How to Light a Picture Theatre.

Progress, Volume XV, Issue 1, 1 September 1919, Page 594

How to Light a Picture Theatre.

The old idea that pictures thrown on a screen by a lantern require a completely darkened room to be clearly seen was shown to be incorrect long before the invention of the moving picture French experimenters demonstrated that all that was needed was that'light" from without should not fall directly on the screen itself nor shine into the spectators' eyes. Yet it was some time before the movie-producers realized that their theatres need not be dark. Some are even now too dark for comfort. There is no need for this, since the problems involved have now been completely worked out by illuminating engineers. The requirements and 'their practical fulfilment are both stated clearly in an article in "The Electrical World" (New York, May 17). Says this paper:— "When lighting problems are considered, auditoriums of photoplay theatres present a condition differing somewhat from that presented by the legitimate theatre because sufficient light must be furnished to permit'the audience of the photoplay theatre to find

its way about, yet the distribution of .this light must be such as not to interfere with the picture on the screen. The intensities in different parts of the theatre may be materially different, since the surface most vitally important is the screen! It is usually quite practicable to raise the illumination in the rear or at the entrance if the motion-picture screen itself is properly submerged in darkness. “In this way a person entering is not at first subjected to so low an intensity of illumination as he is after passing down toward the front of the theatre. The minute or two which elapses between the time of entering and the time of reaching an . area of low illumination gives the eye a certain amount of time in which to accustom itself to the lower intensity. “A second requirement of this type of lighting is that the greatest amount of illumination should be thrown upon the horizontal plane, that is, the seats and aisles. It is considered poor practise to throw any amount of light on the side-walls because of the effect of reflection toward the screen. Moreover such

light serves no useful purpose. The third point to be considered is the elimination of sources of light firom the field of vision. In this -category, fall such items as bracket lamps along the side-walls or lamps on either side of the screen, if the units are low enough to catch the eye. Such lamps not only tend to disturb the eye, but they also produce depression of vision and cause a diversion which detracts attention from the picture. '

"As an example of a method by which such lighting can be worked out, an illustration is shown of a lighting installation at E'scanaba, Mich. . . . The lighting is effected solely by means of artificial windows in the ceiling. Above these windows are long boxes approximately 18 inches in height, painted white inside. These boxes act as diffusers, throwing the light through the windows into the auditorium. The type of glass used gives very good diffusion and efficiency. The lamps are arranged on three separate circuits, allowing for the/use cf full intensity, • a secondary intensity, or a very low intensity for photoplay work. The lamps on the circuit which give the lowest intensity have been so graded in size as to furnish a very low value of illumination near the front of the theatre and a higher value, of illumination near the rear. This type .of lighting /directs the greater percentage of light to the seats and aisles, where it is needed." " ' '