profile/invprofcheck
Summary
Check ICC forward against
reverse
lookup.
Usage Summary
usage: invprofcheck
[-options] profile.icm
-v [level]
verbosity level (default 1), 2 to print each DE
-l
limit set total ink
limit (estimate by default)
-L
klimit
set black channel ink
limit (estimate by default)
-h
high
res test (27)
-u
Ultra
high res test (61)
-R res Specific grid
resolution
-I
Do bwd to fwd check
-c
Show
CIE94 delta E values
-k
Show
CIEDE2000 delta E values
-w
create
X3DOM visualisation (profile.x3d.html)
-x
Use
X3DOM axes
-e
Color
vectors acording to delta E
profile.icm
Profile to check
Usage Details and Discussion
invprofcheck provides a way of checking how well an ICC profile inverse transform
inverts
the forward transform. For devices with more than 4 channels, a
total
ink limit is assumed, and (if no -l
parameter is given) a reasonable number is deduced from the reverse
table. A grid of device values is created, and the transform from
PCS->device, and then device->PCS is computed in L*a*b* space.
The average, maximum and RMS error delta E values are computed and
displayed in the chosen delta E metric. A X3DOM plot of the error vectors
can
be created. invprofcheck
tries
to only test in-gamut color values. Note that because it scans a
device
grid, for a CMYK device, the density of test points will be
progressively higher in the dark regions, and the average and RMS
values will be distorted by the denser sampling.
The -v flag prints out extra information during the
checking. A
value greater than 1 will print the color values of each test point.
The -l flag 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. The ink
limit
will be in final calibrated device values if the profile includes
calibration information.
The -L flag allows setting a black channel ink limit for
printing
devices. If a device has a black 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. The black
ink
limit
will be final calibrated device values if the profile
includes calibration information.
The default device grid is relativy low, and 11 (ie. 11 x 11 x 11
for
an RGB device, 11 x 11 x 11 x 11 for a CMYK device etc.).
The -h flag selects a
higher
device grid resolution of 27.
The -u flag selects an
extremely high device grid resolution of 61. This will probably take
a
long time to run.
The -G res option allows a
specific grid resolution to be used.
If the -I option is used, then the grid is in L*a*b* space,
so out of gamut clipping behavior can be examined. Delta E's will be
high due to the clipping.
The -c option causes the error differences to be
displayed
in CIE94 delta E, rather than plain L*a*b* delta E. CIE94 delta E
has a
closer
correspondence with perceived color differences than the default
CIE76
delta E values.
The -k option causes the error differences to be
displayed
in CIEDE2000 delta E, rather than plain L*a*b* delta E. CIEDE2000
delta
E has a
closer
correspondence with perceived color differences than either CIE76 or
CIE94 delta E values.
The -w creates a X3DOM
3D
visualization
of the differences between the test points and the profiles
prediction
of
the resulting colors.
The -x flag adds Lab axes to the X3DOM output.
The -e flag causes the
error
vectors in the X3DOM output to be color coded according to their
lengths, from longest to shortest: yellow, red, magenta, blue, cyan
and
green.