A study of user preferences for fluorescent lamp colours for daytime and night-time lighting

A field study has been made in eight offices in a new municipal building to determine the fluorescent lamp colours preferred by the staff for supplementing daylight and providing the night-time lighting. Four of the offices were glazed with clear glass and four with tinted 'Anti-sun' glass. Office areas and ceiling heights varied as did the illumination levels in the different offices. It is concluded that for supplementing natural daylight the Daylight (CCT 4300 K) lamp is best on account of its compatibility with daylight and its high luminous efficacy. This lamp was also well accepted for night-time lighting. The White (CCT 3500 K) lamp was in general the second choice.