All colors can be defined using three simple indexes; hue, saturation and value.

1. Their color name as in red, blue, green or yellow. This is called their ' hue '.

Here are some examples of hues:

  Cadmium red
  Ceruleum blue
  Ultramarine blue
  Lemon yellow
  Yellow ochre

Most people just know them as red, yellow or blue. Do not be confused by trade names such as 'Rocking chair red' or 'Hooker's canary yellow.'

Try and remember the names of the common artists colors like those above but try and keep it simple. In the art supply shop ask for a color chart.

2. A colors strength or intensity. How blue is that blue or how red is that red? This is called their 'saturation' and can be high or low.

Still it is a misleading term. 'Midnight, and the artist Giorgione was still in the bar and totally saturated.' In this sense saturation most likley meant 'a lot of wine was absorbed' (Giorgione died young after wounds received fighting).

When a particular chemical absorbs all the wavelengths of light from the spectrum except one, say red (which it reflects in total and which you see), then that red would be at its highest level of saturation If however, a little of the red light was absorbed, then the resulting saturation would be less (a duller red).

In a previous lesson I explained how short wave-length (blue) light was intercepted by the earth's atmosphere at sunset. The saturation of the perceived red would depend on how many of the long wave-lengths penetrated the mist. In that instance the greater the number the higher would be the red saturation index

Computers allow you to select a color and increase or decrease its saturation. Below are some examples:

INDEX 0-240

080 120 200 240

3. A color's brightness or darkness.

The blackest are numbered (1) and the whitest or lightest (10). This is called their 'value' and is measured on a grey scale from 1-10

Of all the indexes this is probably the most significant to a painter. Before anything else, the values in a painting must be correct.

It has long been known that colors (including grey itself) of equal value can be combined for a pleasing effect, but it is the perfect pitch of the highlights or darks that caress the eye. The master artists of times past studied values before anything else, and their skill of estimating the exact value of a color to within 1:40 of the scale was not unusual. I find it often helps to squint the eyes to decide on a value.

Squint at some colors with their grey scale(value) equivalents above and watch them merge.

STUDENT ACTIVITY: On your computer all colors have values of between 1 and 100. It can be found on the 'HSV' color index where the 'V' stands for value. Find all the 'values' of the hues in the table above using your computer. Allow 40min for all.

A note on complementary colors. I often call these 'opposite' colors as they lodge exactly opposite each other on the color wheel (green and red or yellow and purple). When mixed together they produce a grey. When placed side by side, in spots or short brush strokes, they give an impressionistic effect of grey at a distance and of vibrating color up close.

A juxtaposition of large even areas of 'opposite' colors is most uncomfortable to the eye. This fetish has gained some popularity with certain two dimensional artists.

Next ... Colors of the mind and muddy waters.

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