<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>collink</title>
<meta http-equiv="content-type" content="text/html;
charset=ISO-8859-1">
<meta name="author" content="Graeme Gill">
</head>
<body>
<h2><b>link/collink</b></h2>
<h3>Summary</h3>
Link two ICC device profiles to create an ICC device link profile.<br>
<br>
<b> collink</b> takes two device ICC profiles, and links them
together,
either in a simple fashion using the standard ICC forward and
reverse
tables of the specified intent, or using color appearance space and
true gamut mapping, together with possibly inverting the forward
profile, to allow black ink regeneration or to retain the
source
black characteristic from the source profile.<br>
<h3>Usage Summary</h3>
<small><span style="font-family: monospace;">collink [-options] <span
style="font-style: italic;">srcprofile dstprofile
linkedprofile</span></span><br style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#v">-v</a><span
style="font-family: monospace;">
Verbose<br>
</span></small><small><span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#A">-A "manufacturer"</a><span
style="font-family: monospace;"> Set the manufacturer
description string</span><br style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#M">-M "model"</a><span
style="font-family: monospace;">
Set the model
description string</span><br style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#D">-D "description"</a><span
style="font-family: monospace;"> Set the
profile Description string (Default "</span><span
style="font-style: italic; font-family: monospace;">inoutfile</span><span
style="font-family: monospace;">")</span><br style="font-family:
monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#C">-C "copyright"</a><span
style="font-family: monospace;"> Set the
copyright
string</span></small><br style="font-family: monospace;">
<small><span style="font-family: monospace;"></span><span
style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#V">-V</a><span
style="font-family: monospace;">
Verify
existing
profile, rather than link (Debug
option)</span><br style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#q">-q lmhu</a><span
style="font-family: monospace;">
Quality -
Low, Medium (def), High, Ultra</span><br style="font-family:
monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#r">-r <i>res</i></a><span
style="font-family: monospace;">
Override
clut
res. set by -q</span><br style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#n">-n</a><span
style="font-family: monospace;">
Don't
preserve
device curves in result</span><br style="font-family:
monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#f">-f</a><span
style="font-family: monospace;">
Special
:- Force neutral colors to be K only output.<br>
</span></small><small><span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#fk">-fk</a><span
style="font-family: monospace;">
Special
:- Force K only neutral colors to be K only output<br>
</span></small><small><span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#fcmy">-fcmy</a><span
style="font-family: monospace;">
Special :- Force 100% C,M or Y only to stay pure</span></small><br
style="font-family: monospace;">
<small><span style="font-family: monospace;"></span><span
style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#F">-F</a><span
style="font-family: monospace;">
Special
:- Force all colors to be K only output.</span><br
style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#p">-p aprof.icm</a><span
style="font-family: monospace;">
Include
abstract
profile in link</span><br style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#s">-s</a><span
style="font-family: monospace;">
Simple
Mode
(default)</span><br style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#g">-g [src.gam]</a><span
style="font-family: monospace;">
Gamut
Mapping Mode
[optional source image gamut]</span><br style="font-family:
monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#G">-G [src.gam]</a><span
style="font-family: monospace;">
Gamut
Mapping Mode using
inverse outprofile A2B [optional source gamut]</span><br
style="font-family: monospace;">
<br style="font-family: monospace;">
<span style="font-family: monospace;"> </span><u
style="font-family: monospace;">Simple Mode Options:</u><br
style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#si">-i <i>in_intent</i></a><span
style="font-family: monospace;">
p = perceptual, r = relative colorimetric,</span><br
style="font-family: monospace;">
<span style="font-family: monospace;">
s
= saturation, a = absolute colorimetric</span><br
style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#so">-o </a><i
style="font-family: monospace;"><a href="#so">out_intent</a> </i><span
style="font-family: monospace;"> p =
perceptual, r =
relative colorimetric,</span><br style="font-family: monospace;">
<span style="font-family: monospace;">
s
= saturation, a = absolute colorimetric</span><br
style="font-family: monospace;">
<br style="font-family: monospace;">
<span style="font-family: monospace;"> </span><u
style="font-family: monospace;">Mapping Mode Options:</u><br
