260 HANDBOOK OF PHOTOGRAPHY 



data published regarding the use of exposure meters for special applications. The 

 majority of these data can be summarized as follows: 



1. Measure the brightness of the principal area in the scene, the face for portraiture 

 work, the principal building if taking a street scene, etc. Convert this reading into 

 exposure values according to the instructions furnished with the meter. If the 

 particular scene is extremely contrasty and details in the shadow and high-light areas 

 are desired, then measurements should be taken of these two areas and a geometric 

 mean value of exposure chosen. 



2. For highly specialized work where special lighting and certain types of pictures 

 are required, it may be necessary to develop a special technique in reading and inter- 

 preting the meter readings into photographic exposure. For example, on a certain 

 type of setup it may be noticed that either over- or underexposure is consistently 

 obtained. This may be due to any number of things such as the quality of the Ught 

 being considerably different than that used in determining the film-speed value, camera 

 calibration or meter calibration may be incorrect, etc., but, by considering the exposure 

 meter, not as an infallible tool, but as a useful practical tool, corrections can be 

 artificially made by altering the rated film speed value to correct for consistent over- 

 or underexposure. 



Bibliography 



GooD^v^N, W. N., Jr.: The Photronic Photographic Exposure Meter, J . Soc. Motion Picture Engrs., 20, 

 95 (1933). 



Lakst, M., and B. Rubin: A Practical Method and Photometer for Controlling Exposures in Photog- 

 raphy, J. Soc. Motion Picture Engrs., 21, 155 (1933). 



Harrison, G. B.: Photoelectric Exposure Meters, Phot. J., 74, 169 (1934). 



McKay, H. C: Making the Most of Exposure, Am. Ann. Phot., 1935. 



Goodwin, W. N., Jr.: Weston Speed Ratings and How Obtained, Am. Phot., 32, 538 (1938). 



