OVERVIEW

We only have to open our eyes and look around to observe how important a part colour plays in our everyday lives. Colour influences our moods and emotions and generally enhances the way in which we enjoy our surroundings. Our experience of colour emanates from a rich diversity of sources, both natural and synthetic. Natural colours are all around us, in the earth, the sky, the sea, animals and birds and in the vegetation, for example in the trees, leaves, grass and flowers. Colour is an important aspect in our enjoyment of the food we eat. In fact, we frequently judge the quality of meat products, fruit and vegetables by the richness of their colour. In addition, there is a myriad of examples of synthetic colours, products of the chemical manufacturing industry, which we tend to take so much for granted these days. These colours commonly serve a purely decorative or aesthetic purpose, but in some cases specific colours may be used to convey vital information, for example in traffic lights and colour-coded electrical cables. Synthetic colours are used in the clothes we wear, in paints, plastic articles, in a wide range of multicoloured printed material such as posters, magazines and newspapers, in photographs, cosmetics, ceramics, and on television and film. Colour is introduced into these materials using substances known as dyes and pigments. The essential difference between these two types of colorants is that dyes are soluble coloured compounds which are applied mainly to textile materials from solution...