The colour wheel conveniently groups the warm and cool colours in opposing arcs facing one another; the greens, blues and purples on one side, which are cool and the yellows, oranges and reds on the other.

Cool colours tend to move away from the viewer, making spaces appear to be larger than they actually are, whilst warm colours tend to do the reverse, moving towards the viewer, making spaces smaller and more ‘cosy’. Rotating the selection around the circle can allow the colour scheme to have contrasts within it by for example selecting blues, greens and yellows, cool colours with contrasting warmth, or oranges, reds and violets, warm colours with contrasting coolness. Contrast can also be obtained by variations of background colour. A patch of colour will appear brighter in a dark background and dimmer in a light one, but a high level of contrast between colours can cause fatigue.

With respect to choosing colours for building materials, there are many criteria governing their selection, relating to cost, economy, availability and preference, always taking into account considerations for performance, strength, resistance to the effects of the weather, lifespan and ease of maintenance and replacement. No matter what technical reasons are used to support selection, their appearance is fundamental and the essential issue is whether or not they will be naturally finished or decorated. The implication is that a naturally finished material such as brick, stone, glass or timber should require little or no attention in the future with respect to its appearance. A naturally finished material will subtly change its appearance through weathering or through general usage but will essentially retain its integrity and its originally selected qualities.

An applied finish or decoration can be periodically refreshed or even altered completely at some time in the future. To a large extent the boundary between the two options in the UK occurs between external and internal conditions. The climate in the UK is such that every effort is now made to eliminate exterior decorative maintenance. The development of plastic coated steel sheet cladding and UPVC window and door frames, and fascias for example has lead to their widespread use on nearly every type of building constructed today. This is not the case in many other countries, where there is a greater sense of colour and flair in the external appearance of their buildings. Traditionally many buildings in this country were rendered and painted, but the onerous task of maintenance has largely made this type of finish redundant.

The possibilities for the use of colour are much greater with modern materials than was the case in the past, offering opportunities to create exciting and stimulating buildings, but equally imposing greater responsibility on those to whom it falls to make the choices.