SECTION 4.5
261
Color Spaces
See Section 7.6.4, “Rendering Parameters and Transparency,” and in particular
the role of rendering intents in the transparent imaging model.
TABLE 4.20 Rendering intents
NAME
DESCRIPTION
AbsoluteColorimetric
Colors are represented solely with respect to the light source; no
correction is made for the output medium’s white point (such as
the color of unprinted paper). Thus, for example, a monitor’s
white point, which is bluish compared to that of a printer’s pa-
per, would be reproduced with a blue cast. In-gamut colors are
reproduced exactly; out-of-gamut colors are mapped to the
nearest value within the reproducible gamut. This style of repro-
duction has the advantage of providing exact color matches
from one output medium to another. It has the disadvantage of
causing colors with
Y
values between the medium’s white point
and 1.0 to be out of gamut. A typical use might be for logos and
solid colors that require exact reproduction across different me-
dia.
Colors are represented with respect to the combination of the
light source and the output medium’s white point (such as the
color of unprinted paper). Thus, for example, a monitor’s white
point would be reproduced on a printer by simply leaving the
paper unmarked, ignoring color differences between the two
media. In-gamut colors are reproduced exactly; out-of-gamut
colors are mapped to the nearest value within the reproducible
gamut. This style of reproduction has the advantage of adapting
for the varying white points of different output media. It has the
disadvantage of not providing exact color matches from one me-
dium to another. A typical use might be for vector graphics.
Colors are represented in a manner that preserves or emphasizes
saturation. Reproduction of in-gamut colors may or may not be
colorimetrically accurate. A typical use might be for business
graphics, where saturation is the most important attribute of the
color.
RelativeColorimetric
Saturation