American cinematographer (Aug 1933)

August 1933 0 American Cinematographer 133 Control in the Processing of Motion Picture Film by "Emery Huse, A.S.C. that exposed negatives of all types, except very special effect shots, are developed under this standard predetermined con- dition. By the test method it is necessary that the camera- man photograph an extra portion of each scene to be used as a test for development. These tests are developed for a constant time, which time has been predetermined as nor- mal for correct exposures. After the development of these tests the responsible party in the laboratory examines them and determines the time of development which in his opinion would be best suited for each take. When one considers a large production company with several individual companies in production, the number of tests which go through by this system is appreciable. Over a period of time it is found that many of these scenes receive normal development. The remaining scenes may vary from plus or minus one-half to several minutes from the normal. In many instances where scenes were shot under adverse conditions their photographic quality is materially improved by this method of negative development. The time consumed is greater and the work slightly more involved, but in view of the results obtained the quality is very favorable. The author after having observed over a five-year period the results of the development of negatives by either of these two systems is convinced that both have their merits and can be and are productive of excellent results. From the stand- point of pure sensitometric control, the developing solution itself is studied before any production work goes through it. One of the first things done when a new developer is put into the system is to run a sensitometric control, which consists of the development of a group of sensitometric strips all made under a set condition. It is determined from the re- sults of these developed strips just what time of development is necessary to give the desired control gamma. Once this is established, then regardless of which of the two systems of negative development is to be employed that time becomes the standard for that machine operating at a definite speed under a definite condition of developing solution and tem- perature. If the laboratory is operating purely on the time basis then all of the negative to be developed goes through that solution for the time which the tests indicate produces the desired control gamma. The sensitometric control which is applied to this system consists of periodic tests, such as at half hour intervals, which give data showing whether or not the degree of development was greater or less than that determined by the original test. With knowledge as - Paper delivered bv Mr. Huse at April, 1933 S.M.P.E. Convention. a result of practice which now exists in the laboratories it is a simple procedure to determine the rate at which a replenisher must be added to the developing solution to maintain it at its predetermined controlled developing power. Naturally, during the course of development by either sys- tem the developing strength of the solution changes as in- creased footage goes through it. It is necessary to find a means of maintaining the fixed development condition, whether it be by altering the time of development or the chemical replenishment. In some laboratories samples of a test negative are de- veloped along with their sensitometric strips. This test negative is usually a closeup of a girl. Many laboratory men still feel that they can see more in the pic- ture than they can be told about that picture from the data which is indicated by the sensitometric analysis. By de- veloping both sensitometric and practical tests a double check is made. It is remarkable to observe the fine details of density and contrast which can be seen by the experi- enced laboratory man in the examination of the test picture negative. All laboratory men are becoming more thoroughly educated in the art of sensitometry and are becoming quite able in determining from the sensitometric data the cause of any differences which might occur and show themselves between two successive tests. There is still in existence in Hollywood one or two smaller laboratories operating by the rack and tank method. Their system of sensitometric con- trol is quite similar to that applied to machine development. With very carefully laid down manipulative procedures good results can be and are being obtained. One laboratory in particular uses the rack and tank method for the develop- ment of all film, including picture negative and positive and sound track. However, inasmuch as we are more par- ticularly interested in the modern methods of control, we shall not deal further with any system except one which makes use of developing machines. All of the foregoing under the general heading of nega- tive development has dealt with the procedure involved. Nothing has been said quantitatively about the results ob- tained. During the past five years there have been some rather definite changes in what is desired from the stand- point of negative quality. In 1928 the author had occa- sion to measure sensitometrically the control gammas of the solutions used by the various major laboratories in Hol- lywood. This was before any sensitometric methods were in use in these laboratories. The film which was used was panchromatic negative which was then in style. The sensi- tometric exposures were made on a time scale sensitometer in the West Coast Laboratories of the Motion Picture Film Division of the Eastman Kodak Company. This instrument was a duplicate of the time scale sensitometer in use in the Research Laboratories in Rochester. The gamma values resulting from exposures made on this instrument were of the same general order as those obtained currently with the Type Mb sensitometer. At the time of these tests the average negative picture gamma was very close to .80, some laboratories running higher values. A few years ago, par- ticularly after the introduction of the high speed super-sensi- tive type of film, it was found that the trend in general negative quality was toward a lower degree of contrast, which exhibited itself from the sensitometric data made at the time. Measurements of negative gamma from .55 to .65 were quite normal. At the present time, 1933, the average negative gamma has increased somewhat and mea- urements show negative gammas falling between .60 and .75, with the average being very close to .67. It is not with- in the scope of this paper to explain why this trend has taken place, if it were possible, although it can be stated in brief that as the details of the photographic method of recording sound were improved, changes were necessitated in the en- tire processing system of both sound and picture films.