profile/profcheck
Summary
Check an ICC profile
against .ti3 test chart
data.
Usage Summary
profcheck [-options]
data.ti3 iccprofile.icm
-v
Verbose - print each patch value
-c
Show CIE94 delta E values
-k
Show CIEDE2000 delta E values
-w
create VRML visualization (iccprofile.wrl)
-x
Use VRML axes
-e
Color vectors acording to delta E
-d devval1,deval2,devvalN
Specify a device value to sort
against
-p
Sort device value by PCS/Lab target
-i
illum Choose
illuminant for print/transparency spectral data:
A, D50 (def.), D65, F5, F8, F10 or
file.sp
-o observ
Choose CIE
Observer
for spectral data:
1931_2
(def.),
1964_10, S&B
1955_2, shaw, J&V 1978_2
-f
Use Fluorescent Whitening Agent
compensation
data.ti3
Test
point data file
iccprofile.icm Profile to check
Usage Details and Discussion
profcheck provides a way of checking how well an ICC profile conforms to the test
sample data that was used to create it (or other test samples
that are from the same device). This is the same sort of check done
within
the profile making utility (colprof), but
having a
separate utility provides some flexibility. The absolute forward
table in the profile is used to create PCS values from the sample
points, and the profiles PCS value then compared to the PCS values of
the measured sample points. Note the lower delta E values are not
always a better measure of how good a profile is. The aim of a profile
is to model the underlying characteristics of a device, not to
slavishly reproduce the sampled data point values. Sampled data point
values contain device variation and instrument reading inaccuracies,
and a good profiler will try and filter out this noise, resulting in
some deliberate differences between the profile and the sample points
used to create it.
The -v flag prints out extra information during the checking.
The -c option causes the differences between the test values
and
the profile prediction of the color for each device value 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 differences between the test values
and
the profile prediction of the color for each device value 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 VRML 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 VRML output.
The -e flag causes the error
vectors in the VRML output to be color coded according to their
lengths, from longest to shortest: yellow, red, magenta, blue, cyan and
green.
The -d parameters allow the specification of a particular
device value,
and the test point by test point output will be sorted by distance from
the
given device value. This can be useful in determining how well
"supported"
the profile is in a particular area of the colorspace.
If the -p flag is used in combination with the -d
parameters,
then the test point by test point output will be sorted by distance in
PCS
(Lab) space rather than distance in device space.
The -i flag allows specifying a standard or custom illumination
spectrum, applied to the spectral test point values, to compute CIE
tristimulus
values. A, D50, D65, F5, F8, F10
are a selection of standard illuminant spectrums, with D50
being the
default. If a filename is specified instead, it will be assumed to be
an
Argyll specific .sp spectrum file.
The same value should be used as was used during the creation of the
profile.
The -o flag allows specifying a tristimulus
observer, and is used to compute PCS (Profile Connection Space)
tristimulus values. The following choices are available:
1931_2 selects the standard CIE 1931 2 degree observer.
The default.
1964_10 selects the standard CIE 1964 10 degree observer.
1955_2 selects the Stiles and Birch 1955 2 degree
observer
1978_2 selects the Judd and Voss 1978 2 degree observer
shaw selects the Shaw and Fairchild 1997 2 degree
observer
The same parameter value should be used as was used during the creation
of the profile.
The -f flag enables Fluorescent Whitening Agent compensation,
which compensates for the effect a different illuminant will have, on
any Fluorescent Whitening Agent present in the reflective media. The
same setting should
be used as was used during the creation of the profile.