Patent GB-190612003-A (GB)
Title: Improvements in the Design, Construction, and Manufacture of Daylight Loading Photographic Film Packs and their Contents
Inventor: THORNTON JOHN EDWARD
Filed: 1906-05-23
Granted: 1907-06-20
Abstract: 12,003. Thornton, J. E. May 23. Change - boxes ; film packs. - Relates to detail improvements in daylight - loading packets of flat photographic films of the type in which a spring division plate is employed to hold the films up to focus, and in which the films are provided with extensions terminating in film-manipulating tabs which pass through light-tight valves in the packet. The films are contained in a cardboard or metal light-tight case B, Fig. 1, having an aperture b in front, and after exposure are moved from the front to the back of the case by means of pull-tabs a or a pleated strip of paper, either of which passes through a light-tight valve in the case. Several modifications of the case and methods of manufacturing the same are described. The paper forming the pull-tab is made sufficiently long to form a tab of double thickness or two sheets may be used, which are cemented to the film at the bottom to form a retaining tab. The double tab may be perforated or punched with suitable directions, and may have a piece of coloured paper placed between the two thicknesses. Various methods of attaching the films to the tabs are described, the films being inserted in the pack alternately with separate sheets of opaque backing-paper. Several methods of connecting the films or their backings by a pleated web or strip are also described. The outer ends of the film tabs, which may be corrugated, are cut in steps and suitable stops are provided. At the bottom of each film backing or pleat or on the film itself there are cut in different positions tabs a<2>, which are laid side by side in a slot as shown in Fig. 32. Various modifications in the method of clamping the tabs and in the pressure pad and method of mounting the same are described, and means for relieving the pressure on the films may be used. Or the inside pressure plate may be omitted, the case consisting of two . shallow boxes joined by a flexible connexion. The light valve through which the tabs a pass may be formed of two pieces d of plush attached to the opposite sections. In Fig. 53 the valve D is shown packed up at the front section by a block d<5>, the back section being turned over to grip the other piece of plush. Alternatively, the valve may be formed on the central division plate, and cardboard bent or rolled into suitable forms may be used to form the two opposing sections. A number of other modifications of the light valve are described. In all cases the division plates are provided with shoulders or stops which engage with corresponding stops on the film tabs to prevent the films from being withdrawn too far. The exposure aperture b in the case B is closed by a suitable shutter G, formed of two or three thicknesses of paper and adapted to be drawn through the light valve as shown in Fig. 69. Or the cover may be formed of stiff cardboard or of thin corrugated card, metal, or cloth stiffened by cross laths. The films and safety covers may be arranged alternately in the film pack, and, when a pleated strip of opaque paper is used, the front fold is made of two or three ply. An adaptor with a covering-shutter may be dispensed with by making the latter an integral part of the film pack as described above. To prevent light from passing to the back of the pack, the face of the spring pad E and the interior of the case B are plush-covered as shown in Fig. 73. Or the spring pressure pad may be dished, or may consist of a pneumatic cushion which is adapted to be drawn over into the back compartment by means of a tab. Alternatively, the case may be fitted with a spring-pressed loose block lined with plush, or an endless band of plush passing over rollers may be used. Other modifications are described. Tabbed colours filters may be used for ortho- or tri-chromatic work, various methods of arranging these being described. They are preferably arranged to be pulled independently of the films, and the tab ends of both film and colour filters are varnished and protected by a cover or lid N which swings open under the influence of a spring as shown in Fig. 93, and may be closed with a snap after a tab has been manipulated. Several modifications are described. Each film pack may be provided with a cover which is pasted over the front face of the loaded pack by the maker. Specifications No. 4955, A.D. 1898, Nos. 10,951 and 29,631, A.D. 1904, and Nos. 11,033, 11,346, and 11,884, A.D. 1906, are referred to.