The
a intent, Absolute
Colorimetric, is intended to reproduce colors exactly,
irrespective of the white point of the each medium. This is done
using CIECAM02 Jab appearance colorspace by forcing the source and
destination to have a common white point (but other aspects of the
individual viewing conditions are active), and colors are mapped
directly from source to destination, clipping any out of gamut
colors to the closest match. This is equivalent to the ICC
Absolute Colorimetric intent,
and is often used for proofing purposes.
The
aw
intent, Absolute Colorimetric with scaling to fit white point, is
very similar to the
a
intent, except that it will scale the source colorspace down in
order to make sure that the source white point isn't clipped by
the gamut of the destination. This might be used in some print
proofing situations where the source white is lightly lighter than
the destination white (as an alternative to using the
-w flag), or it may be useful in some soft
proofing situations where the differences in white point of the
display destination would cause clipping of the source white
point. When the
-v flag is on, the scaling
factor used will be displayed during execution.
The
aa
intent, Absolute Appearance, simply maps the Jab colors directly
from source to destination, clipping any out of gamut colors to
the closest match. This attempts to match the exact appearance of
colors as closely as possible, but may not exactly map the white
point of the source to the destination, depending on how different
the viewing conditions are.
The
r
intent is like Absolute Appearance mode, but maps the white point
from source to destination precisely, and otherwise maps the Jab
colors directly from source to destination, clipping any out of
gamut colors to the closest match. This is equivalent to the ICC
Relative Colorimetric intent.
The
la
intent, Luminance matched appearance, linearly compresses or
expands the the luminance axis to match the source to the
destination space, while not otherwise altering the gamut,
clipping any out of gamut colors to the closest match. This is
often useful for appearance based soft proofing.
The
p
intent, Perceptual, uses "knee" type 3 Dimensional compression to
make the source gamut fit within the destination gamut. As much as
possible, clipping is avoided, hues and the overall appearance is
maintained. The white point is mapped precisely from source to
destination.This is equivalent to the ICC
Perceptual intent.
The
pa
intent, Perceptual Appearance uses "knee" type 3 Dimensional
compression to make the source gamut fit within the destination
gamut. As much as possible, clipping is avoided, hues and the
overall appearance is maintained. The white point is
not mapped from source to
destination, allowing the apperance parameters to alter the
chromatic mapping.
The
ms
intent, Saturation, uses 3 Dimensional compression and
expansion to try and
make the source gamut exactly match the destination gamut, and
also favours higher saturation over hue or lightness preservation.
The white point is mapped precisely from source to destination.
The
s intent, Enhanced Saturation,
uses the same basic gamut mapping as
ms, Saturation, but increases saturation slightly
in highly saturated areas of the gamut. This is equivalent to the
ICC
Saturation intent.
The white point is mapped precisely from source to destination.
The
al
intent, Absolute Appearance (Lab), is similar to intent
a, but L*a*b* colorspace is
used rather than CIECAM02 Jab appearance space. This often leads
to poor reproduction of blue and red hues, but can be useful as a
reference mapping.