60 MaP Design
Thus, when we speak of color, we are not only describing its basic hue, but also
describing its lightness or darkness and its saturation.
coloR sPecIfIcAtIon systems
In the previous sections we spoke of light or dark blue, greenish blue, or reddish blue
and we identified colors as high or low lightness or high or low saturation. But if we
attempt to describe a specific color, we are not sure that our listener is visualizing the
same color. Anyone who has attempted to describe a particular shade of blue to a
painter and been surprised at the result is familiar with this problem. One solution,
when dealing with a painter, is to provide a colored chip to match. But for many pur-
poses, it is not feasible to provide color chips and a means must be found to describe
colors. Several systems have been devised. I briefly describe three of the most com-
mon here, although anyone who intends to work intensively with color should consult
one of the references for a fuller discussion.
cIe system
The Commision International de l’Eclarage (CIE), also called the International Com-
mission on Illumination (ICI), utilizes a system based on standard illuminants, a
standard observer, and standard primaries. Any color can be described precisely in
numerical terms. It is used by the National Bureau of Standards and the National
Geospatial-Intelligence Agency (NGA). It is based on the additive, not the subtrac-
tive, primaries; therefore, it is not as useful for printed map design as the other com-
monly used systems.
