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<h2><b>spectro/spotread</b></h2>
<h3>Summary</h3>
Use an instrument to read a single color value. This can be a useful
diagnostic aid.<br>
<br>
[ A commercial tool that does much of what spotread does and more,
is the <a href="http://www.argyllpro.com.au/">ArgyllPRO ColorMeter</a>.
]<br>
<h3>Usage Summary</h3>
<small><span style="font-family: monospace;">spotread [-options]
[logfile]</span><br style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#v">-v</a><span
style="font-family: monospace;">
Verbose mode</span><br style="font-family:
monospace;">
<span style="font-family: monospace;"></span><span
style="font-family: monospace;"> </span></small><small><span
style="font-family: monospace;"></span><a style=" font-family:
monospace;" href="#s">-s</a><span style="font-family:
monospace;">
Print spectrum for each reading.</span></small><br
style="font-family: monospace;">
<small><span style="font-family: monospace;"></span><span
style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#S">-S</a><span
style="font-family: monospace;">
Plot the spectrum in a graph window.</span><br
style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#c">-c comport</a><span
style="font-family: monospace;">
Set COM port, 1..4 (default 1)</span><span style="font-family:
monospace;"></span><span style="font-family: monospace;"><br
style="font-family: monospace;">
</span><span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#t">-t</a><span
style="font-family: monospace;">
Use transmission measurement mode</span><br
style="font-family: monospace;">
<span style="font-family: monospace;"> </span><a style="
font-family: monospace;" href="#e">-e</a><span
style="font-family: monospace;">
Use emissive measurement mode (absolute results)<br>
</span></small><small><span style="font-family: monospace;"> </span><a
style=" font-family: monospace;" href="#eb">-eb</a><span
style="font-family: monospace;">
Use display white brightness relative measurement mode<br>
</span></small><small><span style="font-family: monospace;"> </span><a
style=" font-family: monospace;" href="#ew">-ew</a><span
style="font-family: monospace;">
Use display white point relative chromatically adjusted mode<br>
</span></small><small><span style="font-family: monospace;"> </span><a
style=" font-family: monospace;" href="#p">-p</a><span
style="font-family: monospace;">
Use telephoto measurement mode (absolute results)<br>
</span></small><small><span style="font-family: monospace;"> </span><a
style=" font-family: monospace;" href="#pb">-pb</a><span
style="font-family: monospace;">
Use </span></small><small><span style="font-family: monospace;">projector</span></small><small><span
style="font-family: monospace;"> white brightness relative
measurement mode<br>
</span></small><small><span style="font-family: monospace;"> </span><a
style=" font-family: monospace;" href="#pw">-pw</a><span
style="font-family: monospace;">
Use </span></small><small><span style="font-family: monospace;">projector</span></small><small><span
style="font-family: monospace;"> </span></small><small><span
style="font-family: monospace;">white point relative
chromatically adjusted mode</span></small><br>
<small><span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#a">-a</a><span
style="font-family: monospace;">
Use ambient measurement mode (absolute results)<br>
<a href="#f">-f</a>
Use ambient flash measurement mode (absolute results)<br>
</span></small><font size="-1"><span style="font-family:
monospace;"> <a href="#y">-y X</a>
Display type - instrument specific list to choose from.</span></font><br>
<small><span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="spotread.html#I">-I illum</a><span
style="font-family: monospace;">
Set simulated instrument illumination
using FWA (def -i illum):</span><br style="font-family:
monospace;">
<span style="font-family: monospace;">
M0,
M1, M2, A, D50 (def.), D50M2, D65, F5, F8, F10 or file.sp</span></small><br
style="font-family: monospace;">
<small><span style="font-family: monospace;"></span><span
style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#i">-i illum</a><span
style="font-family: monospace;">
Choose illuminant for computation of
CIE XYZ from spectral reflectance & FWA:</span><br
style="font-family: monospace;">
<span style="font-family: monospace;">
A,
D50
(def.),
D50M2, D65, F5, F8, F10 or file.sp</span><br style="font-family:
monospace;">
