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<h2>Description of the .ti3 format</h2>
This is an ASCII text, <a href="File_Formats.html#CGATS">CGATS</a>,
Argyll specific format, used to hold device value and CIE/Spectral
value pairs, the raw information needed to create device profiles.
This
file is typically created using the <a href="chartread.html">chartread</a>, <a
href="dispread.html"> dispread</a>,
<a href="filmread.html">filmread</a>, <a href="scanin.html"> scanin</a>,
<a href="fakeread.html"> fakeread</a> or one of the conversion
tools
such as <a href="cb2ti3.html">cb2ti3</a>, <a href="kodak2ti3.html">kodak2ti3</a>,
<a href="txt2ti3.html">txt2ti3</a>.<br>
<br>
While fully compatible with the CGATS.5 Data Exchange Format, the
particular required keywords and fields are unique to Argyll, hence
an
Argyll specific file identifier <span style="font-weight: bold;">CTI3</span>
is used to avoid confusion with standard ANSI or CGATS files.<br>
<br>
The <span style="font-weight: bold;">.ti3</span> format changes
from
time to time with new releases, to add new functionality, but
generally
retains backwards compatibility. Note that in the description below,
the word "may" indicates an optional component, while the word
"shall"
indicates a necessary component.<br>
<br>
Generally a .ti3 file contains only one table, the table containing
the
colorimetric information. The exception is for a display in which a
set
of RAMDAC values (most likely the result of display calibration, or
simply the video LUT (RAMDAC) values present in the display when the
test values
were read) are recorded in a second table.<br>
<br>
<br>
The first table contains the following:<br>
<br>
The file identifier (First 7 characters) shall be <span
style="font-weight: bold;">CTI3</span>.<br>
<br>
A <span style="font-weight: bold;">#</span> character introduces a
comment.<br>
<br>
<span style="font-weight: bold;"><span style="font-weight: bold;"><span
style="font-weight: bold;"></span></span></span>There may be <span
style="font-weight: bold;">DESCRIPTOR</span>, <span
style="font-weight: bold;">ORIGINATOR</span>, or <span
style="font-weight: bold;">CREATED</span> keywords and values (as
per
CGATS).<br>
<br>
There shall be a <span style="font-weight: bold;">DEVICE_CLASS</span>
keyword that has a value of <span style="font-weight: bold;">"OUTPUT</span>",
"<span style="font-weight: bold;">DISPLAY</span>" or <span
style="font-weight: bold;">"INPUT"</span>.<br>
This indicates to the profile program what type of device the color
information is from.<br>
<br>
An <span style="font-weight: bold;">"OUTPUT"</span> type device may
have a <span style="font-weight: bold;">TOTAL_INK_LIMIT</span>
keyword
that has a numeric value indicating the maximum sum of the device
channel values as a percentage (T.A.C.), used in creating the test
chart. This will be used by the profiler as a value indicating what
the
valid device gamut is, and what total ink limit should be used in
creating the profile tables.<br>
<br>
A <span style="font-weight: bold;">"DISPLAY"</span> type device may
have a <span style="font-weight: bold;">LUMINANCE_XYZ_CDM2</span>
keyword that contains the absolute XYZ value of white in candelas
per
meter squared, e.g. <span style="font-weight: bold;">"112.334770
119.657745 121.474236".<br>
<br>
</span>A display device may also have a <span style="font-weight:
bold;">NORMALIZED_TO_Y_100</span> keyword that
must have a value of "<span style="font-weight: bold;">NO</span>" or
"<span style="font-weight: bold;">YES</span>", to indicate whether
the CIE
values have been normalised so that the largest has a Y value of
100.
If this is a display type device and there is no <span
style="font-weight: bold;">NORMALIZED_TO_Y_100</span> keyword,
then it
can be assumed that the value <span style="font-weight: bold;">are</span>
normalized to Y = 100. If the values are normalized to Y = 100, then
the absolute values can be restored by multiplying the XYZ values by
the <span style="font-weight: bold;">LUMINANCE_XYZ_CDM2</span> Y
value
and dividing by 100.<br>
<br>
There may be a keyword <span style="font-weight: bold;">TARGET_INSTRUMENT</span>
which will identify the instrument used to read the test values.
