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.

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Selections From Dismissing God by Donald D. Hoffman (via Paying Attention To The Sky)

I am thoroughly enjoying the writing of Donald D. Hoffman

you could say I am a big fan

He writes about visual perception and how we construct the world in which we live. No room for gods in this world view?

Donald D. Hoffman is a Professor in the Department of Cognitive Science, University of California Irvine, California. If you are like me, you may be a little tired of the Steven Pinker neuroscientists and their broad claims at having discovered the Soul or God in the human brain. Dr. Hoffman makes a clear case here as to what neuroscience knows and doesn’t know. Debates between theists and atheists often hinge, naturally enough, on advances in co … Read More

via Paying Attention To The Sky