Light is fundamental to life. At its simplest level, light enables us to enjoy the world around us and carry out a myriad of visual tasks. It can create a psychological mood of delight or melancholy, or one that is stimulating or soporific. Lighting may affect our performance. It is also believed to affect our health, although the link is not yet well established. However, it is felt that by providing a visual amenity, people's feeling of 'wellbeing' will be enhanced and their performance increased.