style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#i">-i <i>intent</i></a><span
style="font-family: monospace;">
set
linking intent from the following choice:</span><br
style="font-family: monospace;">
<span style="font-family: monospace;">
a
-
Absolute Colorimetric (in Jab) [ICC
Absolute Colorimetric]<br>
aw
-
Absolute Colorimetric (in Jab) with scaling to fit white point<br
style="font-family: monospace;">
</span><span style="font-family: monospace;">
aa
-
Absolute Appearance</span><br style="font-family: monospace;">
<span style="font-family: monospace;">
r
-
White Point Matched Appearance [ICC
Relative Colorimetric]</span><br style="font-family: monospace;">
<span style="font-family: monospace;">
la
-
Luminance matched Appearance</span><br style="font-family:
monospace;">
<span style="font-family: monospace;">
p
-
Perceptual (Preferred) [ICC Perceptual]<br>
</span></small><small><span style="font-family: monospace;">
pa
- Perceptual Appearance</span></small><br style="font-family:
monospace;">
<small><span style="font-family: monospace;"></span><span
style="font-family: monospace;">
ms
-
Saturation</span><br style="font-family: monospace;">
<span style="font-family: monospace;">
s
-
Enhanced Saturation [ICC
Saturation]</span><br style="font-family: monospace;">
<span style="font-family: monospace;">
al
-
Absolute Colorimetric (Lab)</span><span style="font-family:
monospace;"></span><br style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#w">-w [J,a,b]</a><span
style="font-family: monospace;"> Use forced
whitepoint hack [optional color to map the white to]</span><br
style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#c">-c <i>viewcond</i></a><span
style="font-family: monospace;"> set source
viewing conditions for CIECAM02,</span><br style="font-family:
monospace;">
<span style="font-family: monospace;">
either
an enumerated choice, or a parameter</span><br
style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#d">-d <i>viewcond</i></a><span
style="font-family: monospace;"> set destination
viewing conditions for CIECAM02,</span><br style="font-family:
monospace;">
<span style="font-family: monospace;">
either
an enumerated choice, or a parameter:value change<br>
</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><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><br style="font-family: monospace;">
<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
Adaptatation
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</span><br style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#t">-t <i>tlimit</i></a><span
style="font-family: monospace;">
set
source
total ink limit, 0 - 400% (estimate by default)</span><br
style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#T">-T <i>klimit</i></a><span
style="font-family: monospace;">
set
source
total ink limit, 0 - 100% (estimate by default)</span><br
style="font-family: monospace;">
<br style="font-family: monospace;">
<span style="font-family: monospace;"> </span><u
style="font-family: monospace;">Inverse outprofile A2B Options:</u><br
style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#k">-k tezhxr</a><span
style="font-family: monospace;">
CMYK
Black
generation</span><br style="font-family: monospace;">
<span style="font-family: monospace;">
t
= transfer K from source to destination, e = retain K of
destination B2A table</span><br style="font-family: monospace;">
<span style="font-family: monospace;">
z
= zero K, h = 0.5 K, x = maximum
K, r = ramp K (default)</span><br style="font-family:
monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#kp">-k p stle stpo enpo
enle
shape</a><br style="font-family: monospace;">
<span style="font-family: monospace;">
p
= black level generation curve parameters</span><br
style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#kq">-k q stle0 stpo0
enpo0
enle0 shape0 stle2 stpo2
enpo2 enle2 shape2</a><br style="font-family: monospace;">
<span style="font-family: monospace;">
q
= transfer source K to dual curve limits</span><br
style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#K">-K parameters</a><span
style="font-family: monospace;">
Same as
-k, but
target is K locus rather than K value itself</span><br
style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#l">-l <i>tlimit</i></a><span
style="font-family: monospace;">
set
destination
total ink limit, 0 - 400% (estimate by default)</span><br
style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#L">-L <i>klimit</i></a><span
style="font-family: monospace;">
set
destination
total ink limit, 0 - 100% (estimate by default)<br>
</span></small> <small><span style="font-family:
monospace;"><a href="#P">-P</a>
Create
gamut
gammap_p.wrl and gammap_s.wrl diagostics</span></small><small><br>
<br>
<span style="font-family: monospace;"></span></small><span
style="font-family: monospace;"> <span
style="text-decoration: underline;"><span style="font-style:
italic;"></span></span></span><a href="#p1"><i
style="font-family: monospace;">srcprofile</i></a><span
style="font-family: monospace;">
source
ICC
profile. A </span><small><span style="font-family: monospace;">TIFF