<span style="font-family: monospace;"> </span><a style="
font-family: monospace;" href="#Q">-Q observ</a><span
style="font-family: monospace;">
Choose CIE Observer for
spectral data or CCSS instrument:</span><br style="font-family:
monospace;">
<span style="font-family: monospace;">
</span></small><small><span
style="font-family: monospace;">1931_2 </span></small><small><span
style="font-family: monospace;"> (def.)</span></small><small><span
style="font-family: monospace;">, 1964_10, S&B 1955_2, shaw,
J&V 1978_2</span></small><small><span style="font-family:
monospace;"></span></small><font size="-1"><span
style="font-family: monospace;"><br>
<a href="#F">-F filter</a>
Set filter configuration:<br>
n
None<br>
p
Polarising filter<br>
6
D65<br>
u
U.V. Cut<br>
<a href="#E">-E extrafilterfile</a>
Apply extra filter compensation file<br>
<a href="#A">-A N|A|X|G</a>
XRGA conversion (default N)<br>
</span></font><font size="-1"><span style="font-family:
monospace;"> <a href="#x">-x</a>
Display Yxy instead of Lab<br>
</span></font><font size="-1"><span style="font-family:
monospace;"> <a href="#h">-h</a>
Display LCh instead of Lab</span></font><br>
<font size="-1"><span style="font-family: monospace;"> <a
href="#V">-V</a>
Show running average and std. devation from ref.</span></font><br>
<font size="-1"><span style="font-family: monospace;"> <a
href="#T">-T</a>
Display correlated color temperatures, CRI and TLCI<br>
</span></font><font size="-1"><span style="font-family:
monospace;"> <a href="#N">-N</a>
Disable initial calibration of instrument if possible</span></font><br>
<font size="-1"><span style="font-family: monospace;"> <a
href="spotread.html#O">-O</a>
Do one cal. or measure and exit</span></font><br>
<font size="-1"><span style="font-family: monospace;"> </span><a
style="font-family: monospace;" href="#H">-H</a><span
style="font-family: monospace;">
Use high resolution spectrum mode
(if available)<br>
<a href="#R">-R fname.sp</a>
Preset reference to spectrum<br>
</span></font><font size="-1"><span style="font-family:
monospace;"><a href="#X1">-X file.ccmx</a>
Apply Colorimeter Correction Matrix</span></font><br>
<span style="font-family: monospace;"> <a href="#X2">-X
file.ccss</a>
Use
Colorimeter
Calibration
Spectral
Samples
for calibration</span><br>
<font size="-1"><span style="font-family: monospace;"> </span><a
style=" font-family: monospace;" href="#Yrn">-<font size="-1">Y</font>
r|n</a><span style="font-family: monospace;">
Override refresh, non-refresh display
mode</span></font><br>
<tt> <a href="#YR">-Y R:<i>rate</i></a>
Override measured refresh rate with rate Hz</tt><br>
<font size="-1"><span style="font-family: monospace;"> </span><a
style=" font-family: monospace;" href="#YA">-<font size="-1">Y </font>A</a><span
style="font-family: monospace;">
Use non-adaptive integration time mode (if
available).</span></font><br>
<tt> <a href="#YW">-Y W:fname.sp</a>
Save white tile ref. spectrum to file</tt><br>
<tt> <a href="#YL">-Y L</a>
Test for i1Pro Lamp
Drift, and remediate it</tt><br>
<font size="-1"><span style="font-family: monospace;"> <a
href="#W">-W n|h|x</a>
Override
serial
port
flow
control:
n
=
none,
h = HW, x = Xon/Xoff</span></font><br>
<small><span style="font-family: monospace;"> </span><a style="
font-family: monospace;" href="#D">-D [level]</a><span
style="font-family: monospace;">
Print debug diagnostics to stderr</span></small><br>
<font size="-1"><span style="font-family: monospace;"> <a
href="#log"><span style="font-style: italic;">logfile</span></a>
Optional file to save reading results<br style="font-family:
monospace;">
</span></font><small><span style="font-family: monospace;"></span><span
style="font-family: monospace;"></span></small><br>
<h3>Usage Details and Discussion</h3>
<b>spotread</b> operates in a similar fashion to <a
href="chartread.html"> chartread</a>, but allows the reading of a
succession of single color values. This can be useful in diagnosing
issues with profile creation and operation.<br>
<br>
<a name="v"></a>The <b>-v</b> flag causes extra information to be
printed out during chartread operation.<br>
<br>
<a name="s"></a>The <b>-s</b> flag enables the printing out
spectral reflectance/transmittance values, if the instrument
supports this.<br>
<br>
<a name="S"></a>The <b>-S</b> flag enables the plotting of the
spectral reflectance/transmittance values, if the instrument
supports this. If a reference is taken, this will be plotted in red.
