A definition of global hue contrast in artworks

In the composition, analysis and evaluation of artworks, an understanding of colour is of high importance. Colour is commonly understood in terms of its perceptual components: hue, saturation and lightness. Of these, it is within the hue values of an artwork that many of their high-level aesthetic dimensions are found and it is through the global contrast of hue by which these dimensions are best expressed. However, there is currently no way to computationally define global hue contrast and it is this gap in knowledge that our work addresses. Here we quantify global hue contrast as two values: hue variety and hue antagonism. This definition was derived from Johannes Itten's work on colour contrast. Using our approach the hue contrast of a single image can be expressed as a single point in a plot. For this reason the approach is particularly suitable for the comparative analysis of groups of artworks, such as those by two or more artists or an artist at different times in their career. We describe two case studies both employing our proposed approach and the results agree with manual observations. We also include a user study the results of which further supports our proposed approach.