xicc/iccgamut
Create a gamut file or X3DOM 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 X3DOM file.
See 3D Viewing Format for switching to
VRML or X3D output format.
Usage
iccgamut [-options] profile
-v
Verbose
-d
sres Surface resolution
details 1.0 - 50.0
-w
emit
X3DOM .x3d.html file as well as CGATS .gam file
-n
Don't
add X3DOM axes or white/black point
-k
Add
X3DOM 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 (ISO-3664 P2)
pe - Print evaluation environment (CIE 116-1995)
pc - Critical print evaluation environment (ISO-3664 P1)
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
n = auto, 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)
l:imagewhite Image
white in cd.m^2 if surround = auto (default 250)
f:flare
Flare light % of image luminance (default 0)
g:glare Glare light % of ambient
(default 5)
g:X:Y:Z Glare color as XYZ
(default media white)
g:x:y Glare color as
x, y
-x pcent
Expand/compress gamut cylindrically by percent
-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 X3DOM [.x3d.html] 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.
Using -v -w will also print the gamut volume in
cubic L*a*b* units.
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 X3DOM file to be produced, as well as a
gamut file.
The -n flag suppresses the L*a*b* axes being created in the
X3DOM.
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 -x parameter allows expanding or compressing the
resulting gamut in a cylindrical direction by the given percentage
:- i.e "-x 120" will expand by 20%. This may be useful for creating
a general compression gamut mapping by using such an expanded device
gamut as input to collink -g or -G.
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.x3d.html.
To create a gamut suitable for CIECAM02 gamut mapping space in
colprof or collink, something like
iccgamut -ir -pj -cmt profile.icm
where the viewing conditions "mt" should the same as the source
conditions in colprof or collink.