On the calculation and measurement of mean room surface exitance

Cuttle has proposed mean room surface exitance as a metric for use within interior lighting design. Two reported barriers to its use are: a lack of available software to calculate the metric and the tedious and cumbersome nature of recording its values in the field using current equipment and methodologies. This paper presents a method for facilitating the calculation of mean room surface exitance using readily available freeware, namely Radiance, and also presents a methodology that utilises high dynamic range imaging as a pragmatic alternative for field measurement.