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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:imagewhite Image
white in cd.m^2 if surround = auto (default 250)</span></small><br
style="font-family: monospace;">
<small><span style="font-family: monospace;"><small><span
style="font-family: monospace;">
f:flare
Flare light % of image luminance (default 1)<br>
</span></small> </span><span style="font-family:
monospace;">
g:glare Glare light % of ambient
(default 1)</span><br style="font-family: monospace;">
<span style="font-family: monospace;">
g:X:Y:Z Glare color
as XYZ (default media white)</span><br style="font-family:
monospace;">
<span style="font-family: monospace;">
g:x:y Glare 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>
To create a gamut suitable for CIECAM02 gamut mapping space in
colprof or collink, something like<br>
<br>
tiffgamut -ir -pj -cmt image.icm image.tif<br>
<br>
where the viewing conditions "mt" should the same as the source
conditions in colprof or collink.<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>
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