US 2208754 A
Description (OCR text may contain errors)
AJuly 23, 1940.
J. EGGERT ET AL MULTIPACK PHOTOGRAPHY Filed Dec. ll, 1935 fo/zn Eggert Amaai mm Bz'ehr Gerd Hfeymer By /zeir Aharneys l Patented July 23, 1940 MULTIPACK PHOTOGRAPHY John Eggert, Leipzig-Gohlis, Arpad von Bichler,
and Gerd Heymer, Wolfen Kreis Bitterfeld, Germany, assignors, by mesne yassignments. to.Genera'l Aniline & Film Corporation, New York, N. Y., a corporation of Dela- Ware Application December 11, 1935, Serial No. 53,872
In Germany December 13, 1934 1 Claim. This invention relates to multipack photography.
' sion layers sensitized for One of its objects is a multipack with which sharper pictures are obtainable than hitherto usual. Further objects will be seen from the detailed specification following hereafter.` Reference is made to the accompanying drawing in which Fig. l shows a tripack of normal film and Fig. 2 shows a lenticular bipack in accordance with the invention.
In the production of multicolor pictures by means of the usual biand tripacks, there is placed in front of the second and third layer, respectively, in thepack a yellow or red filter in some suitable form, for instance, as an intermediate separate iilm or as a colored coating on the emulsion side or the opposite side of the support, or the carrier itself may be colored. The emulsion layers behind this filter are thus sensitized for corresponding kinds of light. The light filters consisting of separate films or layers interposed in the pack have the disadvantage that the distance between the several emulsion layers is increased, so that the rear pictures produced are not so sharp as the remainder. The colored support does not present this drawback but the support cannot subsequently be decolorized and therefore renders the picture unsuitable for copying. i
According to this invention there is used a fine-grained emulsion, rich in silver, which is differently sensitized for each layer, so as to produce the desired color separation. it being a'dvantageous to damp the specific blue sensitivity of the emulsion by the known method of directly dyeing the emulsion with a screening dye, for instance, a yellow dyestui. The grain of the emulsion layers in the multipack should not exceed a mean value of la diameter and the ratio of silver to gelatin should be at least l part of silver ony 1,5 parts of gelatin the partsV being by weight.
The material made by the invention is therefore without any colored layer between the emuldifferent spectral ranges; this is a, substantial simplication in the manufacture and leads to improved sharpness in the rear picture. The invention is applicable forV all tripack arrangements; advantageously it is combined with. the invention de-l scribed in U. S. patent application Serial4 No. 48,337, which deals with the'production of pictorial swollen reliefs from thin, extremely highly hardened layers of emulsion. In the tripack according to this invention the blue sensitive film is preferably arranged next the source of light, whereas the films sensitive to green and red may follow in optional manner.
The invention is also useful in the production of the two-pack lenticular lm described in U. S.
PatentNo. l1,968,944. In this case the resolution into the fundamental colors is produced in part by the iilter and screen and. in part by a spectral method with the advof diiferently colored and sensitized layers. The use of iinelygrained layers rich in silver makes it unnecessary in this case to introduce a red filter layer as has hitherto 'been usual, whereby, moreover, the assistance of the two-Zone lter arrangement in front of the objective still favours the sharp separation between the red and green details.r
In this manner there is obtained a separation of the fundamental colors which is better than when filters or sensitizers are used alone.
Fig. 1 of the accompanying drawing shows a tripack consisting of three normal films, I. 2 and 3. The front film I is sensitive to' blue, the middle film 2 is sensitive to green and the back lm is sensitive to red. Fig. 2 shows a lenticular bipack in which the lenticular front lm l is sensitive to blue and green, and the smooth back lm 2 is sensitive to red.
What we claim is:
A combination of a multipack consisting of' a lenticular film in contact with a smooth lmv and not being separated by any filter layers, each vlm consisting of a support coated with a silver halide gelatin emulsion layer having a grain size not exceeding a mean value of la diameter, the
ratio of silver to gelatin being at least l part of silver on 1.5 parts of gelatin, the parts bein'gby weight, and the .two emulsion layers being sensitized to different spectral regions.
l JOHN EGGERT.
ARPA'D von BIEHLER. GERD HEYMER..