GB486360A - Improvements in or relating to the treatment of cinematograph films - Google Patents

Abstract

486,360. Renovating kinematograph films. STOCK, F. J. J. June 14, 1937, No. 16610. Convention date, June 19, 1936. [Class 98 (ii)] The marginal perforated region of developed and fixed films, more especially those of non- inflammable or slowly-inflammable material, are treated separately to incorporate softening agents therein in a manner known per se. The films may be treated over their full width, in a manner known per se, prior to or after the marginal treatment, with softening agents which swell the film to restore it to its condition when raw. A solution of substances of greater strength when solid than the film material, and equivalent physically and chemically to the film material, may be applied to the film in its swollen state to form a protective layer homogeneously united with the film surface. As softening agents may be used camphor dissolved in acetone acetic ether for celluloid films ; and for acetate films, triphenylphosphate, phthalic acid ester or phosphoric acid ester, dissolved in acetone, acetic ether or methylene chloride. For applying the liquids, the film may be led successively over three rollers which dip into baths of the liquids, and are provided with reduced peripheral portions so that the first applies softening liquid to the perforated region, the second applies the same liquid to the remaining region or to the whole width, and the third applies the protective coating. A solution suitable for the combined swelling, coating, and impregnating of a celluloid film may consist of a nitrous cellulose ester of low viscosity such as pyroxylin, shellac, and camphor, dissolved in alcohol and acetic ether. The processes described in Specifications 230,154 and 243,752, [both in Class 98 (ii)], are referred to ; and also a process for applying to a film a polyglycol and then a quick-drying cellulose ester composition ; and a process for applying to a film a coating solution containing collodion, sulphuric ether, methylated spirit, and either formic acid, glacial acetic acid, or acetic ether.