Lightness and Brightness and Other Confusions

in for instance the yellow to red quadrant. The same problem is present in the
CIELAB-space – and for the same reasons. 79
There is an important difference to all of the above in the NCS system and its
six elementary colours. This is why the NCS elementary colours are sometimes
described as “psychological primaries”. Their idea is in mapping the
visual relationships within human colour vision. In other words, the elementary
experiences of redness, greenness, yellowness and blueness describe,
together with the experiences of blackness and whiteness, our experience of
how colours resemble each other or how they are different. The six elementary
colours are not colours in any physical sense any more than the cardinal
compass points are real places in the world. Unlike almost all other colour
systems the NCS does not make any claims, with or without its layout of the
elementary colours, about the cause or origin of colours or about how to derive
more colours from the elementary ones. This means that the percentages
in the codes, such as the 30% of redness in Y30R, refer to relative visual similarity
and not to any means of producing the colour.
How many are the primaries?
The notion that the primaries are three in number is relatively new and really
gained momentum only after the invention of colour intaglio printing by
Jacob Cristoph Le Blon around 1710. It was quickly discovered that three
printing plates, inked with red, yellow and blue, were sufficient for producing
an acceptable gamut of nuances in a full colour image. Minimizing costs and
maximizing profits was the goal in the printing industry right from the beginning.
This was the aim of Le Blon, also. So minimizing the number of plates
or printing blocks would probably have made sense to anybody in the days
when the plates were prepared by hand. 80
To be accurate, Ostwald’s primaries were yellow, red, ultramarine blue and “sea
green”, and since Ostwald’s system was based on colour samples, their visual definition
relied on the pigments available at the time. There might have been a similar reason for
the contradiction between theory and practice in Itten’s circle: to yield all the mixtures
Itten was after, he should have used the modern colorants of the printing process, cyan,
magenta and yellow. But magenta and cyan were not available as artists’ pigments in
Itten’s time. It is only quite recently that near equivalents of them have become available.
This did not mean, however, that only three or four plates or blocks were used forever
from there on. In the effort for maximum quality and attractiveness they increased to
as many as forty in some branches of the advertising and packaging industry in the late
19 th Century. With the rapid development the printing process and the discovery of
more and more vivid and lightfast synthetic colorants and pigments it is no longer
necessary to engage so many printings, but in higher quality colour inkjet printing of
today the former CMYK, or three colours plus black, have been replaced by five, six or
even eleven inks.
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