MOTION-PICTURE PHOTOGRAPHY 



687 



descent lamps and a third in the case of carbon arcs are in the 340 to 700 van photo- 

 graphic band, the rest being radiant heat in the infrared 700 to 5000 m/x region. ^ 



In respect to factor 2, the spectral characteristics given in Fig. 30 may be modified 

 by filtering at the lamp. For example, in the case of high-intensity arcs, if it is desired 

 to simulate daylight more closely, the excess blue and violet radiation may be held 

 back with light straw-colored or amber filters. Conversely, the tungsten lamp may 

 be brought closer to daylight color balance by means of blue filtering. 



The discussion of factors 3 and 4 entails a description of actual types of lamps used 

 in the studios, prefaced by a further consideration of the two basic methods of light- 

 ing.^ The traditional division, as we have already seen, is between general lighting 



Fig. 31. — Rifle lamp. 



Fig. 32. — Side-arc. 



over the entire set, at an average illumination of 200 to 400 foot-candles, and special- 

 ized lighting by means of concentrated beams, A^ariously known as "modeling," 

 "spot," "personal," and "effect lighting." The latter produce high lights in a scene 

 already illuminated to the foundation intensitj^ of 200 to 400 foot-candles; these high 

 lights may be about 400 to 9000 foot-candles. All these figures are merely estimates 

 since cameramen differ widely in their lighting pecularities, and a "heavy lighter" 

 may habitually work with intensities two times or more as great as a "low-key lighter." 

 Moreover, while the distinction between modeling and general lighting is valid and 

 useful, there is no hard-and-fast division nor is the classification of equipment for one 

 purpose or the other always rigid. While modeling units are normally employed for 

 specific lighting in narrow beams (10 to 20°), most types are capable of being flooded 

 out to angles between 20 and 45°. The angle of demarcation between spotlighting 

 and floodlighting is generally accepted as 20°. 



1 These figures are taken from R. E. J'arnham, Lighting Requirements of the Three-color Techni- 

 color Process, Am. Cinematographer, July, 1936. 



- In this, as in some other portions of this section, principal reliance has been placed on the reports 

 of the Studio Lighting Committee of the Society of Motion Pict\ire Engineers, especially the report 

 published in the January, 1937, issue of J. Soc. Motion Picture En(/rs. 



