xicc/iccgamut
Create a gamut file or VRML file of the color gamut of an ICC
profile.
iccgamut allows creation of
gamut files from the forward or backwards
table of an ICC profile, in Lab or CIECAM02 Jab colorspace, and can
also
representing the gamut as a VRML file.
Usage
iccgamut [-options] profile
-v
Verbose
-d
sres Surface
resolution details 1.0 - 50.0
-w
emit VRML .wrl file as well as CGATS .gam file
-n
Don't add VRML axes or white/black point
-k
Add VRML markers for prim. & sec. "cusp" points
-f function f =
forward*, b = backwards
-i
intent p =
perceptual, r = relative colorimetric,
s = saturation, a = absolute (default), d = profile default
-o
order n = normal
(priority: lut > matrix > monochrome)
r = reverse (priority: monochrome >
matrix > lut)
-p oride l =
Lab_PCS (default), j = CIECAM02 Appearance Jab
-l
tlimit set total
ink limit, 0 - 400% (estimate by default)
-L
klimit set black ink
limit, 0 - 100% (estimate by default)
-c viewcond set
viewing conditions for CIECAM02,
either an enumerated choice, or a series of
parameters:value changes
pp - Practical Reflection Print
pe - Print evaluation environment
mt - Monitor in typical work environment
mb - Monitor in bright work environment
md - Monitor in darkened work
environment
jm - Projector in dim environment
jd - Projector in dark environment
pcd - Photo CD - original scene
outdoors
ob - Original scene - Bright Outdoors
cx - Cut Sheet Transparencies on a viewing box
s:surround a = average, m = dim, d = dark,
c = transparency (default average)
w:X:Y:Z Adapted white point
as XYZ (default media white)
w:x:y Adapted white point as
x, y
a:adaptation Adaptation luminance in cd.m^2 (default 50.0)
b:background
Background % of image luminance (default 20)
f:flare Flare
light % of image luminance (default 1)
f:X:Y:Z Flare color as
XYZ (default media white)
f:x:y Flare color as x, y
-s
Create special cube surface topology plot
profile The
name of the ICC
profile, as well as the basename of the gamut [.gam] and/or VRML [.wrl] file.
Comments
The parameters are all those that control which table in the ICC
profile to use, as well as what color space to convert it to.
The -v flag dumps out the ICC profile header information.
The -d parameter controls the level of detail displayed in the
surface. The parameter roughly corresponds to a deltaE value, so
smaller
values give greater detail. The default value is around 10, and is a
good
place to start. Small values may take a lot of time to generate, and
will
produce big files.
The -w flag causes a VRML file to be produced, as well as a
gamut file.
The -n flag suppresses the L*a*b* axes being created in
the VRML.
The -k flag adds markers for
each of the primary and secondary "cusp" points (Red, Yellow, Green,
Cyan, Blue & Magenta). No markers will be displayed if the cusps
cannot be determined.
The -f parameter allows choosing the ICC table to be used in
plotting the gamut. The backwards tables generally incorporate gamut
compression, and therefore don't reflect the native capabilities of the
device.
The -i flag selects the intent transform used for a lut based
profile. It also selects between relative and absolute colorimetric for
non-lut base profiles. Note that anything other than colorimetric may
not represent the
native capabilities of the device. The default intent will be absolute
colorimetic for L*a*b* output, and CIECAM02 appearance for Jab output.
An ICC profile is allowed to contain more than the minimum number of
elements or table needed to describe a certain transform, and may
contain redundant descriptions. By default, lut based table
information will be used first if present, followed by matrix/shaper
information, and only using
monochrome information if it is all that is present. The -o
flag,
reverses this order.
-p: By default the gamut will
be created in L*a*b* colorspace. If -pj is selected, then CIECAM02
appearance space Jab will be used for the output, and the viewing
conditions will be taken into account. Jab space is what is normally
needed to be compatible with the default intents used in colprof.
Note that the CIECAM02 output space selection by default uses
the colorimetric transform of the profile resulting in the appearance
of the native device, but that the perceptual or
saturation transforms may be used by selecting them using the -i parameter, which may give a
different result with some profiles. This may be desirable if an image
is to be transformed through the perceptual or saturation tables of a
profile as part of a link with an Argyll generated output profile,
since it will then represent the apparent gamut of the image when
subject to these tables. If the absolute colorimetric intent is chosen
using -ia in combinations with
-pj, then Jab with
a fixed white reference is used, which emulates an absolute CIECAM02
Jab
appearance space.
The -l parameter allows setting a total ink limit (TAC) for
printing
devices. If a device has a total ink limit, and hasn't been
characterised with device values above this limit, then plotting the
gamut in these areas will almost certainly be misleading. tables. By
default, a total ink limit will
be estimated from the profile tables. The ink limit
will be in final calibrated device values if the profile includes
calibration information.
The -L parameter allows setting a black ink limit for printing
devices. If a device is to be used with a black ink limit, then it is
useful to evaluate
the gamut with the limit in place. By default, a black ink limit will
be estimated from the profile tables. The ink limit
will be in final calibrated device values if the profile includes
calibration information.
The -c parameter allows setting the CIECAM02 viewing
conditions,
either by choosing a typical viewing environment, or controlling
particular viewing condition parameters.
The -s flag creates a special
hyper-cube surface plot that is artificially colored. This can be
useful for identifying the topology of the black ink color response.
Example
To create a view in L*a*b* of the absolute gamut of a CMYK file with an
ink limit of 260%, one might use:
iccgamut -w -ff
-ia -l260 profile.icm
and the resulting files will be profile.gam and profile.wrl.