Chromatic effect on apparent brightness in interior spaces I: Introduction and colour gamut models

A series of experiments were conducted to study the effect of lamp spectrum upon the perception of lighting in interior spaces. Previous models of brightness perception were analysed to see whether they could explain the experimental results, of which three were adapted to fit the experimental data and are discussed in this series of papers. The experimental results to which the proposed models were fitted are first summarised. The results are then modelled using a colour gamut defined as the surface area of a regular cone in CIE 1976 uniform chromaticity space, a new colour gamut which is sensitive to both the colour rendering and colour appearance of a spectrum. Cone surface area is found to have higher correlation with the experimental data than gamut area.