Performance and comfort in the presence of veiling reflections

Abstract

Experiments on performance and comfort at visual tasks similar to reading and writing under lighting conditions of veiling reflections show the necessity of basing the lighting design for offices and similar working places on criteria of performance as well as on those of comfort and give rise to doubt as to whether a single relationship between contrast sensitivity and adaptation luminance as mentioned in CIE publication 19 is universally valid. For good visual performance convenient values of average luminance and contrast are required; visual comfort requires a limit to be set to the ratio of luminaire luminance to task illuminance. For normal office work this ratio should be kept smaller than 7 cd/m2/lux.