Cinematographic annual : 1930 (1930)

254 CINEMATOGRAPHIC ANNUAL quality is properly adjusted with the design efficiency of the lamp; thus there remains a need for effective control in directing the light that the various parts of the set may appear in their desired relative brightnesses and the highlights and shadows be at the command of the lighting director to enable him to obtain the precise effects called for by the action. In a practical study of cinema studio lighting, it is convenient to classify the lighting as general and modeling. The purpose of the general lighting is to provide a ground work illumination which is fairly uniform throughout the set. It not only illuminates the areas that the modeling lights do not serve, but allows control of the shadow density. For the more usual cases, the general lighting does not create noticeable highlights or shadows; this is the function of the modeling lights. Of course, there are frequently instances where equipment normally used for general lighting can be employed to good advantage in creating modeling effects, as in the case of "close-ups." Modeling by means of light is accomplished by the creation of highlights, shadows and contrasts, and equipment for this purpose should be capable of producing high intensities over small areas. For large areas at considerable distances, modeling equipments are often used for general illumination. General Lighting The intensities required for general lighting will vary with the nature of the set, the action, colors of the properties and the type of photography, that is, color or black and white. A study of the general lighting requirements of a variety of sets and of other factors, such as lens speed and film characteristics, shows that the general lighting equipment should be capable of providing 200 to 500 foot-candles at distances of from 6 to 20 feet for black and white photography. Broadside Units Ordinarily, the camera is aimed nearly horizontally and hence the illumination on vertical surfaces is most important. For the smaller sets, much of the action usually occurs over areas from 6 to 12 feet deep and the required light can be provided best by lighting equipment placed either side of the camera. These broadside lighting units ("broadsides") should be capable of providing relatively uniform illumination through horizontal and vertical angles of approximately 60 degres, and the horizontal angle of cut-off should not be greater than 90 degrees in order to keep down the illumination on the side walls of the set and the spill light from striking the camera. It is fortunate that both the horizontal and vertical angles of uniform light spread are approximately the same (60 degrees), as this permits a symmetrical reflector with resultant high utilization of the light.