Motion Picture Herald (Jan-Mar 1954)

faces between these intersecting points and the rear of the auditorium can have architectural decoration. Figure K-2 is a longitudinal section of an auditorium showing the portion of the ceiling area which falls into the critical area. A comparatively small portion of the ceiling area is affected in a single-floor theatre. The viewer will not be conscious of any ceiling area which falls above a 15° angle subtended from a true horizontal eye line, as indicated in the diagram. WITH UPPER TIER SEATING Figure K-2 also shows the amount of ceiling area affected where an upper tier of seating exists, in which case a considerable amount of the ceiling area is affected. In general, however, ceiling areas that are more or less parallel with the floor are seen in what might be termed a “skim view” (foreshortened), in which case it is not necessary to make changes in shadowforming breaks. In both of the plan and section diagrams, the material within visual angles are shown as Zones A, B, and C. The projected picture is Zone A; Zone B is the immediate picture surround (for a picture width occupying a subtended angle of 20°, the surround would occupy a 5° subtended angle at each side of the screen ; and its angle should be increased to 7° if the screen occupies about a 25° subtended angle). This Zone B is shown as a shaded area in the diagrams. The light intensity in Zone B should provide a transition from screen light intensity to the intensity of screen light reflected from auditorium surfaces in Zone C. Figure K-3 indicates existing and altered wall surfaces in Zone C. The surfaces marked X are the most troublesome because they are completely turned away from light reflected from the screen, and in addition to making a dark area, they cause a shadow to be cast on the adjacent wall surfaces. A surface (Y in the same drawing) can be erected to eliminate this shadow condition. Such an angled surface will re-reflect screen light. CONSIDERING EXIT DOOR In some instances there may be exit doors included in the surfaces marked X, in which case the new surfaces Y would have to start above the height of the exit doors. Since the enlarged screens have most of their height above the top of such exit doors, it is still advantageous to provide these angled surfaces starting at the top of the doors. Sketch SK-\ illustrates an auditorium having conventional screen with black masking, and with Zone C untreated for use and control of re-reflected screen light. SKETCH SK-l: An auditorium in the conventional picture having dark masking, as it appears during the projection period. Auditorium surfaces show a dim but discernible decorative pattern, which invades vision actively enough to weaken illusion. Compare with Sketch SK-2. SKETCH SK-2: An auditorium with projection as in Sketch SK-l, but with synchronous picture light surround and neutralization of adjoining auditorium surfaces. Under these conditions the picture can dominate perception and therefore have "presence" and optimum realism. In contrast, the conditions illustrated in Sketch SK-2 contribute to concentration on the picture and thus to realism. It is highly desirable to place the bottom of the picture as close to the platform floor as possible in further aid to realism. Where this is not possible, the space between the bottom of the picture and the platform should be treated as prescribed for the X and Y surfaces as indicated in Figure K-3. In Sketch SK-2 is indicated the Zone C area shown in Figure K1. Note the complete elimination of all decorative detail. The auditorium as a whole need not have an undecorated feeling since, as can be deduced from Figure K1, there are many surfaces to which decorative material can be applied. BETTER THEATRES SECTION 21