This
is used by the profiling program to determine the spectral
characteristics of the instrument illuminant if Fluorescent Whitener
Compensation is desired. The value shall be one of:<br>
<br>
<span style="font-weight: bold;"> "Xrite DTP20"</span><br
style="font-weight: bold;">
<span style="font-weight: bold;"> "Xrite DTP22"</span><br
style="font-weight: bold;">
<span style="font-weight: bold;"> "Xrite DTP41"</span><br
style="font-weight: bold;">
<span style="font-weight: bold;"> "Xrite DTP51"</span><br
style="font-weight: bold;">
<span style="font-weight: bold;"> "Xrite DTP92"</span><br
style="font-weight: bold;">
<span style="font-weight: bold;"> "Xrite DTP94"</span><br
style="font-weight: bold;">
<span style="font-weight: bold;"> "GretagMacbeth
Spectrolino"</span><br style="font-weight: bold;">
<span style="font-weight: bold;"> "GretagMacbeth
SpectroScan"</span><br style="font-weight: bold;">
<span style="font-weight: bold;"> "GretagMacbeth
SpectroScanT"</span><br style="font-weight: bold;">
<span style="font-weight: bold;"> "Spectrocam"</span><br
style="font-weight: bold;">
<span style="font-weight: bold;"> "GretagMacbeth
i1
Display"</span><br style="font-weight: bold;">
<span style="font-weight: bold;"> "GretagMacbeth
i1
Monitor"</span><br style="font-weight: bold;">
<span style="font-weight: bold;"> "GretagMacbeth
i1
Pro"</span><br style="font-weight: bold;">
<span style="font-weight: bold;"> "X-Rite
ColorMunki"</span><br style="font-weight: bold;">
<span style="font-weight: bold;"> "Colorimtre
HCFR"</span><br style="font-weight: bold;">
<span style="font-weight: bold;"> "ColorVision
Spyder2"</span><br style="font-weight: bold;">
<span style="font-weight: bold;"> "Datacolor
Spyder3"</span><br style="font-weight: bold;">
<span style="font-weight: bold;"> "GretagMacbeth
Huey"</span><br>
<br>
All instruments except the Spectrocam are assumed to have an "A"
type
illuminant (incandescent lamp of 2850 degrees Kelvin.)<br>
<br>
There may be a <span style="font-weight: bold;">INSTRUMENT_TYPE_SPECTRAL</span>
keyword that must have a value of "<span style="font-weight: bold;">NO</span>"
or "<span style="font-weight: bold;">YES</span>", to indicate
whether
the instrument is based on spectral measurement or not.<br>
<br>
There may be keywords with associated values <span
style="font-weight: bold;">SINGLE_DIM_STEPS</span>, <span
style="font-weight: bold;">COMP_GREY_STEPS</span>, <span
style="font-weight: bold;">MULTI_DIM_STEPS</span> or <span
style="font-weight: bold;">FULL_SPREAD_PATCHES</span>, that
document
the composition of the test chart patches.<br>
<br>
There shall be a keyword <span style="font-weight: bold;">COLOR_REP</span>
that has a value that indicates what colorspaces the test values
connect. The colorspaces shall be encoded with one or two
letters
per
component, and the two color spaces shall then separated by an <span
style="font-weight: bold;"><span style="font-weight: bold;">_</span></span>
(underscore) character. For output and display devices, the device
space shall come first, followed by the PCS space. For an input
device,
the PCS shall come first, followed by the device space. The PCS
space
shall be either XYZ space, indicated by <span style="font-weight:
bold;">XYZ</span>,
or D50 while point L*a*b* space, indicated by <span
style="font-weight: bold;">LAB</span>. The device spaces shall use
the
following letter encoding:<br>
<br>
<span style="font-weight: bold;"><span style="font-weight: bold;"></span></span>
Cyan
C<br>
Magenta
M<br>
Yellow
Y<br>
Black
K<br>
Orange
O<br>
Red
R<br>
Green
G<br>
Blue
B<br>
White
W<br>
Light Cyan
c<br>
Light
Magenta
m<br>
Light
Yellow
y<br>
Light
Black
k<br>
Medium Cyan
2c<br>
Medium Magenta
2m<br>
Medium Yellow
2y<br>
Medium Black
2k<br>
Light Light Black 1k<br>
<br>
There may be an a previx <span style="font-weight: bold;">i</span>
preceeding the device space letter encoding, indicating that
although
the space appears to be an additive space, it is in fact a
subtractive
device.<br>
<br>