You must strike a key in the plot window to continue with another
measurement.<br>
<br>
The Graph plots light wavelength on the X axis, and either absolute
or relative level on the Y axis. <br>
<br>
<table border="1" cellpadding="0" cellspacing="0" width="200"
height="153">
</table>
<table border="1" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<th valign="top"> Measurement Mode <br>
</th>
<th valign="top">Y Units<br>
</th>
</tr>
<tr>
<td valign="top" align="center">Emission<br>
</td>
<td valign="top" align="center">mW/(m<sup>2</sup>.sr.nm)</td>
</tr>
<tr>
<td valign="top" align="center">Ambient<br>
</td>
<td valign="top" align="center">mW/(m<sup>2</sup>.nm)<br>
</td>
</tr>
<tr>
<td valign="top" align="center">Emission Flash<br>
</td>
<td valign="top" align="center"> mW/(m<sup>2</sup>.sr.nm.s)
<br>
</td>
</tr>
<tr>
<td valign="top" align="center">Ambient Flash<br>
</td>
<td valign="top" align="center">mW/(m<sup>2</sup>.nm.s)<br>
</td>
</tr>
<tr>
<td valign="top" align="center">Reflective<br>
</td>
<td valign="top" align="center">%/nm<br>
</td>
</tr>
<tr>
<td valign="top" align="center">Transmissive<br>
</td>
<td valign="top" align="center">%/nm<br>
</td>
</tr>
</tbody>
</table>
<br>
<a name="c"></a> The instrument is assumed to communicate through a
USB or serial communication port, and the port can be selected with
the <b>-c</b> option, if the instrument is not connected to the
first port. If you invoke <span style="font-weight: bold;">spotread</span>
so as to display the usage information (i.e. "spotread -?" or
"spotread --"), then the discovered USB and serial ports will be
listed. On UNIX/Linux, a list of all possible serial ports are
shown, but not all of them may actually be present on your system.<br>
<br>
<a name="t"></a>If using an Xrite DTP41T or SpectroScanT, and
printing onto transparent or back lit media, use the <b>-t</b> flag
to operate the instrument in transparency mode. If using the
Spectroscan, this triggers a fake transparency mode, that uses a
separate backlight (such as a light box). The instrument will
be used to calibrate the level of backlight, and use this to compute
the transparency of the test chart samples. Note that for good
transparency values, the backlight level needs to be neither too
bright not too dark, should ideally be incandescent rather than
fluorescent (since fluorescent lights often have big dips in their
spectrum), and ideally should be of uniform brightness over the
measurement area.<br>
<br>
<a name="e"></a>The <span style="font-weight: bold;">-e</span> flag
allows measuring in emission mode (e.g. displays or illuminants)
using instruments that support this mode. An adaptive integration
time will be used in devices that support it by default (see the <a
href="#ZA">-ZA</a> flag). Values returned are absolute.<br>
<br>
<a name="eb"></a>The <span style="font-weight: bold;">-eb</span>
flag allows measuring in emission mode using instruments that
support this mode, with the brightness reading being relative to the
white value read as the first reading. While the brightness values
are then relative to the white, the readings are otherwise absolute.
This corresponds to the raw ICC absolute readings created by <a
href="dispread.html">spotread</a>.<br>
<br>
<a name="ew"></a>The <span style="font-weight: bold;">-ew</span>
flag allows measuring in emissive mode using instruments that
support this mode, with the reading being relative to the white
value read as the first reading using a Bradford chromatic adaption.
This matches the absolute <-> relative intent transformation
of Argyll ICC profiles.<br>
<br>
<a name="p"></a>The <span style="font-weight: bold;">-p</span> flag
allows measuring in telephoto mode, using instruments that support
this mode, e.g. the ColorMunki. Values returned are absolute.<br>
Note that you would use normal emissive mode to measure
projectors using instruments without a specific telephoto mode.<br>
<br>
<a name="pb"></a>The <span style="font-weight: bold;">-pb</span>
flag allows measuring in telephoto mode using instruments that
support this mode, with the brightness reading being relative to the
white value read as the first reading. While the brightness values
are then relative to the white, the readings are otherwise absolute.