or JPEG
file with embedded profile may be
used here.</span></small><br style="font-family: monospace;">
<span style="font-family: monospace;"><span style="text-decoration:
underline;"><span style="font-style: italic;"></span></span></span><a
href="#p2"><i style="font-family: monospace;">dstprofile</i></a><span
style="font-family: monospace;">
destination
ICC
profile. </span><span style="font-family: monospace;">A
</span><small><span style="font-family: monospace;">TIFF or JPEG
file with
embedded profile may be used here.</span></small><br
style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a href="#p3"><i
style="font-family: monospace;">linkedprofile</i></a><span
style="font-family: monospace;">
resulting device link
profile</span><br>
<h3>Usage Details and Discussion</h3>
<b><a name="v"></a> -v</b> Turns on verbose mode. Gives progress
information as the profile is created. Since gamut map mode inverse
profile linking can take a long time to perform, this is often
useful. <br>
<br>
<a name="A"></a>The <b>-A</b> parameter allows setting of the
device
manufacturer description tag. This parameter may not be relevant for
a
link profile, but if used should be a string that
identifies the manufacturer of the primary device used in the link.
With most
command line shells, it will be necessary to enclose the parameter
with double quotes, so that spaces and other special characters are
included in the parameter, and not mistaken for the start of another
flag, or as a final command line parameters. By default no
manufacturer
description string tag will be generated for the profile.<br>
<br>
<a name="M"></a>The <b>-M</b> parameter allows setting of the
device
mode description tag. This parameter may not be relevant for a link
profile, but if used should be a string that
identifies the particular model of primary device used in the link.
With most command line
shells, it will be necessary to enclose the parameter with double
quotes, so that spaces and other special characters are included in
the
parameter, and not mistaken for the start of another flag, or as a
final command line parameters. By default no model description
string
tag will be generated for the profile.<br>
<br>
<a name="D"></a>The <b>-D</b> parameter allows setting of the
profile
description tag. The parameter should be a string that describes the
profile. On many systems, it will be this string that will be used
to
identify the profile from a list of possible profiles. With most
command line shells, it will be
necessary to enclose the parameter with double quotes, so that
spaces
and other special characters are included in the parameter, and not
mistaken for the start of another flag, or as a final command line
parameter. Many programs that deal with ICC profiles use the
description tag to identify a profile, rather than the profile
filename, so using a descriptive string is important in being able
to
find a profile. By default, the base name of the resulting profile
will
be used as the description.<br>
<br>
<a name="C"></a>The <b>-C</b> parameter allows setting of the
profile
copyright tag. The parameter should be a string that describes the
copyright (if any) claimed on the profile being generated.. With
most
command line shells, it will be necessary to enclose the parameter
with double quotes, so that spaces and other special characters are
included in the parameter, and not mistaken for the start of another
flag, or as a final command line parameters. By default a generic
copyright string will be generated for the profile.<br>
<br>
<br>
<b><a name="V"></a> -V</b> Verifies an existing profile. This is
really
a debugging option. It is only useful if all the linking parameters
are
identical
to those used during the creation of the profile being verified.<br>
<br>
<b><a name="q"></a> -q [lmhu]</b> Quality
-
Low, Medium
(def), High, Ultra<br>
<b><a name="r"></a> -r res </b>
Override clut res. set by <b>-q</b><br>
<br>
This sets the basic quality of the resulting link, by choosing the
resolution of various tables in the resulting profile, as well as
the
resolution of other temporary tables used in creating the link. The
<b>-r</b>
flag allows overriding the resolution set by the <b>-q</b> option,
for
the ICC profile CLUT multi-dimensional interpolation table. It is
highly recommended that <span style="font-weight: bold;">-qm</span>
be
used as a starting point, and other settings only tried after this
has
been evaluated. <span style="font-weight: bold;">-qu</span> should
almost never be used, except to prove that it should almost never be
used.<br>
<br>
<a name="n"></a>Normally the per channel device curves in the source
and destination
profiles
are preserved in the resulting device link profile, but the <b>-n</b>
option disables this. This can be useful if the device linearisation
curves
are inappropriate in nature.<br>
<br>
<a name="f"></a> The <b>-f</b> option
is a special
purpose flag useful
only for 3 or 4 component (RGB, CMY or CMYK) source to CMYK
destination
linking, that
causes the destination to be
<span style="font-weight: bold;">K only</span> for neutral axis
input.
