EXPOSURE AND EXPOSURE DEVICES 



243 



Table XIX. — Basic Exposure for Color Photography with Photoflood Lamps 



(Weston Ratings — 4 to 8) 



Table XIX is based on the following conditions: 



1. Film Speed. — Suitable for color film having a tungsten rating of Weston 4 to 8, sudi as Dufaycolor 

 or Kodachrome film. For films having other speeds, the shutter speed is inversely proportional to the 

 Weston speed rating. 



2. Apertures. — Table XIX gives the exposure for 10 apertures. Conversion may be made for other 

 apertures by the method given by Eq. (23). 



3. Lamps. — Exposures are given for photoflood lamps operation at 33.5 lumens per watt in polished 

 metal reflectors. If white paper reflectors are used, multiply the exposure time by 2; if no reflectors are 

 used, multiply exposure time by 4. 



It is assumed that only one lamp is used. If n lamps are used, all the same distance from the 

 subject, divide the shutter speed by n for proper exposure. 



