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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>fakeread</title>
<meta http-equiv="content-type" content="text/html;
charset=ISO-8859-1">
<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>
readings into CIE XYZ or L*a*b* readings. FWA compensation may be
applied.<br>
<h3>Usage</h3>
<tt><small>spec2cie [options] <span style="font-style: italic;">input.ti3
output.ti3<br>
</span></small></tt><tt><small>-v
Verbose mode</small></tt><br>
<tt><small><small> <a
href="spec2cie.html#I">-I <i>illum</i></a>
Override
actual instrument illuminant
in .ti3 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="colprof.html#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="spec2cie.html#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, S&B
1955_2, shaw, J&V 1978_2<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</span>
Measurement
file<br>
<span style="font-style: italic;">output.ti3</span>
Converted
measurement file</small></tt><br>
<h3>Comments</h3>
This program takes the spectral data in a .ti3 file, converts them
to
XYZ and Lab and fills the XYZ_[XYZ] and LAB_[LAB] columns in the
output
.ti3 file with the computed XYZ and Lab values. If the columns
XYZ_[XYZ] and/or LAB_[LAB] are missing in the input file, they are
added to the output file.<br>
<br>
All other columns are copied from the input to the output .ti3 file.<br>
<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 is 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
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>
<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>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>
<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>
<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
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 spectrums will be shown.<br>
<br>
<br>
<br>
<br>
<br>
<br>
</body>
</html>
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