This corresponds to the raw ICC absolute readings created by <a
href="dispread.html">spotread</a>.<br>
<br>
<a name="pw"></a>The <span style="font-weight: bold;">-pw</span>
flag allows measuring in telephoto mode using instruments that
support this mode, with the reading being relative to the white
value read as the first reading using a Bradford chromatic adaption.
This matches the absolute <-> relative intent transformation
of Argyll ICC profiles.<br>
<br>
<a name="a"></a>The <span style="font-weight: bold;">-a</span> flag
allows measuring in ambient illumination mode using instruments that
support this mode (i.e. Eye-One Display 2). Values returned are
absolute, and include the various color temperatures and Color
Rendering Index (<a href="#T">see <span style="font-weight: bold;">-T</span></a>).
If the instrument does not support ambient mode, emissive mode will
be used instead. An adaptive integration time will be used in
devices that support it. <br>
<br>
For an instrument that supports it (i.e. the Emulated transmission
measurement mode of the JETI 1211), then using <b>-a</b> after the
<b>-t</b> switch will select the alternate 90/diffuse transmission
geometry (i.e. using the ambient adapter for transmission
measurement).<br>
<br>
<a name="f"></a>The <span style="font-weight: bold;">-f</span> flag
allows measuring a flash with those instruments that support
scanning emissive measurements. The instrument needs to be triggered
by holding down its button, triggering the flash, then releasing the
button, similar to how a reflective strip is read.<br>
<br>
<a name="y"></a> The <span style="font-weight: bold;">-y</span>
flag allows setting the Display Type. The selection typically
determines two aspects of of the instrument operation: <span
style="font-weight: bold;">1)</span> It may set the measuring mode
to suite <a
href="http://en.wikipedia.org/wiki/Comparison_of_display_technology"><span
style="font-weight: bold;">refresh</span> or <span
style="font-weight: bold;">non-refresh</span> displays</a>.
Typically only LCD (Liquid Crystal) displays have a non-refresh
nature. <span style="font-weight: bold;">2)</span> It may select an
instrument calibration matrix suitable for a particular display
type. The selections available depends on the type and model of
instrument, and a list of the options for the discovered instruments
will be shown in the <a href="ArgyllDoc.html#CmdLine">usage</a>
information. For more details on what particular instruments support
and how this works, see <a href="instruments.html">Operation of
particular instruments</a>. <b>3)</b> Any installed CCSS files
(if applicable), or CCMX files. These files are typically created
using <a href="ccxxmake.html">ccxxmake</a>, and installed using <a
href="oeminst.html">oeminst</a>. The default and Base Calibration
types will be indicated in the usage.<br>
<br>
<a name="I"></a>The <b>-I</b> parameter allows specifying a
standard or custom illumination spectrum to be used as the simulated
reflectance instrument illuminant when FWA compensation is used
during <u>measurement</u>, overriding the default <b>D50</b> or
CIE computation illuminant used for FWA (see <b>-i</b> below<b>). </b>If
intending to use standard <b>M0</b>, <b>M1</b> or <b>M2</b>
conditions, then use just the <b>-I</b> option and not the <b>-i</b>
option. 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 reflectance illumination spectrum applied to <span
style="text-decoration: underline;">reflective</span> or <u>transmissive</u>
spectral data to <u>compute</u> CIE tristimulus values. <b>A</b>,
<b>D50</b>, <b>D50M2, 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 using <b>-I</b> to obtain standard <b>M0</b>,
<b>M1</b> or <b>M2</b> conditions, then this <b>-i</b> option is <b>not</b>
normally used. If a filename is specified instead, it will be
assumed to be an Argyll specific <a href="File_Formats.html#.sp">.sp</a>
spectrum file. If FWA compensation is used during measurement, this
illuminant will be used by default as the simulated instrument
illuminant.<br>
<br>
<a name="Q"></a> The <b>-Q</b> flag allows specifying a tristimulus
observer, and is used to compute PCS (Profile Connection Space)
tristimulus values. This is possible for a spectral instrument, or a
colorimeter that has CCSS capability. 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>
<a name="F"></a>The <b>-F</b> options allows configuring the
instrument to have a particular filter fitted to it. Some
instruments (i.e. the Gretag Spectrolino) allow the fitting of
various filters, such as a polarizing filter, D65 illuminant