Typical values might be: "<span style="font-weight: bold;">RGB_XYZ</span>"
or "<span style="font-weight: bold;">RGB_LAB</span>" for an RGB
display, "<span style="font-weight: bold;">iRGB_XYZ</span>"
or "<span style="font-weight: bold;">iRGB_LAB</span>" for an RGB
printer, "<span style="font-weight: bold;">CMYK_XYZ</span>" for a
printer, "<span style="font-weight: bold;">XYZ_RGB"</span> for an
RGB
scanner.<br>
<br>
If spectral values are going to be included in the file, the
following
keywords and values shall be used:<br>
<br>
<span style="font-weight: bold;"> SPECTRAL_BANDS</span> shall
contain the number of spectral bands in the readings, e.g. <span
style="font-weight: bold;">"36"</span>.<br>
<span style="font-weight: bold;">SPECTRAL_START_NM</span>
shall
contain the wavelength in nanometers of the first band, e.g. <span
style="font-weight: bold;"><span style="font-weight: bold;"><span
style="font-weight: bold;">"380.0"</span></span></span>.<br>
<span style="font-weight: bold;">SPECTRAL_END_NM</span>
shall
contain the wavelength in nanometers of the last band, e.g. <span
style="font-weight: bold;">"730.0"</span>.<br>
<br>
The <span style="font-weight: bold;">NUMBER_OF_FIELDS</span>
keyword
shall have a value that indicates the number of fields in each data
set, e.g. <span style="font-weight: bold;">43</span> (as per
CGATS).<br>
<br>
The start of the declaration of the fields shall be marked by the <span
style="font-weight: bold;">BEGIN_DATA_FORMAT</span> keyword (as
per
CGATS).<br>
Then shall follow the names of the fields. Standard CGATS field
names
such as:<br>
<br>
<span style="font-weight: bold;"> SAMPLE_ID</span>, <span
style="font-weight: bold;">RGB_R</span>, <span
style="font-weight: bold;">RGB_G</span>, <span
style="font-weight: bold;">RGB_B</span>, <span
style="font-weight: bold;">CMYK_C</span>, <span
style="font-weight: bold;">CMYK_M</span>, <span
style="font-weight: bold;">CMYK_Y</span>, <span
style="font-weight: bold;">CMYK_K</span>, <span
style="font-weight: bold;">XYZ_X</span>, <span
style="font-weight: bold;">XYZ_Y</span>, <span
style="font-weight: bold;">XYZ_Z</span>, <span
style="font-weight: bold;">LAB_L</span>, <span
style="font-weight: bold;">LAB_A</span> or <span
style="font-weight: bold;">LAB_B</span><br>
<br>
shall be used where appropriate. Other device fields shall use the
appropriate pattern, e.g. <span style="font-weight: bold;">CMYKOG_G</span>
etc. Spectral band values shall be named <span style="font-weight:
bold;">SPEC_XXX</span>, where <span style="font-weight: bold;">XXX</span>
is the nearest integer values of
the number of nanometers of the band.<br>
<br>
Optional patch location information shall use the <span
style="font-weight: bold;">SAMPLE_LOC</span> field and shall be of
quoted string type.<br>
<br>
The definition of the fields shall be terminated by the <span
style="font-weight: bold;">END_DATA_FORMAT</span> keyword (as per
CGATS).<br>
<br>
The <span style="font-weight: bold;">NUMBER_OF_SETS</span> keyword
shall have a value that indicates the number of sets of data, e.g. <span
style="font-weight: bold;">1000</span> (as per CGATS).<br>
<br>
The start of the values of the data sets shall be marked by the <span
style="font-weight: bold;">BEGIN_DATA</span> keyword (as per
CGATS).<br>
<br>
Each set of data shall be on one line, and shall be separated by
white
space. All device values shall be percentages (e.g. values from 0.0
to
100.0). XYZ values shall normalized to a Y value of 100.0. L*a*b*
values will have their normal range (L* 0.0 to 100.0, a* and b*
typically -128.0 to 128.0).<br>
<br>
The end of the values of the data sets shall be marked by the <span
style="font-weight: bold;">END_DATA</span> keyword (as per CGATS).<br>
<br>
Generally any other keywords and values will be ignored.<br>
<br>
If a second table is present, and it is a display RAMDAC
calibration,
printers or input devices per channel calibration curves, and will
be
of the <a href="cal_format.html">CAL file format</a>..<br>
<br>
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