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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>tiffgamut</title>
<meta http-equiv="content-type" content="text/html;
charset=ISO-8859-1">
<meta name="author" content="Graeme Gill">
</head>
<body>
<h2><b>xicc/tiffgamut</b></h2>
<h3>Summary</h3>
Create a gamut file or VRML file of the color gamut of the
contents of a set of TIFF or JPEG image.<br>
<br>
<span style="font-weight: bold;">tiffgamut</span> allows creation of
gamut files from the pixel values in a
set of TIFF and/or JPEG raster images, as defined by an ICC profile,
in L*a*b* or
CIECAM02
Jab
colorspace, and can also represent the gamut as a VRML file. This
can be used for visualizing and comparing the gamut of an image to
the
colorspace it is
in, or a colorspace it might get transformed into, and can also be
used
to create an image source gamut for use with <a href="collink.html">
collink</a>.<br>
<br>
<span style="font-weight: bold;">NOTE</span> that if you are
creating
an image gamut suitable for use with the <a href="collink.html">collink</a>
<a href="collink.html#g">-g</a> or <a href="collink.html#G">-G</a>
flags, or <a href="colprof.html#g">colprof
-g</a>, use the Jab appearance space intent for appearance space
gamut
mappings, and the same input viewing
conditions to be used in <span style="font-weight: bold;">collink</span>
or <span style="font-weight: bold;">colprof</span>
using
the -c flag, i.e. "tiffgamut -pj -cmt sRGB.icm image.tif"<br>
<h3>Usage Summary</h3>
<small><span style="font-family: monospace;">tiffgamut [-v level]
[profile.icm | embedded.tif/jpg] infile1.tif/jpg
[infile2.tif/jpg ...]</span><br style="font-family: monospace;">
<span style="font-family: monospace;"> -v
Verbose</span><br style="font-family: monospace;">
<span style="font-family: monospace;">-d
sres Surface
resolution details 1.0 - 50.0</span><br style="font-family:
monospace;">
<span style="font-family: monospace;"> -w
emit
VRML .wrl file as well as CGATS .gam file</span><br
style="font-family: monospace;">
<span style="font-family: monospace;"> -n
Don't
add VRML axes or white/black point</span><br style="font-family:
monospace;">
<span style="font-family: monospace;"> -k
Add
markers for prim. & sec. "cusp" points<br>
-f perc Filter by
popularity,
perc = percent to use<br style="font-family: monospace;">
</span><span style="font-family: monospace;"> -i
intent p =
perceptual, r = relative colorimetric,</span><br
style="font-family: monospace;">
<span style="font-family: monospace;">
s
= saturation, a = absolute (default), d = profile default</span></small><small><span
style="font-family: monospace;"></span></small><br
style="font-family: monospace;">
<small><span style="font-family: monospace;"></span><span
style="font-family: monospace;"> -o
order n = normal
(priority: lut > matrix > monochrome)</span><br
style="font-family: monospace;">
<span style="font-family: monospace;">
r
= reverse (priority: monochrome >
matrix > lut)<br>
</span></small><small><span style="font-family: monospace;"> </span><span
style="font-family: monospace;">-p oride</span><span
style="font-family: monospace;"> l
=
Lab_PCS (default), j = CIECAM02 Appearance Jab</span></small><br
style="font-family: monospace;">
<small><span style="font-family: monospace;"></span><span
style="font-family: monospace;"> -c viewcond
set
appearance mode and viewing conditions for CIECAM02,</span><br
style="font-family: monospace;">
<span style="font-family: monospace;"></span><span
style="font-family: monospace;"></span></small><small><span
style="font-family: monospace;">
either
an enumerated choice, or a parameter:value change</span><span
style="font-family: monospace;"></span><br style="font-family:
monospace;">
<span style="font-family: monospace;"></span></small><small><span
style="font-family: monospace;">
pp - Practical Reflection
Print
(ISO-3664 P2)</span><br style="font-family: monospace;">
<span style="font-family: monospace;">
pe - Print evaluation environment (CIE 116-1995)<br>
</span></small><small><span style="font-family: monospace;">
pc - Critical print evaluation environment (ISO-3664 P1)</span></small><small><span
style="font-family: monospace;"></span><span style="font-family:
monospace;"></span><br style="font-family: monospace;">
<span style="font-family: monospace;">
mt - Monitor in typical work environment</span><br
style="font-family: monospace;">
<span style="font-family: monospace;">
mb - Monitor in bright work environment</span><br
style="font-family: monospace;">
<span style="font-family: monospace;">
md - Monitor in darkened work
environment</span><br style="font-family: monospace;">
<span style="font-family: monospace;">
jm - Projector in dim environment</span><br
style="font-family: monospace;">
<span style="font-family: monospace;">
jd - Projector in dark environment</span><br
style="font-family: monospace;">
<span style="font-family: monospace;">
pcd - Photo CD - original scene
outdoors</span><br style="font-family: monospace;">
<span style="font-family: monospace;">
ob - Original scene - Bright Outdoors</span><br
style="font-family: monospace;">
<span style="font-family: monospace;">
cx - Cut Sheet Transparencies on a viewing
box</span></small><br style="font-family: monospace;">
<small><span style="font-family: monospace;">
s:surround
n = auto, a = average, m = dim, d = dark,</span><br
style="font-family: monospace;">
<span style="font-family: monospace;">
c = transparency (default average)</span><br
style="font-family: monospace;">
<span style="font-family: monospace;">
w:X:Y:Z
Adapted white point
