Motion Picture Herald (May-Jun 1946)

Schematic drawing indicating neutral treatment of auditorium in the screen area, where surfaces should not compete with the picture for attention. Downlighting is here suggested for illumination, while corrugated areas to right and left of screen diffuse screen light. The rest of the walls should be of neutral tones, decoration being confined to the rear portions. there are no regulations governing theatre construction. This arrangement provides even greater safety in case of emergency evacuation of the theatre than a plan in which there are exit doors only at the screen end of the auditorium and a restricted back-to-back row spacing of from 32 to 34 inches. The National Board of Fire Underwriters Building Code permits a greater number of seats from aisle to aisle, as shown in this same diagram (No. 3). The specific conditions under which this design can be used are set forth in the 1943 edition of the National Board of Fire Underwriters suggested code, under Article 13, "Places of Asserribly, Theatres, Motion Picture Theatres, Assembly Halls and Garages." It is stated: "When individual fixed seats are provided or required, no seat shall have more than six seats intervening between it and an aisle; providing that if the seats are fixed chairs with self-raising seats so spaced that when the seats are raised there is an unobstructed space of not less them 18 inches horizontal projection between the rows of seats; and doorways leading directly to exit corridors are provided not more than 5 feet apart along the sides of the auditorium, the number of seats in a row shall not be limited." In Diagram 4, a plan for 400 seats is shown, laid out so as to reduce the objectionable depth of seating indicated in Diagram 1. This is done by placing 7 seats against each side wall and having a section of seats in the center 14 chairs wide. This arrangement conforms to most building codes. It has many disadvantages, however. The aisles are necessarily placed in areas which are otherwise most valuable for viewing positions. The number of seats which come outside of the 60° viewmg angle and afford poor viewing positions are far too many compared to any of the other schemes illustrated. This shape should be avoided for this size of theatre; if local authorities permit. FLOOR %LO?Z% AND 5IGHTLINE5 Unobstructed vision of the projected picture can be assured with various types of floor slopes. Steep inclinations are entirely unnecessary if a proper staggered placing of the chairs is arranged. A minimum of floor slope is always desirable. The slope of the main floor seating can vary from one that slopes downward only toward the screen end, to one that slopes partially downward and then upward. (In some special instances, it would be better to have the longest slope upward toward the screen, with a downward slope for only a few rear rows.) In any case, the amount of slope, up or down, can be limited in so small a theatre to a total of approximately 28 inches // a staggered seating arrangement is used. BETTER THEATRES, JUNE I. 1946 The topography of the ground, or the inclusion of an upper level of seating, will determine the type of floor slope for the main floor seating. A slope downward only towards the screen end is recommended when an upper level of seating is not contemplated and when the natural ground slopes downward toward the proposed picture position is more than approximately 3 feet. Such a slope will place the exit door sills in closest proximity to outside grades, thereby avoiding ramps and steps at exit doors. Where the ground is more or less level, or slopes upward toward the screen end of the building, and where no upper level of seating is contemplated, the main floor slope should be one that is .inclined partially downward and partially upward toward the picture. This again will place exit door sills at desirable levels. If, with this type of natural ground slope, an upper level of seating is contemplated, then the amount of floor sloped upward toward the screen end should be as great as, or slightly greater than, the amount inclined downward toward the picture. This is advisable because it places the picture at a position which is more equally favorable to both the main level and the upper level of seating, and it also makes it possible to use minimum riser heights between seating platforms on the upper level. Only in isolated instances is an upper level of seating to be considered along with a strong upward ground slope (4 feet or more) in a direction toward the screen end. When they do occur, however, the auditorium floor slope should be almost entirely upward toward the picture. The bottom of the projected picture should not be more than 72 inches above the floor at the front row of seats, regardless of the floor slope design. A higher picture position creates too sharp an upward viewing angle for those seated in a number of the front rows. "ARRiyAL POINT OF SIGHT" The rate of floor slope is not constant, but varies according to sightline variation. The eye of any viewer should be on a direct line to the desirable "arrival point of sight" at or near the bottom of the picture (see explanation below of "arrival point of sight"). This line should clear the top of the head of a person seated two rows or more in front. With a properly designed slope, all heads three or more rows in front of the viewer will be cleared if heads two rows ahead are cleared. Explanation of "arrival point of sight." The arrival point of sight may advisedly be directly at the bottom of the projected picture, or slightly above or below this point, subject to the particular row for which sightline clearance is being calculated. For example, in the 22nd row it is desirable to have the arrival point of sight approximately 10 inches below the bottom of the picture, whereas for the 5th row the arrival point of sight can be as much as about 14 inches above the bottom of the picture. In the rows most 1 emote from the picture, the arrival point of sight should come below the picture tc« provide a margin of safety, because obstruction created by a person having an above-average height when seated is more serious than it is in rows close to the pic IS.