Patent GB-411335-A (GB)
Title: Improvements in or relating to methods for the production of explanatory titles for the pictures on cinematographic films
IPC: G03C11/02
Filed: 1933-09-11
Abstract: 411,335. Kinematograph picture films; printing processes; stencils. HRUSKA, R., 27A, Rona utca, Budapest. Sept. 11, 1933, No. 25113. [Class 98 (ii).] Titles are produced in the picture areas of a kinematograph film, more especially a film bearing a sound record in which it is undesirable to interpolate title-bearing sections, by locally removing the photographic layer wholly, or in part, by means of a solvent, after development of the film; or, in the case of coloured films, by locally applying a chemical substance which removes or destroys the colour. For example (1) the material of the layer may be removed, down to the support if desired, by local application of mineral acid or caustic alkali ; (2) the silver halide in the layer may be removed by local application of a fixing agent (cyanogen compounds, thiosulphates or hyposulphites) before developing the film, (3) the reduced silver, after developing the films, may be converted locally into a soluble silver salt (e.g. chloride, iodide, bichromate or ferricyanide) and then dissolved by a fixing agent ; or (4) in the case of colour films, the colours may be removed by local application of an agent such as an oxychloride, peroxide, chlorine water, perborate, permanganate or bichromate, which bleaches or destroys the colours, and also, if the film bears a silver key image, the silver may be locally removed as in. (3). If desired, the transparent letters formed in any of these ways may be coloured or blackened by the application of paint, ink, or dyes. The solvents or reacting solutions or compositions may be applied to the film by means of a printing form of any kind such as a roller bearing types, or engraved with letters, the letter-surfaces of the form being made of porous material such as gypsum, clay or unglazed porcelain or coated with material not attacked by the letter-producing medium ; or they may be applied through a stencil pressed against, or applied by a printing form, to the surface of the film, or a protective medium such as paraffin wax, petroleum jelly, printer's ink, gelatine, or varnish may be coated on the film, and letters may be formed therein as by stamping, or printing with a solvent of the medium or with treated type &c., thus forming a stencil on the film through which the solvents may be applied to the photographic layer as described above. The protective medium may be removed from the film after the lettering operation, or, if for example, of gelatine or varnish, it may remain thereon. Where the letters are produced by a process involving the formation of cavities in the film, a final protective coating of gelatine, cellulose esters, nitrocellulose, or varnish is applied to prevent deposition of dirt in the cavities. Reference is made to the known process of cutting the film and inserting therein a length of film bearing the title ; and also to a known process in which the photographic layer is softened by moistening it, and the letters are stamped into the softened layer by application of type bodies or printing blocks.