The Cine Technician (1935-1937)

Aug. -Oct., 1936 The Journal of the Association of Cine-Technicians Ov-> this discussion cannot progress without considering the developer situation is because of the fact that this developer single handedly played a very large part in the advancement of motion picture photographic quality. In photographv that chemical solution which is used to reduce the exposed silver bromide grains to metallic silver and thus make visible the effect of exposure is referred to as the de^•eloper. A developer consists primarily of a reducing agent, an accelerator in the form of an alkah, and a preservati\-e, usually sodium sulfite. This does not imply that a developing solution contains only three chemicals since there are quite a few other chemicals which may be properly compounded to produce a developer which will give the desired degree of chemical reduction of the exposed film. In the days of orthochromatic negative a de\-eloper of a type which we would now consider extremely violent in its action was used. This developer and modifications of it consisted of the use of organic reducing agents, sodium carbonate as the alkali for accelerating the action of the reducing agents and sodium sulfite in just such quantities to preserve the developer against undue aerial oxidation. It was necessary that an active developer be used because of the limitations in the speed of the orthochromatic film and in the efficiency of the light sources. \\'hen, however, panchromatic film and incandescent illuminations were both available there were certain photographic quality deficiencies prevalent which it was felt could be eliminated by a different method of compounding the developer solution. Considerable experimental work had been carried on in Research Laboratories of the Eastman Kodak Company and in 1929 a formula for the development of negative film, known as the borax developer, was offered to the trade. This developer differed materialh' from other types of negative de TECHNICIANS engaged in Film Production in STUDIO : NEWSREEL LABORATORY SHOULD BE MEMBERS OF A.C.T. The only organisation which represents the professional interests of all CineTechnicians. (Registered Trade Union No. 1996). OVER 1,000 ALREADY BELONG DO YOU? Membership Form, Annual Report and full delails from : The Association of Cine-Technicians 30 Piccadilly Mansions : 1 7 Shaftesbury Avenue London, W. 1 'Phone: Gerrard 2366 velopers in that its action was much less violent. Since it was known that sodium sulfite in excess acted as a partial solvent of silver hahdes, this fact was made use of. The borax developer consisted essentially of the reducing agents, the alkali and sodium sulfite in excess. Since a strong alkali causes a more rapid development and a greater tendency toward grain clumping during development, it was conceived that a weaker alkali would be an admirable partner for the silver halide solvent, sodium sulfite. This weaker alkali in the developer necessitated a longer time of development than had been customary with the old type of developers and this increased time factor gave the sulfite a better chance to get in its work. The combination of these two elements, namely, sodium tetraborate (borax), and an excess of sodium sulfite, produced the real working factors of this new developer. Since the panchromatic emulsions exhibited a fair speed characteristic the use of the borax developer did not cause any material disadvantages from the speed standpoint, but the advantage derived was in the form of finer grain characteristics, which more than offset what at first seemed to be slight disadvantages. Because of the solvent action of sodium sulfite the borax developer produced somewhat less emulsion speed than the previous types. The very fact that this new developer came into use almost coincident ally with the introduction of panchromatic films and incandescent light sources made the problem of finally establishing a simple routine of practice somewhat more difficult. Not only were the cameramen involved from the standpoint of new lights and new methods of lighting, but the laboratory men also were confronted with the necessity of understanding fully the functions of the borax negative developer. The fact that panchromatic film, being sensitive to the entire visible spectrvmi, allowed for very little dark Kuh-i-.\.),M" I, ...lie Pc.Tuil, No. 4(11, U obtainable in Red, Blue, iiioen, Vullow, Black, and White, as well as in solid stick form. 1 1 writes also on iJtlass, china, and metal. Price 4d each; 3/9 \" r dozen. I-'rnnl Stntionrr^. ntc. or write to ; L 6r C. HARDTMUTH (GT. BRITAIN) LTD. KOH I NOOR FACTORY CROYDON ENGLAND KOH-I-NOOR GREASE PENCILS