CH. XII] DARKENING THE PROJECTION ROOM 443 



The indirect or concealed light sources which have been recently 

 developed answer all the requirements for suitably lighting a mov- 

 ing picture theater or, indeed, any other place where a soft light is 

 required and the light should not shine directly in the eyes of the 

 spectators (fig. 237 A, B, C). 



It is also an advantage to have the screen in a kind of alcove i to 

 2 meters (3-6 ft.) deep and the walls on the sides, the floor and the 

 ceiling dark brown or dark red or olive to absorb any light reflected 

 upon 'them (6o6a). 



For exhibitions, it also adds brilliancy to the picture to have a 

 black border around the screen. It gives also the effect of a framed 

 picture. 



With such an arrangement of the lights in a suitably tinted room, 

 no light will reach the screen directly to destroy the contrast and 

 render the image vague. There can be sufficient diffused light in 

 the room to enable one on entering to see the aisles and seats, and 

 go about without stumbling. In a short time twilight vision will 

 be established and it will then be possible to read or to take notes. 



607. Red lights near all exits. Fire escapes. In public 

 halls, and especially in moving picture theaters, it is an advantage, 

 and often a requirement in city regulations, to have red lights near 

 every exit so that the audience can see exactly where it is possible 

 to get out of the hall. 



The manager of every public hall should look to it every day that 

 the fire escapes are in working order and before every exhibition 

 that the doors or gates to the fire escapes are unlocked and easily 

 opened. 



608. Relative darkness of the room for different kinds of 

 projection. The amount of diffuse light permissible in the pro- 



606a. While it is a great help to have a screen in a dark alcove, still the 

 general light of the room, although none extends directly upon the screen, 

 tends, if too great, to make the image less brilliant and definite. Every one 

 who has studied astronomy at all with a telescope knows full well how the 

 defmiteness of the image of a nebula or dim star cluster diminishes when the 

 moon rises and floods the heavens with its diffuse light. One can also see the 

 effect of too much diffused light by observing a lighted clock face on a dark 

 night, and the same face with the same light shining from it on a moonlight 

 night or early in the evening twilight before complete darkness. 



