Journal of the Society of Motion Picture and Television Engineers (1950-1954)

but it represents a pioneering effort in the use of inorganic salts for developing photographic emulsions. Although this paper has dealt mainly with the processing of positive emulsions, some results have been obtained in other applications. In general, results with high-speed negative emulsions have been much poorer, at least when using the optimum vanadium formula mentioned. The large speed increases associated with processing positive films have not been obtained in these cases. Better results have been obtained when processing fine-grain recording materials, such as Kodak Recordak and Microfile films, but more complete tests with a wide variety of emulsions are in progress. Acknowledgment The authors are indebted to C. J. Kunz for assistance in the design of the processor. References 1. G. E. K. Mees, The Theory of the Photographic Process, The Macmillan Co., New York, N.Y., 1942, pp. 332-337. 2. E. Fuchs, "Entwicklung photographischer Schichten auf electrischem Wege," Phot. Ind., 28: 927, 1930. 3. R. E. Liesegang, "Entwicklungs-Versuche," Phot. Arch.: 282, 1895. 4. (a) J. Rzymkowski, "Titan (III)— Oxolat als photographischer Entwickler," Archiv Za Kemiju, 20: 26-45, 1948. (b) See also J. Rzymkowski, "Metallkomplexsysteme des Typus Alkj.(R»COO)tfMez als photographische Entwickler," Z. wiss. Phot., 40: 136, 1941. 5. A. and L. LumieVe, "Sur les proprietes des sels de vanadium," Bull. soc. franc, phot., 70: 108, 1894 (2). 6. Tobin, Druggist Circular, 43: 184, Oct. 1899. 7. P. Roman, "Preparation et regeneration electrolytiques de revelateurs photographiques," Sci. et inds. phot. (2), 23: 417-426, 1952. 8. L. J. Fortmiller and T. H. James (to be published in J. Phot. Sci. [Section B of The Photographic Journal of the Royal Photographic Society]). Discussion John A. Maurer (J. A. Maurer, Inc.):lt was mentioned that no sound track was made on this film. It was also mentioned during the paper that the vanadium has a hardening effect on the portion of the film where the image is developed. Of course, we're all familiar with the fact that in ordinary development an image in relief is generally produced. This relief image can be seen while the film is still wet. This action is accompanied by certain dimensional changes in the image which in the literature go by the name of the Ross effect, and which, in many cases, introduce distortion in sound recorded on film. Have any observations been made as to the magnitude of the Ross effect in the vanadium development? Mr. Rasch: We haven't made any specific investigations of that effect but the sound-track quality for variable-area sound is at least equal to that of conventional processing. From the standpoint of variable-density recording, higher intermodulation distortion levels were found. Tom Hill (Ringwood Chemical Corp., Ringwood, III.): What provisions or plans have been made for neutralizing or removing from the premises the by-product bromine gas? Mr. Rasch: The amount of bromine gas coming off was extremely small and we could get rid of it by turning it into the regular flues of the Research Laboratories. However, we have run tests in which a hydrobromic acid solution was used as the anolyte and in that case we get a much greater volume of bromine gas. However, bromine gas is absorbed very readily in a sodium carbonate solution with the release of carbon dioxide. 10 January 1954 Journal of the SMPTE Vol. 62