Exposing colour: Newton's theory through Maxwell's lens

This paper provides an overview of Maxwell’s achievements in the theory of colour. As a matter of fact, Maxwell created inter alia the foundation for quantitative colour measure and for practical colour photography. From his first attempt of colour diagram has evolved the CIE, Commission International d’Eclairage (International Commission on Illumination), model, first published in 1931, which is the most popular system of colour representation in use today and considered the basis of modern colorimetry. Newton’s theory of colour represents a fundamental starting point for Maxwell’s research in the field. In this paper Newton’s influence on Maxwell’s work on colour will be discussed, underlying the aspects that Maxwell accepted and those he refined of Newton’s theory of colour in order to better understand the evolution of his theory. He clarified the difference between optical and pigment mixture of colours and eliminated the arbitrary choice of the number of primary colours. Finally, a brief overview will be provided of Maxwell’s colour mixing experiments, the famous colour top and colour box, that allowed him to determine quantitative expression of colour mixing in form of colorimetric equations.