An investigation into the relationship between luminance and brightness of strongly chromatic light sources

Current research literature indicates that strongly coloured light is perceived as being brighter than white light of the same photometric luminance and that current photometric units and methods may be inappropriate for measuring strongly coloured light. A series of simple experiments were undertaken using red, green and blue coloured light to attempt to provide some indication of the possible functionality of coloured light under certain conditions. From analysis of the results obtained, it was concluded that observers performed either better under the red light or equally well under the red or green lights. Performance under the blue light was clearly inferior. Furthermore, subjective assessments did not mirror the performance results. This finding appears to support claims that the concept of luminance does not adequately describe the perception of brightness of strongly coloured light. Finally, lighting equipment that is calibrated to the luminance of white light is wholly unsuitable for the measurem...