GB908237A - A method for producing explanatory texts on the frames of photographic film - Google Patents

Abstract

908,237. Etching text on film. ERTNAES, O. I. Feb. 26, 1959, No. 6784/59. Class 98 (2). In a method of producing explanatory texts on photographic film by masking portions of the film and then etching through the unmasked portions, means are provided for mixing air with the etching liquid, and directing the mixture at the film, thus removing minute gas bubbles adhering to the film which tend to prevent the etching action. In the form shown, the film strip 1, which has been covered with a protective layer removed at those portions corresponding to the lettering to be marked thereon, is passed in serpentine fashion over guide rollers which carry it through the etching liquid 5. A tube 6 passes into the liquid, and has perforations 7 arranged below the lower guide rollers. When compressed air is blown through tube 6, air bubbles emerge through the perforations, and are impelled against the film. In the arrangement of Fig. 2 (not shown), the same effect is obtained by a series of rotating vanes, which dip into the etching liquid and throw a mixture of liquid and air up against the film.