simulation, or Ultra Violet Cut filter, and this option allows the
instrument to be configured appropriately.<br>
<br>
<a name="E"></a>The <b>-E</b> option allows the setting of an extra
filter compensation file, that allows for the filtration of the
spectral readings through a medium of some kind, when in emission
mode. This is useful in allowing for such things as telescopic
adapters that use a glass of acrylic lens in the optical path. [<span
style="font-weight: bold;">Note</span> that this is currently only
supported by the Spectrolino driver.]<br>
<br>
<a name="A"></a>The <b>-A</b> options allows overriding the default
or environment variable set <a href="XRGA.html">XRGA</a>
conversion:<br>
<br>
<b>-A N|A|X|G</b><br>
<br>
The <b>N</b> argument sets
the calibration to Native (default).<br>
The <b>A</b> argument sets
the calibration to XRGA.<br>
The <b>X</b> argument sets
the calibration to XRDI.<br>
The <b>G</b> argument sets
the calibration to GMDI.<br>
<br>
<a name="x"></a>The <b>-x</b> option causes the reading to be
displayed as XYZ and Yxy values, rather than the default XYZ and
L*a*b*<br>
<br>
<a name="h"></a>The <b>-h</b> option causes the reading to be
displayed as XYZ and LCh values, rather than the default XYZ and
L*a*b*<br>
<br>
<a name="V"></a>The <b>-V</b> enables average and standard
deviation statistics on the XYZ and L*a*b* values. This start and is
reset whenever a reference is taken ('r' key). A side effect of this
option is to disable the clamping of XYZ and L*a*b* value to
positive, so that a valid average of black can be obtained.This is
useful in quantifying repeatability.<br>
<br>
<a name="T"></a>The <b>-T</b> option causes various color
temperatures to be displayed, plus the Color Rendering Index. Three
color temperatures will be shown. The first is the classic
Correlated Color Temperature, which is the black body (Plankian)
color closest to the measured color in the CIE 1960 UCS color space.
The second is the black body (Plankian) color that has a minimum
CIEDE2000 error to the measured color. The last is the daylight
color that has a minimum CIEDE2000 error to the measured color. The
delta E between the closest temperature and the measured color is
also shown for each. The Color Rendering Index (CRI Ra) including
the R9 value, plus the TLCI (Qa) is also computed if the instrument
is capable of spectral measurement. If the notation <span
style="font-weight: bold;">(Invalid)</span> is displayed after the
CRI or TLCI, then this means that the the spectrum white point is to
far from the black body and Daylight locus to be meaningful.<br>
<br>
<a name="N"></a> <span style="font-weight: bold;">-N</span> Any
instrument that requires regular calibration will ask for
calibration on initial start-up. Sometimes this can be awkward if
the instrument is being mounted in some sort of measuring jig, or
annoying if several sets of readings are being taken in quick
succession. The -<span style="font-weight: bold;">N</span>
suppresses this initial calibration if a valid and not timed out
previous calibration is recorded in the instrument or on the host
computer. It is advisable to only use this option on the second and
subsequent measurements in a single session.<br>
<br>
<a name="O"></a><b>-O</b> Do a calibration or a single measurement
and exit. To take a measurement with an instrument that always does
a calibration first, calibrate it and then use -O with -N. The -O
option is intended to simplify scripted use of spotread.<br>
<br>
<a name="H"></a> The -<span style="font-weight: bold;">H</span>
option turns on high resolution spectral mode, if the instrument
supports it. See <a href="instruments.html">Operation of particular
instruments</a> for more details.<br>
<br>
<a name="R"></a><font size="-1">The <b>-R <i>fname.sp</i></b>
option allows specifying a reference spectrum</font> to preset the
reference values used to calculate delta E etc. This can be useful
in checking against a previously saved value (<b>'s' </b>command),
or in checking the instruments consistency against it's <a
href="#YW">reflective white reference spectrum</a>.<br>
<br>
<a name="X1"></a> The -<span style="font-weight: bold;">X <span
style="font-style: italic;">file.ccmx</span></span> option reads
a <a href="File_Formats.html#.ccmx">Colorimeter Correction Matrix</a>
from the given file, and applies it to the colorimeter instruments
readings. This can improve a colorimeters accuracy for a particular
type of display. A list of contributed <span style="font-weight:
bold;">ccmx</span> files is <a href="ccmxs.html">here</a>.<br>
<br>
<a name="X2"></a> The -<span style="font-weight: bold;">X <span
