* A LITTLE BIT OF THEORY - 7

THE EMOTIONAL AND PHYSICAL PROPERTIES OF COLOUR

Colour is one of the most important components of painting. Unfortunately the physics of colour is quite complicated and so is the scientific terminology. Fortunately we don’t have to remember any of it - just be aware of what happens. It’s like grammar - you don’t have to know what a subjunctive is to use it.

So, without going into the physiological processes to explain the impact of colour on the eye, suffice it to say that all colours have physical qualities.

Pure or saturated colours can be identified when a glass prism is used to physically break up a shaft of light into its constituent colours. These pure colours are technically referred to as hues. Their degree of purity is known as tone.

The three primary colours are red, yellow and blue. On a colour wheel they are separated by intermediate colours - which harmonise with each other. Complimentary colours lie opposite each other - and they give a feeling of contrasting.

Theoretically when the three primary colours are mixed together the result is white, and a total absence of colour results in black. Things are not so simple for a painter, and we must use white and black pigments to obtain these effects.

The tonal values of colours are their relative lightness or darkness. For example, on a colour wheel, blue and purple are darker than yellow and orange. In painter’s terms, shades are produced by mixing colours with black pigment and tones result when colours are mixed with white paint.

Because of the physical effect on the human eye, colours are also considered to have a kind of temperature, with reds and yellows being warm and blues and greens are cool. Warm colours have a tendency to advance towards the viewer, whereas cool colours recede.

In addition to these physical features, colours are also imbued with cultural values. In an Anglo Saxon society, white is used at weddings (whereas in some countries it is used at funerals) and black is usually considered appropriate for sombre occasions (but in some parts of the world it is considered a lucky colour).

Now, forget all of the above and just try to remember the most important effects:

Reds and yellows have a warm feeling and seem to advance towards you - cool colours like blues and greens do the opposite – they appear to receed into the background.

In my copy of this late Van Gogh (Peach Blossom in the Crau) I have used reds and yellows in the path in the foreground. Almost everything else in the painting is green or blue - except for the buildings which are ochre and the blossoms which, although essentially white, they do have a touch if pink in pigment. I hope this emphasises their relative importance in the composition.