The effect of changes in quality of illumination upon visual perception

Abstract

The experiment is an outgrowth of an industrial investigation involving the use of standard Mazda (white-yellow tinge) and C2 Mazda (blue-daylight) lamps in removing dark hairs and foreign material from a white woven flannel. From 1 to 7 gray threads on pieces of white flannel were presented in a tachistoscope under standard Mazda and mercury lamps of 18 foot-candles illumination and daylight Mazda of 18 and 8 foot-candles illumination. The results (based on six students) indicate that blue daylight C2 Mazda lamp (8 foot-candles) gives the smallest limens and is most efficient. Increased attention and greater visual sensitivity for short waves in twilight or dark-adapted vision are two important factors considered in connection with the results. The findings of this experiment in regard to reduced intensity of illumination are not in agreement with previous industrial experiments and may not be applicable to the industrial situation, since the records were obtained under short experimental periods and general artificial illumination. (PsycInfo Database Record (c) 2025 APA, all rights reserved)