Patent GB-444302-A (GB)
Title: Improvements in and relating to the photo-mechanical reproduction of designs on objects having irregular or curved surfaces
IPC: G03C5/08
Filed: 1935-03-21
Abstract: 444,302. Photographic contact-printing processes ; producing photo-mechanical printing-surfaces. KODAK, Ltd., Kingsway, London.-(Eastman Kodak Co. ; 343, State Street, Rochester, New York, U.S.A.) March 21, 1935, No. 30805. Divided out of 438,960. [Class 98 (ii)] A photographic image is printed on an object having a sensitized curved or irregular surface by holding tightly stretched and extended over the surface of the object an extensible negative consisting of a thin translucent elastic sheet of a material such as rubber having an image thereon capable of expanding and contracting therewith, exposing the surface of the object to light through the negative, developing the image on the object, and if desired etching the object, and removing the remainder of the sensitized coating. As shown in Fig. 1, on a support 1 of glass, collulose derivative, waxed or waterproofed cardboard a thin rubber sheet 2 is attached by a stripping adhesive such as wax or a rubber cement. A brass, nickel or other metal foil laver 3 is attached to the rubber sheet 2 by rubber cement. A coating of a light sensitive resist such as is described in Specification 438,960 is applied to the sheet 3 and exposed under a line negative or positive. The unexposed parts of the resist are removed with kerosene, and the development is arrested by treatment with soap and water. The metal layer 3 is etched to the rubber layer 2 with aqueous ferric chloride solution of above 36‹ BaumÚ. The etched surface is rinsed with water, dried, and treated with a stain such as a rubber solution in benzene coloured with Nigrosine. As shown in Fig. 2, between the stencil areas 3<1>, 4<1> of the metal 3 and resist are areas 5 of stain directly upon the rubber. The rubber sheet 2 is stripped from the support 1 and stretched to remove the metal stencil and resist, and constitutes the negative. In a modification, the light sensitive layer is fish glue sensitized with ammonium bichromate and the stain is a rubber solution in benzene coloured with Oil Red O and Nigrosine. In another modification the design is drawn by hand in water colour on a rubber sheet, the rubber sheet treated with stain, and the water colour washed off. In another modification the rubber sheet is coated with silver halidegelatine emulsion, exposed to light behind the design, developed in a tanning developer, the untanned gelatine removed by washing in hot water, the negative stained, and the tanned gelatine stencil removed. As shown in Fig. 3, the rubber negative 10 has its ends secured together by rubber cement in an air tight seam 12 to form a cylinder, and the ends are secured between metal or rubber rings 14, 16 in each end of a glass cylinder 13. Through ring 14 at the bottom passes tubes 17, 18 provided with stop cocks 19, 20. Tube 17 is connected to a compressed air supply and tube 18 to a suction device. An article having a light sensitive coating on that portion of its surface to be ornamented is placed inside the casing and the stop-cock 19 opened while 20 is closed. The casing is mounted on a table 22 rotated or oscillated by a belt 23, and exposure effected by a light 25.