Neutral axis input is assumed for R=G=B
or
C=M=Y input values. So as to get a smooth mapping from the source to
the K only destination, by default the gamut mapping will be
adjusted
to target
the destination K only black, and Perceptual gamut mapping
will be selected along with maximum K inking. If other options are
selected that conflict with achieving a smooth mapping, warnings
messages will
be emitted.<br>
<br>
<a name="F"></a> The <b>-F</b> option
is a special
purpose flag useful
only mapping to a CMYK destination, that
causes the destination to be
converted to K only monochrome. So as to get a smooth mapping from
the
source to
the K only destination, by default the gamut mapping will be
adjusted
to target
the destination K only black, and Perceptual gamut mapping
will be selected along with maximum K inking. If other options are
selected that conflict with achieving a smooth mapping, warnings
messages will
be emitted.<br>
<br>
<a name="fk"></a> The <b>-fk</b> option
is a special
purpose flag useful
only for CMYK source to CMYK destination
linking, that
causes K only source values to map to K only destination values.
This
is often useful in re-targeting CMYK material while preserving K
only
text and graphics. So as to get a smooth mapping from the source to
the K only destination, by default the gamut mapping will be
adjusted
to assume K only black source to destination K only black for K only
values, and Perceptual gamut mapping
will be selected along with a black generation rule (<span
style="font-weight: bold;">-kt</span>) that preserves the black
level
from source to destination. If other options are
selected that conflict with achieving a smooth mapping, warnings
messages will
be emitted.<br>
<br>
<a name="fcmy"></a> The <b>-fcmy</b> options
are special
purpose flags useful
only for CMY or CMYK source to CMY or CMYK destination
linking. The <span style="font-weight: bold;">cmy</span> flags may
be
used independently or in combination (ie. <span style="font-weight:
bold;">-fc, -fm, -fy, -fcm, -fcy, -fmy, -fcmy</span>)
or
combined with the <span style="font-weight: bold;">-fk</span>
option. These flags ensure that the pure 100% primary colorant
source values map to 100% pure colorant destination values, and may
be
useful in some situations where CMYK material is being re-targeted.
<span style="font-weight: bold;">Note</span> that forcing the 100%
colorant
values to map this way largely works against the aims of color
management in preserving colors appearance. So as to get a
smooth
mapping from the source to destination, by default the gamut
mapping will a Saturation intent with 100 percept alignment of the
selected C, M and/or Y cusp values. A Saturation intent is often
what
is desired in such CMYK to CMYK re-renderings, as it makes best use
of
the (usually quite similar sized) destination gamut. If other
options
are
selected that conflict with achieving a smooth mapping, warnings
messages will
be emitted.<br>
<br>
<a name="p"></a> The <b>-p</b> option alows specifying an abstract
profile be applied between the source and destination profiles. An
abstract
profile is a way of specifying a color adjustment in a device
independent way. The abstract profile might have been created using
one
of the <span style="font-weight: bold;">tweak</span> tools, such as
<a href="refine.html">refine</a>.<br>
<br>
The basic linking style is chosen by using the <b>-s</b> (default),
<b>-g</b>
or <b>-G</b> flags. The three behaviors are:<br>
<br>
<a name="s"></a> <b>-s</b> Simple mode. No gamut
mapping is performed, the selected intent AtoB and BtoA tables are
simply concatenated to create the output link, with the gamut
mapping
behavior being determined solely by the BtoA table. The -i and -o
options allow selection of the source and destination ICC intents.
