Journal of the Society of Motion Picture Engineers (1930-1949)

476 SPRING CONVENTION [j. s. M. p. E. image on a metal film. Can a metal film be joined rapidly if it conies apart? A comparison of shrinkage between metal film and cellulose film. What evidence have we of the permanence of metal film? Will it be possible to develop color on metal film, and will the use of prisms make it possible for successful projection? What changes will the operator have to make in technic and general practice? Why will the sound be more accurate from a reflected image? Will it be possible in the future to use a series of sound-tracks in various languages on the metal film? With the elimination of the fire hazard, shrinkage, and the introduction of less weight and positive permanence, what are the chief defects to be expected in metal film, and what is proposed to overcome these defects? "Documentary Film Study — a Supplementary Aid to Public Relations"; A. A. Mercey, School of Public Affairs, The American University, Washington, D. C. Documentary films are proving of increased importance as a factor for informing and mobilizing opinion. The marked success of two U. S. documentary films, The Plow That Broke the Plains and The River, both written and directed by Pare Lorentz, has focused new attention upon this type of film. The school of Public Affairs of American University conducts an "in-service" training school for government employees whereby registrants obtain instruction in courses and subjects from experts in various Federal departments. Included in these curricula are a series of courses on public relations. The film as a factor in public relations is an important one. In answer to requests for some information and instruction in this new field, a course in "Documentary Films Today" was instituted. The film course included an eightweek study with screenings, film analyses, and discussions conducted by visiting experts in film -making and film use. The subjects covered were : The newsreel as contemporary historian ; the March of Time as a document; federal, educational, and scientific films; U. S. Government documentary films; documentary aspects of Hollywood films; foreign documentaries; industrial, sales, and domestic propaganda films. During the eight-week period, visiting experts included a government producer, an industrial film user, an educator, and others. Technical aspects with reference to advances in film production were discussed. In addition to regular film discussion and study, a number of reports were made on documentary film activities. Among the most important was one on a federal film survey. For the first time, a complete survey of all U. S. government films is being made that will compile in one place the data on motion pictures. A standardized type of procedure was outlined. "The Determination of Correct Exposure in Photography"; L. A. Jones, Kodak Research Laboratories, Rochester, N. Y. Many treatments of this subject, some dealing with certain specific phases, and some fairly complete, are to be found in varidus textbooks and scientific journals in the field of optics and photography. In spite of this, however, there seems to be some uncertainty in the minds of some relative to the correct manner of dealing with the problem. The present treatment is distinctly of a tutorial character, an endeavor being made to present the problem in a clear and systematic fashion. Much of the existing confusion is doubtless due to the multiplicity of photometric units found in the literature of photometry, and to a certain amount of ambiguity