International photographer (Jan-Dec 1934)

Eighteen The INTERNATIONAL PHOTOGRAPHER June, 1934 Three tons of silver bullion last less than a week. These bars will soon be dissolved in nitric acid as the first step in converting silver into photo-sensitive materials for motion picture film, Kodak film and Cine-Kodak film. (Continued from Page 5) freshly washed. Purified, dustless air circulates in the room. Photographic paper has become a semi-finished product in the Kodak Park scheme of things when it emerges from the paper mill, even though it is a fine finished product in terms of paper manufacture for ordinary purposes. Kodak Park's paper must still take the sensitise coating for recording photographs, but, before that is applied an intermediate coating must go on. To isolate the emulsion from the paper, chemically pure though the paper is, is one function of the baryta coating — one or more applications of barium sulphate — that precedes the sensitive coating. A second function is to control the type of surface required for the photographic paper, of which two hundred and fifty varieties are made at Kodak Park. In the baryta coating vats, you find coating pigments that are white — not nearly white, or blue-white, or oyster white — but white — a pure, dazzling white that looks white to the eye and that the chemists say is white. When Kodak chemists declare a substance white, you can bet it is white. Paper plays an important part in Kodak's business quite aside from the actual photographic print material, for the film and the sensitized papers must be carefully packaged to protect them from light. Kodak makes its own packaging papers. Although the problem here is less acute, no less care is exercised in holding the packaging paper up to set standards than in the case of the highly refined photographic printing paper. Now for a visit to another part of the plant where purity again is the dominating note. More silver is consumed at Kodak Park than the United States Government is using in minting half dollars, quarters and dimes. Shipments of silver bars arrive daily at Kodak Park, to be kept in a large safe until they are used. Silver is ordinarily quite free from impurities, but Kodak chemists never relax their vigilance. A boring from each bar goes under analysis, for the Please mention The International Photogra slightest quantity of copper or iron must be detected and removed before this silver, transformed into silver nitrate, is ready to go into an emulsion. Beginning with the solution of silver bars in nitric acid, dusk commences to cover the operations in which silver salts are concerned. Silver nitrate is only slightly sensitive to light, so no greater darkness veils the silvernitrate operations than shading from the brightness of the sun. But when the silver nitrate goes to the emulsion department, to be combined, with potassium bromide and gelatine and other ingredients, into a diversity of light-sensitive emulsions for a variety of photographic materials, darkness falls, and thereafter all operations — putting the seasoned emulsions on the film (or paper), slitting the film into the proper widths, perforating it for motion picture camera sprockets or spooling it in the proper lengths for amateurs' cameras — go on either in a low-intensity red light or in a green light so dull that only persons accustomed to working in these rooms can see anything. Scarcely less important than cleanliness is temperature control, for variations in heat would wreak havoc on the manufacture of photographic materials. The House of Kodak, in consequence, operates refrigeration equipment far larger than that of any ice company. Many of these huge machines, each capable of producing cold equivalent to the melting of six hundred daily tons of ice, are in constant operation. Brine, cooled by ammonia, is kept circulating from the refrigeration plants through a piping system that covers many buildings in the Park. In some departments, the thermometer is not permitted to show a variation of more than two degrees all year. It is an intricate and involved business, that of making photographic materials. Kodak Park is remarkably concerned with making the present perfect. Another important question, however, is that of making the future fertile. The future, at Kodak Park, is in the hands of the Research Laboratories, with their staff of two hundred or so. From these laboratories have come marvels of photographic progress — home movies, home movies in natural color, photographic emulsions that can take pictures from hundreds of miles away, other emulsions that can take pictures in darkness, other emulsions that have greatly "speeded up" photography by artificial light and numerous refinements that have contributed to the broadening field of picture making. The Kodak Research Laboratories are a veritable research university in the field of photography. Conjure up the photographer of a little more than fifty years ago. His camera was a large, clumsy instrument. He carried with him a portable darkroom in which he had to sensitize his own plates before taking his picture. He worked under difficulties that seriously confined public interest in photography. He knew nothing of the harmful results of foreign elements in plates and paper (there was no film fifty years ago) — foreign elements that tended to spoil his materials. He knew nothing of these things except that his materials were often spoiled. The wonderful thing about him is that he didn't give up photography as a bad job. Perhaps the reason he didn't is that along came Eastman, with ideas of simplification and standardization. Eastman visualized, and established, a system of film photography that turned a difficult vocation into a simple pastime and a versatile tool. Early in his experience, George Eastman discovered through adversity, the need of pure raw materials and proper methods of manufacturing control. For fifty years the organization he founded has been working on that knowledge and refining it. For three generations, the progress has been steady toward that important goal — absolute purity of materials. pher when corresponding with advertisers.