Description of the .ti3 format
This is an ASCII text, CGATS,
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 chartread, dispread, filmread,
fakeread or one of the conversion tools such as cb2ti3, kodak2ti3,
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 CTI3
is used to avoid confusion with standard ANSI or CGATS files.
The .ti3 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.
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
The first table contains the following:
The file identifier (First 7 characters) shall be CTI3.
A # character introduces a
There may be DESCRIPTOR, ORIGINATOR, or CREATED keywords and values (as
There shall be a DEVICE_CLASS
keyword that has a value of "OUTPUT",
"DISPLAY" or "INPUT".
This indicates to the profile program what type of device the color
information is from.
An "OUTPUT" type device may
have a TOTAL_INK_LIMIT
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.
A "DISPLAY" type device may
have a LUMINANCE_XYZ_CDM2
keyword that contains the absolute XYZ value of white in candelas
per meter squared, e.g. "112.334770
A display device may also have a NORMALIZED_TO_Y_100 keyword that must have a value
of "NO" or "YES", 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 NORMALIZED_TO_Y_100 keyword,
then it can be assumed that the value are 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 LUMINANCE_XYZ_CDM2
Y value and dividing by 100.
There may be a keyword TARGET_INSTRUMENT
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:
"GretagMacbeth i1 Display 1"
"GretagMacbeth i1 Display 2"
"Xrite i1 DisplayPro, ColorMunki Display"
"GretagMacbeth i1 Monitor"
"GretagMacbeth i1 Pro"
"X-Rite i1 Pro 2"
All instruments except the Spectrocam are assumed to have an "A"
type illuminant (incandescent lamp of 2850 degrees Kelvin.)
There may be a INSTRUMENT_TYPE_SPECTRAL
keyword that must have a value of "NO"
or "YES", to indicate
whether the instrument is based on spectral measurement or not.
There may be a DISPLAY_TYPE_REFRESH
keyword that must have a value of "NO"
or "YES", to indicate
whether the instrument was used in a display refresh mode during
There may be keywords with associated values SINGLE_DIM_STEPS, COMP_GREY_STEPS, MULTI_DIM_STEPS or FULL_SPREAD_PATCHES, that
document the composition of the test chart patches.
There shall be a keyword COLOR_REP
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 _ (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 XYZ, or D50
while point L*a*b* space, indicated by LAB. The device spaces shall use the following
Light Light Black 1k
There may be an a previx i
preceeding the device space letter encoding, indicating that
although the space appears to be an additive space, it is in fact a
Typical values might be: "RGB_XYZ"
or "RGB_LAB" for an RGB
display, "iRGB_XYZ" or "iRGB_LAB" for an RGB printer, "CMYK_XYZ" for a printer, "XYZ_RGB" for an RGB scanner.
If spectral values are going to be included in the file, the
following keywords and values shall be used:
contain the number of spectral bands in the readings, e.g. "36".
shall contain the wavelength in nanometers of the first band, e.g. "380.0".
shall contain the wavelength in nanometers of the last band, e.g. "730.0".
keyword shall have a value that indicates the number of fields in
each data set, e.g. 43 (as
The start of the declaration of the fields shall be marked by the BEGIN_DATA_FORMAT keyword (as
Then shall follow the names of the fields. Standard CGATS field
names such as:
SAMPLE_ID, RGB_R, RGB_G, RGB_B, CMYK_C, CMYK_M, CMYK_Y, CMYK_K, XYZ_X, XYZ_Y, XYZ_Z, LAB_L, LAB_A or LAB_B
shall be used where appropriate. Other device fields shall use the
appropriate pattern, e.g. CMYKOG_G
etc. Spectral band values shall be named SPEC_XXX, where XXX
is the nearest integer values of the number of nanometers of the
Optional patch location information shall use the SAMPLE_LOC field and shall be of
quoted string type.
The definition of the fields shall be terminated by the END_DATA_FORMAT keyword (as per
The NUMBER_OF_SETS keyword
shall have a value that indicates the number of sets of data, e.g. 1000 (as per CGATS).
The start of the values of the data sets shall be marked by the BEGIN_DATA keyword (as per
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).
The end of the values of the data sets shall be marked by the END_DATA keyword (as per CGATS).
Generally any other keywords and values will be ignored.
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 CAL file