Operation Manual

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Preferences— Nikon Color Management
“Gamut”
In addition to gamma, profi les can be classifi ed according to
their gamut, or the range of colors that can be ex pressed us-
ing the profi le. Gamut is conventionally expressed by means
of chromaticity, a measure of color developed by the Com-
mission Internationale de l’Éclairage (CIE). The CIE system,
which is modeled on hu man color perception, maps the
physical wave lengths of light to three coordinates (known
as CIE X, Y, and Z) that give unique nu mer i cal ex pres sion
to the full range of color differences that can be per ceived
by hu mans. Chro ma tic i ty is a mea sure of col or from which
con sid er ations of bright ness have been fac tored out, giving
a two-co or di nate system.
In the chromaticity diagram at right, the complete gamut of
col ors visible to hu mans is in the area en closed by the green
line. The curved portion of the line gives the chro ma tic i ty
of “pure,” un mixed colors with wavelengths in the visible
spec trum of 380–780 nm. The blue end of the spectrum
(380 nm) is at the bot tom left corner, the red end of the
spectrum (780 nm) at the bot tom right corner. The straight
diagonal line con nect ing these two points rep re sents the dif-
fer ent shades of purple cre at ed by combining red and blue
light. The colors inside the area en closed by these lines are
created by mixing light of dif fer ent wave lengths.
No color profi le is capable of expressing the full range of col-
ors visible to the human eye. The diagram below com pares
the gam ut of col ors vis i ble to the eye with the colors that can
be ex pressed in each of the RGB profi les pro vid ed with Nikon
CMS. The gamut for each profi le is con tained in the triangle
defi ned by the three points that mark the ex tremes of red,
green, and blue for that profi le (red is at the bot tom right
corner, green at the top of the triangle, and blue at the bot-
tom left corner). The white point for each profi le is shown
by the symbol in the cen ter of the triangle.
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Color Match RGB
Apple RGB
sRGB
NTSC (1953)
Bruce RGB
Adobe RGB (1988)
CIE RGB
Wide Gamut RGB
Human