This
is
typically how other CMS do ICC linking. <a href="#ss">Details</a>.<br>
<br>
<a name="g"></a> <b>-g</b> Gamut mapping mode. In
this mode, the absolute colorimetric AtoB and BtoA tables are used
to
perform the link, and the intermediate linking color space is
(generally) the CIECAM02 Jab appearance space. The source and
destination
viewing conditions can be selected using the <b>-c</b> and <b>-d</b>
options. A gamut mapping is performed between the two spaces,
using the intent selected by the <b>-i</b> option. There is
an
optional argument, which is a source gamut to use
instead of that of the source profile. This is to allow optimizing
the
gamut mapping to a source gamut of a particular image, which
can
give slightly better results that gamut mapping from the gamut of
the
source colorspace. Such a source image gamut can be created using
the <a href="tiffgamut.html"> tiffgamut</a> tool. More <a
href="#gg">details</a>
about gamut mapping mode.<br>
<br>
<a name="G"></a> <b>-G</b> Use the gamut mapped, inverse
AtoB table linking method. This is generally the most accurate,
smooth
and flexible linking method, but takes the longest to perform. The
gamut mapping mode (<span style="font-weight: bold;">-g</span>)
options <b>-i</b>, <b>-c</b>, <b>-d</b>, <b>-k</b> and <b>-l</b>
are effective when this method is selected. There is an optional
argument, which is a source gamut to use instead of that of the
source
profile. This is to allow optimizing the gamut mapping to a source
gamut of a particular image, which can give slightly better
results that gamut mapping from the gamut of the source colorspace.
Such a source image gamut can be created using the <a
href="tiffgamut.html"> tiffgamut</a> tool. More <a href="#GG">details</a>
about the gamut mapping, inverse AtoB mode.<br>
<br>
The gamut provided to the <span style="font-weight: bold;">-g</span>
or <span style="font-weight: bold;">-G</span> flag should be in the
same colorspace that <span style="font-weight: bold;">collink</span>
is using internally to connect the two profiles. For all intents
except
the last one (no. <span style="font-weight: bold;">7</span>),
the space should be Jab appearance space, with the viewing
conditions generally being those of the source profile viewing
conditions. The source profile will normally be the one used to
create
a
source image gamut using <span style="font-weight: bold;">tiffgamut</span>.<br>
<br>
<u><a name="ss"></a> Simple mode gamut mapping options:</u><br>
<br>
<a name="si"></a> <b>-i</b> <i>in_intent</i>
<b>p</b> = perceptual, <b>r</b> = relative
colorimetric,<br>
<b>s</b>
=
saturation, <b>a</b> = absolute colorimetric<br>
<a name="so"></a> <b>-o</b> <i>out_intent</i>
<b>p</b> = perceptual, <b>r</b> = relative
colorimetric,<br>
<b>s</b>
=
saturation, <b>a</b> = absolute colorimetric<br>
<br>
These two options simply select the appropriate ICC table, according
to
desired intent. Generally, it is a good idea to use the same intent
for
both source and destination. Not all ICC profiles support all four
intents.<br>
<br>
<u><a name="gg"></a> Gamut mapping mode options:</u><br>
<br>
<a name="i"></a> <b>-i</b> <i>intent</i><br>
<br>
Select the gamut mapping intent. In gamut mapping mode there is
only a single overall intent. The intent is selected using the 1 two
letter option parameter, the standard ICC profile being a subset of
the
available selections.<br>
<br>
<a name="ia"></a>The <span style="font-weight: bold;">a</span>
intent, Absolute Colorimetric, is
intended to reproduce
colors exactly, irrespective of the white point of the each medium.
This
is done using CIECAM02 Jab appearance colorspace by forcing the
source
and
destination to have a common white point (but other aspects of the
individual viewing conditions are active), and colors are mapped
directly from source to destination, clipping any out of gamut
colors
to the closest match.
