Value of higher intensities of illumination

During the past year, Dr. M. Luckiesh of the Nela Research Laboratories has been investigating the effects of higher intensities of illumination on the speed of reading, and has found a definite increase of “speed of vision” as the illumination intensities increased. For ordinary reading matter (black print on white paper) the speed of reading increased 15 per cent when the illumination increased from 4 to 16 foot-candles. For black print on gray paper, the increase in speed was 50 per cent when the illumination intensity increased from 4 to 16 foot-candles. These data show the value of increasing the intensity of illumination and the results can safely be extended to cover many other visual processes in factory, office or home.