A new direction for general lighting practice

The currently accepted notion that the basic purpose of general lighting practice is to enable performance of visual tasks is examined and found to be lacking in substance. It is proposed that the purpose of lighting should be redefined in terms of the visual experience of illuminated surroundings, and two criteria are proposed for this purpose, both of which represent significant departures from conventional practice. The first assesses the adequacy of illumination for an activity in terms of the density of reflected light from surrounding room surfaces and the second is concerned with how the luminaire luminous flux is directed onto selected target surfaces. Taken together, these criteria offer a quite new approach for designing lighting installations for general practice.