This is equivalent to the ICC <span style="font-weight: bold;">Absolute
Colorimetric</span> intent, and is often used for proofing
purposes. <br>
<br>
<a name="iaw"></a>The <span style="font-weight: bold;">aw</span><b
style="font-weight: bold;"></b> intent, Absolute Colorimetric with
scaling to fit white point, is very similar to the <span
style="font-weight: bold;">a</span> intent, except that it will
scale
the source colorspace down in order to make sure that the source
white
point isn't clipped by the gamut of the destination. This might be
used
in some print proofing situations where the source white is lightly
lighter than the destination white (as an alternative to using the <a
href="#w">-w</a> flag), or it may be useful in some soft proofing
situations where the differences in white point of the display
destination would cause clipping of the source white point.
When
the <a href="#v">-v</a> flag is on, the scaling factor used will be
displayed during execution.<br>
<br>
<a name="iaa"></a>The <span style="font-weight: bold;">aa</span>
intent, Absolute Appearance, simply
maps the Jab
colors directly from source to destination, clipping any out of
gamut
colors
to the closest match. This attempts to match the exact appearance of
colors as closely as possible, but may not exactly map the white
point
of the source to the destination, depending on how different the
viewing conditions are.<br>
<br>
<a name="ir"></a>The <span style="font-weight: bold;">r</span>
intent is like Absolute
Appearance mode, but maps the
white point from source to destination
precisely, and otherwise maps the Jab colors directly from source to
destination, clipping any out of gamut colors to the closest match.
This is
equivalent to the ICC <span style="font-weight: bold;">Relative
Colorimetric</span> intent.<br>
<br>
<a name="ila"></a>The <span style="font-weight: bold;">la</span>
intent, Luminance matched
appearance, linearly
compresses or expands the the luminance axis to match the source to
the
destination space, while not otherwise altering the gamut, clipping
any
out
of gamut colors to the closest match. This is often useful for
appearance based soft proofing.<br>
<br>
<a name="ip"></a>The <span style="font-weight: bold;">p</span>
intent, Perceptual, uses "knee"
type 3 Dimensional compression to
make the source gamut fit within the destination gamut. As much as
possible,
clipping is avoided, hues and the overall appearance is maintained.
The
white point is mapped precisely from source to destination.This is
equivalent to the ICC <span style="font-weight: bold;">Perceptual</span>
intent.<br>
<br>
<a name="ipa"></a>The <span style="font-weight: bold;">pa</span>
intent, Perceptual Appearance uses "knee"
type 3 Dimensional compression to
make the source gamut fit within the destination gamut. As much as
possible,
clipping is avoided, hues and the overall appearance is maintained.
The white point is<span style="font-weight: bold;"> not</span>
mapped
from source to destination, allowing the apperance parameters to
alter
the chromatic mapping.<br>
<br>
<a name="ims"></a>The <span style="font-weight: bold;">ms</span>
intent, Saturation, uses 3 Dimensional
compression
and <span style="text-decoration: underline;">expansion</span> to
try and make the source gamut exactly match the destination gamut,
and
also
favours higher saturation over hue or lightness preservation. The
white point is mapped precisely from source to destination.<br>
<br>
<a name="is"></a>The <span style="font-weight: bold;"></span><span
style="font-weight: bold;">s</span> intent, Enhanced Saturation,
uses
the same basic
gamut mapping as <span style="font-weight: bold;">ms</span>,
Saturation, but increases saturation slightly
in
highly saturated areas of the gamut. This is equivalent to the ICC <span
style="font-weight: bold;">Saturation</span> intent. The
white point is mapped precisely from source to destination.<br>
<br>
<a name="ial"></a>The <span style="font-weight: bold;">al</span>
intent, Absolute Appearance (Lab),
is similar to
intent <span style="font-weight: bold;">a</span>, but L*a*b*
colorspace is used rather than CIECAM02 Jab
appearance space. This often leads to poor reproduction of blue and
red
hues, but can be useful as a reference mapping.<br>
<br>
<a name="w"></a> The <b>-w</b> flag forces the white points to be
mapped from source to destination, irrespective of the intent
chosen.
