International projectionist (Oct 1931-Sept 1933)

September 1932 INTERNATIONAL PROJECTIONIST 11 have recorded Iwo sets of black-andwhite images taken through light filters of complementary colors — usually orange and green, respectively — a printing device registers the two sets of images on opposite sides of the duplitized positive film. The two sides are then dyed in complementary colors exactly opposite from those of the camera filters — in other words, green and orange respectively. White light from the projector, passing through the two-color film, then throws upon the screen a picture that has the appearance of natural color. [Note: The foregoing presentation of data relative to types of motion picture film may suggest to projectionists certain other questions. Detailed information on the topics discussed in this article, or on other questions relative to film stock which may arise from time to time, will gladly be given in these columns. — Editor.] Horn Placement and Porous Screen Encounter Stiff Opposition PROJECTIONISTS as a group have never become reconciled to the mounting of sound system horns directly behind the motion picture screen. This objection by projectionists as practical showmen is two-fold: first, a horn mounting directly behind the screen occasions considerable trouble in sound transmission, and, more important (2) such manner of mounting necessitates the use of a perforated screen, which in turn results in a loss of about 40 per cent of the available light and prevents the employment of any effective screen cleaning method. Perforated screens are opposed by every thinking projectionist. Carbon manufacturers have been hard put to it to satisfy the demand for more light on the screen, • and optical companies have had their troubles in this respect, too. Increased amperage and better carbons have failed dismally to overcome the severe handicap of the perforated screen. Screen manufacturers themselves do not believe in the perforated screen, but their hands have been tied, so to speak, by the insistence of sound engineers that sound system horns be mounted directly in back of the screen. Until very recently the question of horn positioning was more or less taken for granted; the sound engineers were permitted to make the decision, and projection results, insofar as screen picture quality was concerned, were left to tag along as best they could. At the recent S.M.P.E. Convention in Washington, following the reading of the report of the Sound Committee, Mr. F. H. Richardson, well-known advocate of better projection, popped the question which led to a very interesting and illuminating discussion anent horn positioning. The discussion, which on the face of the record would seem to sustain the viewpoint of Mr. Richardson, is appended hereto : Mr. Richardson; I am not convinced that there is any necessity of punching a screen full of holes, or of placing the horn behind the screen. The average audience would not be able to notice anything wrong if the horns were moved to the side of the screen instead of being placed at the center. Besides, the screen is difficult to clean when perforated. Doesn't Matter, Says Goldsmith Dr. Goldsmith (President of the S. M. P. E.) : Experiments in moderately sized rooms in the home with 16 mm. sound projectors indicate that the exact position of the loud speaker is a matter of comparative indifference. Assume a room approximately 15 to 20 feet, with the audience seated from 8 to 12 feet from the screen, the screen being 30 by 40 inches in size. The loud speaker is placed on the floor. Under such circumstances, thejoud speaker can be directly under the screen, to either side thereof, or as much as 4 or 5 feet forward of the screen toward any individual in the audience without any protest or any apparent impression on the part of the members of the audience that the sound is not emanating from the characters on the screen. The small dimensions of the room, the short times of acoustical transmission involved, and the general acoustical characteristics of the room no doubt contribute to this convenient result. Something of the same effect is found in large theaters for that portion of the audience who are not close to the screen. The exact location of the loud speaker seems to make less difference in this case. Mr. Downes (National Carbon Co.) : The holes in the screen are responsible for the loss of a great deal of light, and we have demands for more and more light. We are reaching the point where it is difficult to obtain more light from the source, and if these holes could be removed, some of this difficulty would be avoided. Mr. Kellogg (RCA-Victor Co.): I assisted in experiments at the General Electric Laboratories in some of the first efforts to make sound films. Perforated screens were not available. The loud speakers were either both on one side of the screen, or one on each side. This arrangement was very satisfactory for music, and at that time the reproduction of music was regarded as the chief requirement. When, at a later date, speech had become the chief requisite, some difficulties arose, especially when the effects of poor recordings and reverberant theaters were compounded. In the course of a series of tests for the purpose of improving the situation, we found that there was a definite improvement in the clarity of speech, when the sound came from a single source, instead of from two or more sources. With a single source, it becomes more important to locate it behind or over the screen. Although an audience may not in general be extremely critical of the location of the source, there are unquestionably times when the illusion will be marred if the sound comes from 10 to 15 degrees to one side. Mr. Edwards (Projectionist, L. U. 306) : In the case of combination houses, the screen is raised and the horns are moved to provide stage room for vaudeville. As the vaudeville ends, the curtain and screen must be lowered, and the horn towers moved back to their original positions. These operations have to be performed in semi-darkness in about 30 seconds, and it should be perfectly obvious that errors in placement can, and do, occur. Horn Angles Changed In ordinary picture houses, where the horns are supposedly permanently located, in numbers of cases the angles of the horns have been altered unintentionally by cleaners and others working back stage. These conditions are responsible for nine-tenths of the unsatisfactory sound distribution in theaters today. If it were possible to build the horns into the proscenium arch, it would obviate these difficulties without destroying the illusion and at the same time permit a much more satisfactory picture on the screen. Mr. Davee : The ability to locate sound is binaural. Most people are unable to hear equally well with either ear, and the ability of an audience to locate a sound is probably not accurate. It would be interesting to examine the ability of an average audience to locate sound sources and to apply the results of the study in locating the horns. Mr. Santee (E.R.P.I.) : Perhaps that is why the location was determined as it is. While some persons could not tell whether the horns were behind the screen or not, others were able to do so. It was agreed that it was easier to listen to the sound when it emanated as closely as possible from the image of the characters on the screen. Otherwise, there would probably be an unconscious but continued mental effort exerted by the listener to make himself believe that the sound was emanating from the speaker's lips. The conclusion was reached that the logical place for the loud speakers was as nearly as possible behind the image of the head of the speaker. Quality Not Considered Mr. Greene (Projectionist, L.U. 219) : If no complaints are made, it does not necessarily follow that everything is all right. I have never forgotten the remark of Mr. E. T. Clarke before this Society years ago: "Indignation and lack of in