as XYZ (default media white)</span><br style="font-family:
monospace;">
<span style="font-family: monospace;">
w:x:y
Adapted white point as
x, y</span><br style="font-family: monospace;">
<span style="font-family: monospace;">
a:adaptation
Adaptation luminance in
cd.m^2
(default 50.0)</span><br style="font-family: monospace;">
<span style="font-family: monospace;">
b:background
Background % of image luminance (default 20)<br>
l:scenewhite Scene
white in
cd.m^2 if surround = auto (default 250)<br style="font-family:
monospace;">
</span><span style="font-family: monospace;">
f:flare
Flare
light % of image luminance (default 1)</span><br
style="font-family: monospace;">
<span style="font-family: monospace;">
f:X:Y:Z Flare color as
XYZ (default media white)</span><br style="font-family:
monospace;">
<span style="font-family: monospace;">
f:x:y
Flare color as x, y<br>
-O outputfile Override the default output filename &
extension.<br style="font-family: monospace;">
</span></small><br>
<h3>Usage Details and Discussion<br>
</h3>
The<b> -v</b> flag dumps out the ICC profile header information.<br>
<br>
The <b>-d</b> 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.<br>
<br>
The <b>-w</b> flag causes a VRML file to be produced, as well as a
gamut file.<br>
<br>
The <b>-n</b> flag suppresses the L*a*b* axes being created in
the
VRML.<br>
<br>
The <span style="font-weight: bold;">-k</span> 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.<br>
<br>
The <span style="font-weight: bold;">-f</span> <span
style="font-weight: bold;">perc</span> parameter turns on
filtering of
the raster colors. The colors from the image are clustered, and then
sorted according to popularity, and then the <span
style="font-weight: bold;">perc</span> most common percentage of
colors are used to create the gamut surface. This may be useful in
creating a source gamut mapping surface that favors the important
colors within an image, and doesn't attempt to compress the color
reproduction in order to reproduce the little used colors. A value
of <span style="font-weight: bold;">perc</span> of 90 or 80 may be
a good place
to start. Note that the filtering is performed independently on each
raster image processed, with the final gamut being the union of all
the
filtered image gamuts.<br>
<br>
The <b>-i</b> 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.<br>
<br>
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 <b>-o</b> flag,
reverses
this
order. <br>
<br>
<span style="font-weight: bold;">-p</span>: By default the gamut
will
be created in L*a*b* colorspace. If <span style="font-weight:
bold;">-pj</span> 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 <a
href="colprof.html">colprof</a>. <span style="font-weight: bold;"><br>
</span>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 <span
style="font-weight: bold;">-i</span> 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 <span style="font-weight: bold;">-ia</span> in combinations
with
<span style="font-weight: bold;">-pj</span>, then Jab with
a fixed white reference is used, which emulates an absolute CIECAM02
Jab
appearance space. <br>
<br>
The <span style="font-weight: bold;">-c</span> parameter sets the
output space to CIECAM02 appearance Jab values, and also allows
choosing
a set of viewing conditions, either by choosing a typical viewing
environment, or controlling
particular viewing condition parameters. This is only functional if
an
ICC profile is provided.<br>
<br>
The <span style="font-weight: bold;">-O</span> parameter allows the
output file name & extension to be specified independently of
the
last tiff/jpeg
filename. Note that the full filename must be specified, including
the
extension.<br>
<br>
If the TIFF or JPEG files are in a device space (ie. RGB, CMYK
etc.), then it
is
necessary to supply an ICC profile to translate the device space
values
to a CIE space value such as L*a*b* or CIECAM02 Jab space for
creating
a gamut surface. For the ICC profile provided it is then possible to
select exactly what type of conversion is used. A TIFF or JPEGfile
with an
embedded ICC profile may be supplied as the profile argument - e.g.
to
get the gamut of a tiff file that contains an embedded profile use
something like:<br>
<br>
tiffgamut image.tif image.tif<br>
<br>
If a TIFF file is
already in a CIE space such as CIELab or ICCLab, then it is not
necessary to select an ICC profile, although a PCS to PCS
colorspace profile may be chosen. All the TIFF and JPEG files
must be in the same colorspace.<br>
<br>
One or more TIFF and/or JPEG files may be specified, and the gamut
is the union of
the gamuts of each file. This is useful for creating an image
specific
gamut mapping that can be applied to a set of images with consistent
results between the images. Note that the output gamut file name
will
by default be taken from the last TIFF or JPEG file specified, with
the .gam
extension added automatically. The <span style="font-weight: bold;">-O</span>
parameter will override this default.<br>
<br>
<span style="font-weight: bold;">NOTES</span><br>
<br>
The white and black points put in the gamut are the colorspace white
and black points. For the purposes of latter gamut mapping, it is
assumed that the image should retain it's position within the
colorspace dynamic range. For an L*a*b* image, the values value
100,0,0
and 0,0,0 for white and black are assumed. An image in L*a*b* should
be
adjusted be neutral to, and sit within the dynamic range of those
white
and black points.<br>
<br>
<br>
<span style="font-weight: bold;"></span><br>
<br>
<br>
</body>
</html>
|
