Colour perception: colour interaction

We often think of colour as existing outside us but its ultimate experience resides in our brain and when seen in the context of different coloured backgrounds our perception can play tricks.

Colour is often considered and measured as a physical entity, but its actual experience is first detected by the eye before being 'seen' in the brain. The impact of our own colour perception can sometimes radically alter the appearance of colour. For instance, the difference between physical colour and its perception is demonstrated here. On the right half of the diagram, a light grey rectangle [A] seen against a light background appears the same as the darker grey rectangle [B] below it which is shown against a black background. The difference between A and B is apparent when they are both seen against the uniform grey background on the left half of the diagram. We have, therefore, two different colour stimuli resulting in the perception of a single 'colour' in different contexts.

The visual modification of a hue by its relationship with another can also be demonstrated in full colour.

The extraordinary dynamic of colour interaction is illustrated in this diagram. Here, although existing as precisely the same hue, a Poppy Red accent colour on the inner shape appears to be significantly much more intense in its redness when in relationship to Solent Blue compared with its subdued appearance on a background of Golden Clow. Depending upon the brilliance of the colours that are used, these ever-changing and interacting colour relationships - to a greater or lesser degree - are always present in the design of colour schemes.

Colour perception experiments demonstrate that there is a distinct relationship between hue and shape.

Studies by Wassily Kandinsky at the Bauhaus in Weimar, Germany, and later research in America by Faber Birren agree that there is an established and psychological connection between hue and the geometry of basic shapes. For example, a circle is blue, a square, red, and a triangle, yellow, etc.

Darker coloured shapes appear smaller, heavier and more distant when compared with a similar shape of a lighter colour.

Other experiments in colour perception also demonstrate how colour can modify our understanding of shape and form. Compare the two elevations by viewing them at arms length. The darker coloured building looks smaller than the lighter-coloured one. Dark colours such as Vandyke Brown reduce apparent size; lighter colours such as Poppy Red increase it. The darker coloured building also looks heavier than the lighter-coloured one. The position of the darker elevation above the lighter one makes the illustration appear top-heavy - an effect that, if used in practice, can disrupt the appearance of a building. Finally, look at the perspective effect created by the two elevations. Clearly, the lower elevation looks nearer than the one above. The bright colour appears to advance towards the viewer - an effect often used in building design to highlight important details.