Investigation of complementary colour harmony in CIELAB colour space

This study is concerned with one aspect of colour harmony, the complementary relationships between colours. The relationships are most usually represented in colour wheels or hue circles such that opposite colours are assumed to be complementary. However, there is a lack of consistency if different colour wheels are compared. The primary focus of this work is to determine for each hue the optimal complementary hue using psychophysical experiments. The aim is to be able to define the complementary relationships between hues and ultimately to be able to produce a colour wheel that is specifically designed to represent these relationships. Experiments were conducted to ascertain the complementary relationships between hues. The null hypothesis was that opposite colours in CIELAB space would be optimally complementary, producing a maximal colour contrast. However, the experimental data showed systematic deviations from this hypothesis around the colour wheel. The results suggest that opposite relationships in CIELAB colour space do not accurately predict for complementary relationships. Of course, there are many different colour spaces from which we could attempt to predict complementary relationships. The results also indicated a curious asymmetry that merits further study.