The aim of the investigations described in this paper is to study the influence of the colour of the light on discomfort glare in street lighting. This necessary observations were carried out in a laboratory model using light from sodium lamps, mercury lamps with fluorescent bulbs, tubular fluorescent lamps, incandescent lamps and incandescent with yellow colour filters as used for motor-car headlighting in some countries. The observers showed a definite preference, from the point of view of limitation of glare, for the "warmer" coloured light-sources. The luminance of the fittings which should not be exceeded is a certain degree of comfort is to be maintained, was found to be approximately proportional to the square root of the road luminance. The results obtained during these investigations differ from those published carlier. These differences can partly be ascribed to divergences in the measuring techniques used by the various investigators.
Abstract