colour and light
Sir Isaac Newton’s experiments with prisms, where white light passing through a prism emerges in a spectrum of colours like a rainbow led him to conclude that “Colours in the Object are nothing but a Disposition to reflect this or that sort of Rays more copiously than the rest.” In other words, light is composed of different rays (we might now say different frequencies), a given surface reflects certain rays and absorbs others. If it reflects low frequencies and absorbs high, then its colour will be at the red end of the spectrum whereas if it reflects high frequencies and absorbs low then it will be towards the blue end of the spectrum. However, a study of simultaneous colour contrasts shows that the “same colour” will look very different depending on its context. So “pattern of reflectance = colour of surface” is not the whole story, there is the ‘subjective’ side of colour construction to take into account.
Donald D Hoffman, in his book Visual Intelligence shows just how complex a process this is, and suggests some of the rules we use to construct the colours we see. I borrowed one of his experiments/demonstrations (which he credits to Christoph Redies and Lothar Spillmann) for my painting Glow Grid, where coloured discs are constructed by the viewer:
and more recently I have been playing with colour mixing and wondering about how much of this takes place on the canvas (out there) and how much takes place optically (in here).
In the New Testament (of all places) we read that “the light of the body is the eye” emphasising not the objective (out there) source of light and colour (as perhaps J.M.W. Turner did when he said “the Sun is God”) but the subjective “in here” construction of it.