This is useful if absolute intent is being used, and the two media
white points should match, but don't quite due to measurement error.<br>
The <b>-w</b> flag can optionally be followed by three numbers,
that
specify a color that white should be mapped to. This will be in the
colorspace used during linking (typically Jab space, which
has similar characteristics to L*a*b* space). This options can be
useful in fine tuning paper emulation in absolute
colorimetric mapping mode.<br>
<br>
<a name="c"></a><a name="d"></a> The <b>-c</b> and <b>-d</b>
options
allow specification of the viewing conditions for the source and
destination colorspaces respectively. The viewing condition
information
is used to map the profile PCS (Profile Connection Space, which us
either XYZ or L*a*b*) color into appearance space (CIECAM02), which
is a better colorspace to do gamut mapping in. The viewing
conditions
allow the conversion into appearance space to take account of how
color
will be seen under particular viewing conditions.<br>
Viewing conditions can be specified in two basic ways. One is to
select from the list of "pre canned", enumerated viewing conditions,
choosing one that is closest to the conditions that are appropriate
for
the media type and situation. Alternatively, the viewing conditions
parameters can be specified in detail individually. If both methods
are
used, them the chosen enumerated condition will be used as a base,
and
its parameters will
then be individually overridden.<br>
<br>
<a name="t"></a> The <b>-t</b> <i>tlimit</i> parameter sets the
total
ink limit (TAC, Total Area Coverage) for a CMYK source profile, as a
total
percentage from 0% to 400%. This affects the gamut assumed for the
source profile. By default, a total ink limit will
be estimated from the source profile B2A table.<br>
<br>
<a name="T"></a> The <b>-T</b> <i>klimit</i> parameter sets the
black
channel ink limit for a CMYK source profile, as a total percentage
from
0%
to 100%. This affects the gamut assumed for the source profile. By
default, a black ink limit will
be estimated from the source profile B2A table.<br>
<br>
<br>
<u> <a name="GG"></a>Inverse outprofile A2B Options:</u><br>
<br>
When the <b>-G</b> flag is used, the A2B table is inverted "on the
fly", allowing various additional choices as to what device values
are
used
to reproduce a particular color. (If the <b>-G</b> flag is not
used,
then
such decisions are encoded in the B2A table in the profile, and
cannot
be
altered during linking).<br>
<br>
<a name="k"></a> -<b>k</b> parameter sets the target level of black
(K)
when creating a B2A CMYK output tables. This is often called a black
level, a black inking rule, black generation, or under color
removal. These set the target black level:<br>
<br>
<b> -kz</b> selects minimum black (0.0)<br>
<b> -kh</b> selects a black level value of 0.5<br>
<b> -kx</b> selects the maximum possible black (1.0)<br>
<b> -kr</b> selects a linear level ramp, starting at minimum black
for
highlight, and maximum black for shadow (equivalent to -kp 0 0 1 1
1).
This is the default.<br>
<b>-kt</b>, will preserve the black amount from the source (CMYK)
profile to the destination (CMYK) profile as much as possible.
This
may
be most useful in creating a CMYK to CMYK conversion between two
different
press conditions, while preserving as much as possible the
black
only use for text etc. in anything converted. Note that if the
source
black point is darker than the destination, composite black will
still
be generated for K only input. The <span style="font-weight: bold;">-fk</span>
option can be used to avoid this behavior.<br>
<b>-ke</b>, will preserve the black amount from the destination
profile
B2A
table (CMYK).<br>
<br>
<b><a name="kp"></a>-k p stle stpo enpo enle shape</b> allows
an
arbitrary black locus ramp to be defined, consisting of a starting
value (stle) for highlights, a breakpoint L value (stpo) where it
starts to transition to the shadow level, an end breakpoint L (enpo)
where it flattens out again, and the finishing black level (enle)
for
the shadows. There is also a curve parameter, that modifies the
transition from stle to enle to either be concave (ie. the
transition starts gradually and and finished more abruptly) using
values 0.0-1.0, with 0.0 being most concave, or convex (the
transition
starts more abruptly but finishes gradually), using values 1.0-2.0,
with 2.0 being the most convex.<br>
<br>
Typical black value generation curve with parameters something
like: -kp 0 .1 .9 1 .5<br>
<br>
<tt> 1.0 K |
enpo<br>
|
_______
enle<br>
|
/<br>
|
/<br>
|
/<br>
|
/<br>
stle
| ------/<br>
