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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>spec2cie</title>
<meta http-equiv="content-type" content="text/html;
charset=windows-1252">
<meta name="author" content="Graeme Gill">
</head>
<body>
<h2><b>spectro/</b><span style="text-decoration: underline;"></span>spec2cie</h2>
<h3>Summary</h3>
Convert spectral <a href="File_Formats.html#.ti3">.ti3</a> or <a
href="File_Formats.html#.sp">.sp</a> readings into CIE XYZ and D50
L*a*b* readings. Apply FWA, plot spectrums. Convert to/from XRGA
standard.<br>
This is assumed to be for a reflective media by default - i.e. that
the input .ti3 or .sp file values are spectral reflectances, unless
the input is marked as <span style="font-weight: bold;">DEVICE_CLASS</span>
<span style="font-weight: bold;">EMISINPUT</span> (See the <a
href="ti3_format.html">description of the .ti3 format</a>. This
would have to be done manually, as no ArgyllCMS tools generate such
data.)<br>
<h3>Usage</h3>
<tt><small>spec2cie [options] <span style="font-style: italic;">input.[ti3|sp]
output.[ti3|sp]<br>
</span></small></tt><tt><small>-v
Verbose mode<br>
<a href="A">-A NN|AX|AG|XA|XG|GA|GX</a> XRGA
conversion (default NN)<br>
</small></tt> <tt><small><small> <a href="#I">-I <i>illum</i></a>
Override actual instrument illuminant in .ti3 or .sp file:<br>
A, C, D50, D50M2, D65, F5, F8, F10 or file.sp<br>
(only used in conjunction
with <span style="font-weight: bold;">-f</span>)<br>
</small></small></tt><tt><small><small> <a href="#f">-f [<i>illum</i>]</a>
Use Fluorescent Whitening Agent compensation [simulated inst.
illum.:<br>
M0, M1, M2, A, C, D50 (def.),
D50M2, D65, F5, F8, F10 or file.sp]<br>
</small></small></tt><tt><small><small><small> <a href="#i">-i
<i>illum</i></a>
Choose illuminant for computation of CIE XYZ from spectral
data & FWA:<br>
A, C, D50 (def.), D50M2, D65, F5, F8, F10 or file.sp<br>
</small></small><a href="#o">-o <i>observ</i></a>
Choose CIE Observer for spectral data:<br>
1931_2 </small></tt><tt><small>
(def.)</small></tt><tt><small>, 1964_10, </small></tt><tt><small><tt><small>2012_2,
2012_10, </small></tt>S&B 1955_2, shaw, J&V 1978_2
or file.cmf<br>
<a href="#p">-n</a>
Don't
output
spectral values<br>
</small></tt><tt><small> <a href="#p">-p</a>
Plot each values spectrum</small></tt><tt><br>
</tt><tt> </tt><tt><small> <span style="font-style: italic;">input.[ti3|sp]</span>
Measurement file<br>
<span style="font-style: italic;">output.[ti3</span>|sp]
Converted
measurement file</small></tt><br>
<h3>Comments</h3>
This program takes the (usually reflective) spectral data in a .ti3
or .sp file, converts them to XYZ and D50 L*a*b* and fills the
XYZ_[XYZ] and LAB_[LAB] columns in the output .ti3 or .sp file. If
the columns XYZ_[XYZ] and/or LAB_[LAB] are missing in the input
file, they are added to the output file.<br>
<br>
If FWA correction is applied, then the spectra saved will be FWA
corrected, as well as the XYZ and D50 L*a*b* values.<br>
<br>
All other columns are copied from the input to the output .ti3 or
.sp file.<br>
<br>
Setting an actual instrument/simulated instrument/CIE illuminant
only has an effect for reflective/transmissive spectra. Emissive
spectra don't have an illuminant, and will simply be converted to
XYZ using the given observer. <br>
<br>
<a name="A"></a>The <b>-A</b> parameter allows specifying a
conversion between the <a href="XRGA.html">XRGA</a> measurement
standards:<br>
<br>
The <b>NN</b> argument
disabled any conversion.<br>
The <b>AX</b> argument
converts from XRGA to XRDI<br>
The <b>AG</b> argument
converts from XRGA to GMDI<br>
The <b>XA</b> argument
converts from XRDI to XRGA<br>
The <b>XG</b> argument
converts from XRDI to GMDI<br>
The <b>GA</b> argument
converts from GMDI to XRGA<br>
The <b>GX</b> argument
converts from GMDI to XRDI<br>
<br>
A warning will be issued if the "from" setting doesn't match that
contained in the .ti3 file.<br>
<br>
(XRGA = Modern X-Rite, XRDI = Historical X-Rite, GMD = Historical
GretagMacbeth).<br>
<br>
<a name="I"></a>The <b>-I</b> parameter allows specifying a an
illumination spectrum for the actual instrument illuminant,
overriding that computed from the type of instrument (recorded in
the .ti3 file). This is rarely used. This parameter can only be used
in combination with the <span style="font-weight: bold;">-f</span>
flag. If a filename is specified instead, it will be assumed to be
an Argyll specific <a href="File_Formats.html#.sp">.sp</a> custom
spectrum file. Illuminant details are:<br>
<br>
A CIE
tungsten filament lamp 2848K<br>
D50 CIE daylight 5000K<br>
D65 CIE daylight 6500K<br>
F5 CIE Fluorescent
6350K, CRI 72<br>
