Lightness and Brightness and Other Confusions
Lightness and Brightness and Other Confusions
Lightness and Brightness and Other Confusions
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<strong>and</strong> will use the specific terms only when referring to their specific definitions.<br />
Why so many different words for what at first sight seems the same thing?<br />
One reason is that chromatic intensity of colour can be defined in several<br />
ways. Another reason is that examining non-related colours (as aperture<br />
colours or isolated lights amid darkness) is very different from examining<br />
them in relation to each other. (Billmayer & Saltzman 1981, p 187). Yet another<br />
reason arises from the tradition of conceptualising the attributes colour<br />
as a three-dimensional space. There are many different ways of mapping<br />
colours in three-dimensional models. They all yield different mathematics for<br />
defining the attributes of colour, <strong>and</strong> the different terms for the vividness of a<br />
colour refer to different mathematical relationships of colours within the<br />
abstract models. But there is also a more fundamental reason for so many<br />
different terms <strong>and</strong> definitions of fullness or vibrancy of colour. The concept<br />
gains different meanings depending on whether the viewpoint is physical or<br />
perceptual.<br />
Painters will know that colours can be made less vivid by at least four different<br />
means: by mixing a pure hue with white, which is called tinting, by mixing<br />
it with black, called shading, <strong>and</strong> by mixing the hue with grey, called toning.<br />
In addition, mixing a colour with one of an opposite hue, for example a red<br />
with a green or a yellow with a violet, will lessen the vividness of the colour,<br />
yielding darkish tones or shades of a more neutral appearance. This experience<br />
of controlling the vividness of colours by physically mixing pigments is a<br />
central starting point for much of the concepts <strong>and</strong> terminology concerning<br />
vividness.<br />
Chroma<br />
Chroma (from the Greek word khroma, colour) is given in the Concise Oxford<br />
Dictionary simply as “purity or intensity of colour”, but chroma is not a word<br />
that is in general use. The equivalent lay term in English is brightness, brilliance,<br />
depth, vividness, etc. Depending on the context, such words as muted,<br />
pale, pastel, garish, vibrant, dazzling etc. are also used to describe various<br />
degrees of chroma or chromatic strength. Chroma is an attribute of the Munsell<br />
colour system, which is why it is widely used among colour scientists <strong>and</strong><br />
educators in the USA <strong>and</strong> other countries where the Munsell system has left<br />
its imprint on the colour language.<br />
In the Munsell system colours of equal value (lightness) are placed on the<br />
same horizontal plane. As in most systems, the chroma of a hue in Munsell<br />
increases outwards on a straight horizontal axis starting from the achromatic<br />
centre, but unlike many other saturation-scales, the Munsell chroma-scale of<br />
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