Appearance of lit environment and its relevance in lighting design: Experimental study

Abstract

The purpose of this project was to examine the relationship between a subjective response to a lit environment and its luminance distribution as a contribution to improving lighting design. The study was made using a full-scale mock-up conference room lit in 18 different ways. Observer subjective assessments were examined using factor analysis and this identified two main factors: 'visual interest' and 'visual lightness'. The experiment showed that these two factors could respectively be described by the luminance contrast and the average luminance within a horizontal band 40° wide and centred at normal eye height. The results suggest minimum values for these two parameters which are likely to be necessary for a lit environment to appear both 'interesting' and 'light'.