contains a yellow dye in its emulsion layer, and finally reversing the negatives to positives by the known process, so that the blank spaces are blackened during the reversal. Reference is made to known processes of printing by contact, on a non-lenticular film, component colour records made on a lenticular film (as described for example in Specification 353,121) ; and of printing by projection, on a lenticular film, component colour records made on a non-lenticular film.