My forthcoming book on Colours and Colour Vision concerns many different aspects of this subject matter: how colours arise, how one might see and experience them, and how they have been used and talked about. When writing this book, my first source of inspiration was my own visual system: I belong to the rather large minority with an inherited red-green blindness. It has often astonished me that most people know so little about what this sensory constitution means, in spite of the fact that, in Western Europe, it concerns more than 4% of the total population. Thus, I started my writing-enterprise as a book about colour blindness, but the project gradually expanded to become a more general survey of matters concerning colour. The description includes an account of the physiological mechanisms of colours and colour vision in man and animals, which comes natural to me because I worked for many years with neurophysiological research (albeit on other subjects than colour vision).
Colours often give us a very direct and immediate kind of sensory experience and one might therefore be inclined to think that the nature of the phenomenon is simple and straight-forward. This is, however, not the case: the physiology of colour vision is a highly complicated and multi-dimensional subject matter. For many people, colours are an important source of enjoyment in everyday life, in nature, in various expressions of art and culture (true also for red-green blind persons). Publications about colours are often mainly dealing with their various aesthetic qualities. In 1819, Keats published his very long poem “Lamia“, which includes a few famous lines suggesting that the rainbow might loose its colourful beauty if one knows too much about it:
Philosophy will clip an Angel’s wings,
Conquer all mysteries by rule and line,
Empty the haunted air, and gnomed mine
Unweave a rainbow.
However, it might equally well be argued that the unweaving of a rainbow does not make its colours and beauty less impressive but rather the opposite: the more one knows about a subject the more interesting and captivating it usually becomes. According to some interpretations of Keats’ poem, the author himself and his contemporary colleagues might even have agreed on this point, provided that one does not lose one’s sense of wonder when confronted with the many complexities of human perceptions and the natural world.
Colours are not only complex with regard to their physical, physiological and psychological mechanisms, but they also offer an interesting variety of philosophical and linguistic problems. The seeing of colours is a very personal kind of conscious experience; perceived colours cannot be well described and defined for somebody who has never seen them. For such reasons, philosophers have often found colours to be problematic kinds of concepts. When comparing different languages, including non-written ones used by relatively small groups of people, huge variations are found with regard to the linguistic colour analysis. Colour vision is, due to the variety of problems concerned, a truly colourful subject matter.