Qualitative Colour Nomenclature.
SIMPLE COLOURS.
The vision can separate six monochromatic colours from a beam of white
light, therefore in practical work six must be dealt with, no matter
how they may be theoretically accounted for. They naturally take the
accepted spectrum names and symbols already in use. To these are added
two other terms, Bk. to signify black, and L. for light; these terms
deal with the brightness, or dinginess, of a colour.
Simple Terms. Symbols.
Red R
Orange O
Yellow Y
Green G
Blue B
Violet V
Black Bk
White L
COMPLEX COLOURS.
The order of the association of simple colours to form complex, is
governed by two factors. The first is a physiological limitation of
the vision, which is unable to simultaneously distinguish more than two
colours, in the same beam of light, this limits the most complex colour
to two colour names. The second limitation is one of association, based
on the experimental fact, that the particular two must be adjacent in
their spectrum order, spectrum red and violet being considered adjacent
for this purpose. Under these conditions, any given colour must be
either a monochrome, or a bichrome, and all complex colours must be
bichromes. Therefore the only possible combinations are as follows:--
Red and Orange
Orange " Yellow
Yellow " Blue
Blue " Green
Green " Violet
Violet " Red
The classified order of associating symbols for describing the
components of the whole range of distinguishable colours is set out in
the following tables:--
-------------+-------------+------------
Monochromes | Monochromes |Monochromes
of a Standard|Brighter than|Duller than
Brightness. | Standards. |Standards.
-------------+-------------+------------
R. | R. L. | R. Bk.
O. | O. L. | O. Bk.
Y. | Y. L. | Y. Bk.
G. | G. L. | G. Bk.
B. | B. L. | B. Bk.
V. | V. L. | V. Bk.
-------------+-------------+------------
[Illustration]
The separation of the six monochromatic sensations from a point of
white light, and the formation of binary sensations by the combination
of adjacent colours, is graphically illustrated in the above diagram.
In order to make the qualitative symbols quantitative it is only
necessary to add the numerical unit value to each factor as found by
direct experiment.