Colour plays an extremely important role in our everyday lives. Why this should be so has exercised the minds of some of our greatest philosophers for many centuries.1 ^,2 What is colour, what role does it play in nature, and in our social and intellectual environment? Even today the answers to these questions are far from known and arguments over the psychological and social impact of colour continue to rage.3 ^,4 However, ever since Newton recognised the relationship between light and colour in the late 17th century, our understanding of the hard science behind colour and its myriad of applications has been increasing gradually, until it has reached today s level of sophistication.5 ^,6 Rather interestingly, a marriage between our understanding of the physics and chemistry of colour and their utilisation in both art and technology has become a topic of growing interest to many authors.7 ^,8 ^,9

This book is concerned with the technological applications of colour chemistry and there is no intention in this introduction to cover the theoretical aspects of the topic. Specific aspects of colour theory are covered as needed within the main body of the text. For those requiring a more detailed treatment of the theoretical aspects of colour physics excellent texts are available,5 ^,6 whilst they are summarised in very readable forms in others of a more general nature.8 ^,9

There are many ways in which colour can be caused to arise both by chemical and physical forces,...