Technical > Colour

If you want to find out a little bit about colours, one of the first places to look is probably X-Rite, manufacturers of Colorimeters and Photospectrometers for well over a decade.

X-Rite have published some excellent information, which we've been bold enough to pass on to you here!!!

Because colour is perceived by the human eye, which is subject to wide variations, no two people see exactly the same thing. Hence, in order to objectively classify colour, it must be measured in some form which allows a numerical expression of each shade and combination of colours.

Identifying colours is achieved based on three characteristics - Hue, Value and Chroma.

Hue is the perceived colour of an object. For example, an object is "red", "green", "blue", "orange", etc. Take a look at Figure 1 (right) to see what I mean.

Value may be described as the "lightness" of a colour - compare a tomato with a radish and you'll see that the radish appears darker than the tomato. In Figure 2 below right, Value is shown on the vertical axis, from white to black.

Finally, Chroma describes the vividness or dullness of a colour. In other words, Chroma indicates how close the colour is to its pure hue or to grey. Going back to the tomato and the radish, the red of the tomato is more vivid than that of the radish, which is quite dull. In Figure 2, Chroma changes on the horizontal plane, with the colours in the centre being dull, but becoming vivid, or "saturate", as they move towards the edge.