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PRIME: PSYCHOLOGY,
continued
While
colour vision
may be defined as the ability of the eye to recognise
different frequencies in the visible spectrum, as colours,
it is much more than just this. We do not see colours
simply according to wavelength of light. One should
not forget that colours are constructs
of the brain, rather than physical features of objects
or their surface. Colour constructs
remain more or less stable, and objects remain recognisable,
in spite of the continuously changing illumination in
which they are seen, a phenomenon known as colour constancy.
A television camera has a special filter to reduce the
abundance of blue
found in daylight. If one looks at a colour photograph
taken in both fluorescent (green light)
and/or tungsten (amber light),
one however, may not recall from memory, the disparity
of coloration thus documented on the photograph. Richard
Gregory writes with regard to colour
constancy:
"
The eye tends to accept as white not a particular mixture
of colours, but rather the general illumination whatever
this may be. Thus we see a car's headlamps as white
while on a country drive; but in town where there are
bright white lights for comparison, they look quite
yellow. The same is so for candlelight compared with
daylight. This means that the reference for what is
taken as white can shift. Expectation, or knowledge,
of the normal colour of objects is important: oranges
and lemons take on a richer colour when they are recognised;
but this is certainly not the whole story. " (footnote
10.)
| Humans
appear to dynamically re-adjust and maintain
constant colour values, naturally, through a
reconstruction; within the optical
processing centre of the brain. Whilst this
might be helpful to the artist, working in changing
light, an ability to somehow over-ride the function,
may also be an asset; especially, when painting
from a variety of light sources, of consistent,
but differing frequency band-widths; particularly,
for example, when observing warm and cold shadows,
vis-a-vis the warm and cold highlights,
in an egg, or a person‘s flesh. |
|
Lit
shadows |
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