GB191203385A - Improved Process for Making Motion Picture Films. - Google Patents

Abstract

3385. Thornton, J. E. Feb. 10. Chromo-gelatine and like processes; kinematographic picture films.-Kinematograph films in which the picture images are in solid pigment of any degree of opacity and any shade of colour are produced without the use or aid of silver sensitive salts. The film basis of cellulose, celluloid, or paper is sensitized by coating with a colloid and a bichromate and is exposed under a positive to a strong light. In order to obtain a sufficient exposure, the two films are exposed over a considerable length, and a printing illuminant of high illuminating but low heating power such as Cooper-Hewitt tubes, is used. The printed film is exposed to moisture to render the colloid tacky and is then developed by applying pigment in very fine powder which will adhere only to the parts that have not been hardened by exposure. Coloured paints or pigments may be sprayed on, and for black pictures graphite or lamp-black are used. Moist colours consisting of similar pigments in a suitable media such as water or gum may alternatively be applied. The film is dried in a warm chamber and the surplus non-adherent powder removed. The print is now fixed' and secured against damage by a thin coating of weak gelatine solution. The film is then thoroughly washed to get rid of any trace of chromate. When the pigment used will permit the removal may be hastened by the addition of bisulphite lye, sulphuric acid, bleaching-solution, or potash alum. The film is then dried and may be subsequently varnished. In view of the possibility of shrinkage in the film, the film is not perforated until finished. Printing, developing, and perforating appliances such as are described in Specifications 26,997/11, 3384/12, 12,230/12, and 14,433/12 are used in making the films.