Richardson's handbook of projection (1930)

1236 HANDBOOK OF PROJECTION FOR common locations, but it is of much greater importance. .This will be treated later. DIMENSIONS (size of room).— The size of the room may vary rather widely, according to the amount of equipment it is intended to install, but in width the wise exhibitor will make ample allowance for possible additional equipment. That is just as important as it is to install wiring having capacity sufficiently in excess of immediate needs in order to take care of demands which may be made in the future. It is an expensive thing to rebuild the room, or to tear out the wiring to install larger wires, but at the time of construction neither a bit of added space or somewhat larger wires present any very serious additional outlay. In the matter of front to back depth there must be sufficient space to leave at least a thirty-six (36) inch passageway clear of everything between the lamphouse controls and whatever may be against the real wall. That amount of space is imperatively necessary to a good condition. The necessary depth may be ascertained by the architect by taking the over-all projector length of the modern projector, setting in horizontal position at sixtythree inches, adding one foot to that measurement, or eighteen inches if the projection angle will be a heavy one, and thirty-six inches plus the depth of whatever equipment it may be intended to place back of the projectors against the rear wall. In fact, it is best to allow three feet for that latter, whether there is present intent to install anything there or not, which would make a total of five feet three inches plus six feet equals eleven feet three inches as the minimum front to back depth. In the matter of ceiling, seven and one-half feet should