+-------------------<br>
0.0 K
0.0
stpo 1.0<br>
White
Black<br>
<br>
</tt>For minimum sensitivity of printed output to the lighting
spectrum, it
currently seems best to use the maximum possible black, but other
black
generation levels (ie. 0.3 to 0.5) may well be preferred if one
wants
to
minimize the noisy appearance of black on an inkjet device, or
if the banding behaviour or other rendering flaws of the printer is
to
be minimized. <br>
<br>
<b><a name="kq"></a>-k q stle0 stpo0 enpo0 enle0 shape0 stle2 stpo2
enpo2 enle2 shape2</b> is a combination of the <b>-kt</b> and <b>-kp</b>
functionality, with the black being preserved in CMYK to CMYK
linking,
with the output black constrained to be between the first and second
set of curve parameters.<br>
<br>
The <a href="xicclu.html">xicclu</a> tool can be used to plot out
the resulting black level for a given set of parameters, by using
the <a href="xicclu.html#g">-g</a> flag of a profile already
created from the
same .ti3 file.<br>
<br>
<a name="K"></a> <span style="font-weight: bold;">-K parameters.</span>
Any of the <span style="font-weight: bold;">-k</span> options above
can use the <span style="font-weight: bold;">-K</span> version, in
which rather than a black value target being defined by the inking
rule, a black <span style="text-decoration: underline;">locus</span>
target is defined. For each lookup, the minimum possible black level
and the maximum possible black level is determined, the former
corresponding to a locus target value of 0, and the latter
corresponding to a
locus target value of 1. For instance, at
the
white point, no black will be used in the output, even if the black
locus specifies a maximum (since the maximum amount of black that
can be used to print white is actually zero). Similarly, at the
black
point, black may well be used, even if the black locus specifies
zero black (since a certain amount of black is needed to achieve the
desired density of color). <br>
<tt> </tt><br>
<a name="l"></a> The <b>-l</b> <i>tlimit</i> parameter sets the
total
ink limit (TAC, Total Area Coverage) for the CMYK separation, as a
total
percentage from 0% to 400%. This affects the gamut assumed for the
destination profile, as well as the ink limit in the generated
device
link.
The limit value should generally be set
a little below the value used in the test chart generation, to avoid
the
very edges of the gamut. If the test chart ink limit has been chosen
to
be a little beyond an acceptable level, then this number should be
the
acceptable level. Although limits can be set below 200%, this will
generally
restrict the color gamut noticeably, as fully saturated secondary
colors
will not be reproduced. Values are between 220% and 300% for typical
printing
devices. By default, a total ink limit will
be estimated from the destination profile B2A table. The ink limit
will be in final calibrated device values if the profile includes
calibration information.<br>
<br>
<a name="L"></a> The <b>-L</b> <i>klimit</i> parameter sets the
black
channel ink limit for the CMYK separation, as a total percentage
from
0%
to 100%. This affects the gamut assumed for the source profile, as
well
as the ink limit in the generated device link. For printing press
like
devices, this can be used to prevent
the
black channel screening pattern "filling in". Typical values might
be
from
95% to 99%. By default, a black ink limit will
be estimated from the source profile B2A table. The ink limit
will be in final calibrated device values if the profile includes
calibration information.<br>
<br>
<b><a name="P"></a></b>The <b>-P</b> option causes a diagnostic 3D
<a href="File_Formats.html#VRML">VRML</a> plots to be created that
illustrate the gamut mapping generated.<br>
<br>
<a name="p1"></a>The <i><b>inprofile</b></i> argument specifies the
source profile.
This is the color space/device we are attempting to emulate in the
overall conversion. A <small>TIFF or JPEG file with embedded
profile may be
used here.</small><br>
<br>
<a name="p2"></a>The<i><b> outprofile</b></i> argument specifies the
destination profile.
This is the device we are actually displaying on or printing to. A <small>TIFF
or
JPEG file
with embedded profile may be used here.</small><br>
<br>
<a name="p3"></a>The <i><b>linkedprofile</b></i> argument specifies
the resulting device link
profile. This profile will contain the color transform from the
source
space to destination space.<br>
<br>
For information on typical usage, see the <a href="Scenarios.html">Typical
Usage
Scenarios</a> page.<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
</body>
</html>
