Lightness and Brightness and Other Confusions
Lightness and Brightness and Other Confusions
Lightness and Brightness and Other Confusions
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Discussion<br />
From all of this one may gather that it is very easy indeed to be misunderstood<br />
when talking about the variables of colour. Perhaps the greatest stumbling<br />
block is using the terms without reference to their context <strong>and</strong> mode of<br />
appearance: related colours are a different kettle of fish from non-related<br />
colours; so are luminous colours in relation to non-luminous ones (lights in<br />
relation to surfaces). Of course, one could argue that in the real world colours<br />
are always related. Even a single lamp in darkness is related to the surrounding<br />
darkness <strong>and</strong> all colours are related to what has been seen before. The<br />
strength or vividness of their perceived colour, whatever name this attribute<br />
is given, seems a natural <strong>and</strong> easily underst<strong>and</strong>able feature of the appearance<br />
of objects <strong>and</strong> surfaces in natural scenes. It is perhaps only when one tries to<br />
isolate visual features from their mode of appearance <strong>and</strong> from each other<br />
that things become complicated (even though the objective was perhaps the<br />
opposite). Different modes of appearance of colour (surface, film, volume,<br />
glow, lustre, etc.) 84 seem to require different definitions of colour strength:<br />
the intensity of redness in red wine is a very different thing from the redness<br />
of an apple or the vividness of a sunset. Their “colourfulness” is judged<br />
against different starting (<strong>and</strong> ending) points <strong>and</strong> along different scales.<br />
These differences in the modes of appearance are reflected in the geometry<br />
<strong>and</strong> mathematics of various colour systems <strong>and</strong> colour models, but their<br />
natural contexts are lost in the abstractions of the definitions.<br />
<br />
For definitions of modes of appearance of colour see Katz 2002.<br />
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