Gavin Evans - The Story of Colour: An Exploration of the Hidden Messages of the Spectrum

First published in Great Britain in 2017 by

Michael OMara Books Limited

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Tremadoc Road

London SW4 7NQ

Copyright Gavin Evans 2017

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A CIP catalogue record for this book is available from the British Library.

ISBN: 978-1-78243-690-4 in hardback print format

ISBN: 978-1-78243-691-1 in ebook format

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Cover design by Ana Bjezancevic

Every reasonable effort has been made to acknowledge all copyright holders. Any errors or omissions that may have occurred are inadvertent, and anyone with any copyright queries is invited to write to the publisher, so that a full acknowledgement may be included in subsequent editions of the work.

To my daughters Tessa and Caitlin: it would be an awful clich to say you put colour in my life, but Ill say it anyway.

CONTENTS

I f pupils were concentrating at school they might have learnt the mnemonic Roy G Biv, one way of teaching children the usual order of colours of the rainbow red, orange, yellow, green, blue, indigo, violet just as some British children learn the alternative Richard of York gave battle in vain. In India pupils learn VIBGYOR, which is the reverse order of Roy G Biv. Either way round, no purple and most definitely no pink.

And yet, are red, orange, yellow, green, blue, indigo and violet really the correct colours of the rainbow? Well, yes, and one can add to the list or subtract, as long as one doesnt throw in grey or gold or brown, or pink, for that matter. It all depends on where one lives, or when one lived, because the received colours of the rainbow have changed according to culture and over time.

Let us go back to the man who invented what became Roy G Biv: perhaps the most remarkable scientist of them all, Isaac Newton. Along with his discoveries on the laws of planetary motion and of gravity, and his co-discovery of calculus and his huge contribution to developing the scientific method, he was obsessed with light and colour. This prompted one of his most famous experiments (in his rooms, during the Great Plague, when the university was closed). Using a partition board with a pinhole in it and a glass prism, he observed how white light can be broken into the colours of the rainbow.

As Newton explained it: In a very dark chamber, at a round hole, about one-third part of an inch broad, made in the shut of a window, I placed a glass prism, whereby the beam of the suns light, which came in that hole, might be refracted upwards toward the opposite wall the chamber, and there form a coloured image of the sun.

He showed that white light is the combination of the full colour spectrum. In his book Opticks (1704), he explained how these colours comprise light rays that bend, or refract, at different angles when passing through a prism, so the colours separate. The ray that bends the most is violet, with the shortest wavelength, and the least is red, with the longest wavelength. In the middle is green. Crucially, he reversed the experiment too, demonstrating that the spectrum of colours can be reassembled into white light.

A century on, in a book titled Theory of Colour, the great German thinker Johann von Goethe described Newtons idea that white light was a combination of all the colours as an absurdity and he moaned about people parroting Newtons idea in opposition to the evidence of their senses. What Newton understood, and Goethe failed to grasp, was the difference between the colours of the paintbox and those of light. Mix the pigments of the artists palette together and one gets a very dirty grey-brown. But when considering light, it all changes. Spin a colour wheel fast enough and it will appear white.