File formats that Argyll uses
Argyll uses a number of file formats for its operation, some that
are external standards, and some that are unique to Argyll.
Target Information 1 data. This is an ASCII text, CGATS,
Argyll specific format, used to hold device value ready for creating
a profiling test chart, as well as the estimated CIE color values
for each value, used in laying out the test chart and reading
validation purposes. Additional information on possible spacer and
marking values that may be needed in creating a rendered test chart
is also included. This file is typically created using the targen tool.
Target Information 2 data. This is an ASCII text, CGATS,
Argyll specific format, used to hold device value that have been
laid out in a test chart, together with each test patches location,
and estimated CIE color values for each value used for reading
validation purposes. This file is typically created using the printtarg or
Target Information 3 data. 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,
txt2ti3. See TI3 file format for more detail.
Device calibration information. This is ASCII text, CGATS, Argyll specific format,
used to hold a description of device setup information that brings
it to a desired calibration state. Created by dispcal, printcal,
synthcal. See CAL file format for more detail.
Test chart recognition file. This is ASCII text Argyll specific
format, used to hold a description of a test chart, so that a raster
image of the chart can be turned into device test values by the scanin tool. .cht files are created manually (usually in
combination with scanin creating a
boilerplate file containing the recognition parameters, but not the
patch location information), or by the
printtarg tool, when creating a test print chart that will be
scanned in, rather than read by an instrument. See CHT file format for more detail.
Gamut surface description. This is an ASCII text, CGATS, Argyll specific format,
used to hold a 3 Dimensional surface description of a color gamut.
Typical this is created using the iccgamut,
tiffgamut, or mpplu
tools. The resulting file is typically viewed using the viewgam tool to convert one or more gamuts
into a VRML file, or as input to collink, to describe a source colorspace
Spectral illuminant description. This is an ASCII text, CGATS, Argyll specific format,
used to hold a spectral description of an illuminant. Typically it
is used to record a custom illuminant, for use in
computing Fluorescent Whitening Agent compensation for
reflective samples, as well as computing CIE tristimulus values from
Colorimeter Correction Matrix. This is an ASCII text, CGATS, Argyll specific format,
used to hold a 3x3 correction matrix. The matrix is for a specific
display and Colorimeter, and is used to transform the instruments
XYZ values to make them better match a reference spectrometers
measurements for that display. The file contains a description of
the display, Colorimeter and reference Spectrometer. See ccxxmake for more information.
Colorimeter Calibration Spectral Set. This is an ASCII text, CGATS, Argyll specific format,
used to hold a set of display spectral samples. For Colorimeters
that have known sensor spectral sensitivity information (such as the
i1d3 and Spyder4), this allows a calibration to be created that is
tuned for a particular display. The file contains a description of
the display, the display technology type, the type of spectrometer
used for taking the readings. See oeminst
and ccxxmake for more information.
CGATS.5 Data Exchange Format, from the Annex J, of the ANSI
This is a general purpose ASCII file format suitable for
representing color data, and widely used to store color test values.
Argyll uses this as a base, human readable format, for a variety of
ICC files are files that conform to the International Color
Consortium, File Format for Color profiles. The ICC Profile Format
attempts to provide a cross platform device profile format, that can
be used to translate color data created on one device into another
device's native color space. For a fuller explanation of what the
ICC Profile Format is all about, please refer to http://www.color.org, and the
profile specification. Argyll currently supports profiles that meet
the V3.4 specification. These files are commonly named with a .icm
extension on the Windows platform, .pr or .icc on
the Macintosh and other platforms. As well as device profiles, the
ICC format can also store device link profiles, abstract profiles
and named color profiles. This file is typically created using the colprof or
collink tools. A device link profile is also a way of
specifying a custom ink separation from (say) CMYK to the 6 or more
colorants used by inkjet printers.
Model based device profile format. This is an ASCII text, CGATS, Argyll specific format,
used to hold the parameters to a general model based device profile.
This is a less precise and general format than and ICC profile, but
is a compact way of representing a devices response when it has a
large number of color channels, or when very few measured data
points are available for its construction. This file is typically
created using the mppprof tool.
Tag Image File Format (TIFF), a widely used format within the
graphic arts industries for storing image data. It handles various
forms of compression, and various colorspaces, including RGB, CMYK
and multi-channel files. See http://en.wikipedia.org/wiki/TIFF/.
Argyll makes use of this as a default raster format.
Joint Photographic Experts Group, (JPEG), a widely used format
within the graphic arts and photographic industries for storing
image data. It handles various forms of compression, and various
colorspaces, including RGB and CMYK. See http://en.wikipedia.org/wiki/JPEG/.
Argyll makes use of this as an alternate raster format for some
Virtual Reality Modeling Language file. This is a portable way of
encoding 3 Dimensional objects (such as gamut surfaces). Typically
these can be viewed with a suitable standalone VRML viewer, or a
plug in for a web browser. VRML97 is International Standard ISO/IEC
14772-1:1997. See http://www.vrml.org/
for more information.