F8 CIE Fluorescent
5000K, CRI 95<br>
F10 CIE Fluorescent
5000K, CRI 81<br>
<br>
<br>
<a name="f"></a> The <b>-f</b> flag enables Fluorescent Whitening
Agent (FWA) compensation. This only works if spectral data is
available and, the instrument is not UV filtered. FWA
compensation adjusts the spectral samples so that they appear to
have been measured using an illuminant that has a different level of
Ultra Violet to the one the instrument actually used in the
measurement. The optional illumination parameter allows specifying a
standard or custom illumination spectrum to be used as the similated
instrument illuminant, overriding the default <b>D50</b> or CIE
computation illuminant used for FWA (see <b>-i</b> below<b>). </b>See
<a href="colprof.html#f">colprof -f</a> for a fuller explanation. <br>
<br>
<a name="i"></a>The <b>-i</b> parameter allows specifying a
standard or custom illumination spectrum, applied to spectral .ti3
pr .sp data to compute PCS (Profile Connection Space) tristimulus
values. <b>A</b>, <b>D50</b>, <b>D65</b>, <b>F5</b>, <b>F8</b>,
<b>F10</b> are a selection of standard illuminant spectrums, with <b>D50</b>
being the default. If a filename is specified instead, it will be
assumed to be an Argyll specific <a href="File_Formats.html#.sp">.sp</a>
custom spectrum file. This only works if spectral data is available.
Illuminant details are:<br>
<br>
A CIE
tungsten filament lamp 2848K<br>
D50 CIE daylight 5000K<br>
D65 CIE daylight 6500K<br>
F5 CIE Fluorescent
6350K, CRI 72<br>
F8 CIE Fluorescent
5000K, CRI 95<br>
F10 CIE Fluorescent
5000K, CRI 81<br>
<br>
Custom illuminants are most often used when a viewing booth or
other known viewing conditions is going to be used to view results.
Other illuminant reference files could be created using a suitable
measuring instrument such as a spectrolino, or an eyeone using <a
href="spotread.html">spotread</a>, although such instruments do
not themselves provide the necessary response down to Ultra Violet
that is needed for accurate operation of Fluorescent Whitening Agent
compensation. The best way of measuring a custom illuminant is to
use <a href="illumread.html">illumread</a>, since it uses a special
method to estimate the illuminant UV in a way that complements FWA
compensation. (See the discussion above for the <b>-f</b> flag).<br>
<br>
Note that if an illuminant other than D50 is chosen, the resulting
ICC profile will not be standard, and may not work perfectly with
other profiles that that use the standard ICC D50 illuminant,
particularly if the absolute rendering intent is used. Profiles
should generally be linked with other profiles that have the same
illuminant and observer.<br>
<br>
If a non D50 illuminant is used, then an extra set of L*a*b* output
fields will be created in the resulting CGATS file, containing
values relative to the illuminant white point. These will be
labelled XXXLAB_L etc, where XXX is the name of the illuminant.
These are informational only, and are not used by any ArgyllCMS
tools.<br>
<br>
<a name="o"></a> The <b>-o</b> flag allows specifying a tristimulus
observer, and is used to compute PCS (Profile Connection Space)
tristimulus values. The following choices are available:<br>
<b> 1931_2</b> selects the standard CIE 1931 2 degree observer
(the default).<br>
<b>1964_10</b> selects the standard CIE 1964 10 degree
observer.<br>
<b> 2012_2</b> selects the proposed CIE 2012 2 degree observer<br>
<b>2012_10</b> selects the proposed CIE 2012 10 degree
observer<br>
<b>1955_2</b> selects the Stiles and Birch 1955 2 degree
observer<br>
<b>1978_2 </b>selects the Judd and Voss 1978 2 degree
observer<br>
<b>shaw</b> selects the Shaw and Fairchild 1997 2 degree
observer<br>
<i><b>file.cmf</b></i> selects an observer specified by the
given <a href="File_Formats.html#.cmf">.cmf</a> file.<br>
<br>
Note that if an observer other than 1931 2 degree is chosen, the
resulting ICC profile will not be standard, and cannot be freely
interchanged with other profiles that that us the standard 1931 2
degree observer. Profiles should only be linked with other profiles
that have the same illuminant and observer.<br>
<br>
<br>
<a name="n"></a>The <span style="font-weight: bold;">-n</span> flag
disables the output of the spectral values. If just the XYZ and D50
L*a*b* values are needed, this makes for a smaller, easier to read
file.<br>
<br>
<a name="p"></a>The <span style="font-weight: bold;">-p</span> flag
causes each spectrum to be plotted. If FWA compensation is used,
then the before/after compensation spectruma will be shown.<br>
<br>
<br>
<br>
<br>
<br>
<br>
</body>
</html>
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