Samenvatting
Measurements are made about visual acuity, speed of recognizing of a single object, and speed of reading, by sodiumlight and white light, especially at the levels of brightness which are of importance in the practice of street lighting. The visual acuity is measured as a function of the brightness of object and background. The visual task was the recognizing of small circles and squares on a contrasting background. The results are compared with other measurements.