style="font-style: italic;">file.ccss</span></span> option reads
a <a href="File_Formats.html#.ccss">Colorimeter Calibration
Spectral Sample</a> from the given file, and uses it to set the
colorimeter instruments calibration. This will only work with
colorimeters that rely on sensor spectral sensitivity calibration
information (ie. the X-Rite <span style="font-weight: bold;">i1d3</span>,
or the DataColor <span style="font-weight: bold;">Spyder4 &
Spyder5</span>).This can improve a colorimeters accuracy for a
particular type of display.<br>
<br>
<a name="Yrn"></a> The -<span style="font-weight: bold;">Y r </span>and
<b>-Y n</b> options overrides the refresh display mode set by the <a
href="#y">-y display type selection</a>, with <b>-Y</b><span
style="font-weight: bold;"> r</span> forcing refresh display mode,
and <b>-Y n</b> forcing a non-refresh display mode. Not all
instruments support a display measurement refresh mode, or the
ability to override the mode set by the display type selection.<br>
<br>
<a name="YR"></a> The -<span style="font-weight: bold;">Y R:<i>rate</i></span><b></b>
options overrides calibration of the instrument refresh rate. This
may be useful if the instrument supports this function and the
refresh rate cannot be accurately calibrated from the display
itself.<br>
<br>
<a name="YA"></a> The -<span style="font-weight: bold;">Y A</span>
option uses a non-adaptive integration time emission measurement
mode, if the instrument supports it, such as the Eye-One Pro,
ColorMunki, i1d3 or K10. By default an adaptive integration time
measurement mode will be used for emission measurements, but some
instruments support a fixed integration time mode that can be used
with display devices. This may give faster measurement times, but
may also give less accurate low level readings.<br>
<br>
<a name="W"></a>The <b>-W</b> <span style="font-weight: bold;">n|h|x</span>
parameter overrides the default serial communications flow control
setting. The value <span style="font-weight: bold;">n</span> turns
all flow control off, <span style="font-weight: bold;">h</span>
sets hardware handshaking, and <span style="font-weight: bold;">x</span>
sets Xon/Xoff handshaking. This commend may be useful in workaround
serial communications issues with some systems and cables. <br>
<br>
<a name="YW"></a>The <b>-Y W:<i>fname.s</i>p</b> option allows
saving an instruments reference white tile reflectance spectrum to a
file. Reflective instruments use a white reference tile to calibrate
against, and typically the spectral reflectance of the white tile is
recorded inside the instrument to calibrate to. The saved spectrum
can be used to compare against the measurements of a reference grade
measurement of the white tile to check for tile deterioration, or
can be used as a reference for checking on instrument calibration
accuracy or consistency (See the <a href="#R">-R option</a>). Not
all instruments support this option (Currently the Spectrolino,
i1Pro, i1Pro2 and ColorMunki spectrometer.)<br>
<br>
<a name="YL"></a> The <b>-Y l|L</b> option is a special function
for X-Rite <a href="instruments.html#i1p2">i1Pro</a> instruments.
These instruments use an incandescent lamp as a light source for
reflectance measurement, and some instruments after some patterns of
use, can suffer from Lamp output thermal drift, due to the build up
of filament tungsten on the bulb inner surface. This function first
measures the Lamp drift, and then if the <b>-Y L</b> version is
used and the drift is greater than normal (0.06 - 0.1 Delta E), it
will attempt to remediate the problem by turning the lamp on for
some seconds so that it reaches normal operating temperature and is
able to re-circulate the tungsten back onto the filament properly.
It will then wait for the lamp to cool, and re-measure the drift.
These operations can take a few minutes, and it is advisable to let
the instrument cool off further after this operation, for 2 - 5
minutes, to allow it to return to normal operation conditions.<br>
<br>
The remediation function should be used infrequently or if the
repeatability of the instrument seems to be poorer than usual, as
frequent use may consume lamp life unnecessarily. If the lamp is
nearing its end of life, this function may not be effecive.<br>
<br>
<a name="D"></a>The <b>-D</b> flag causes communications and other
instrument diagnostics to be printed to stdout. A level can be set
between 1 .. 9, that may give progressively more verbose
information, depending on the instrument. This can be useful in
tracking down why an instrument can't connect.<br>
<br>
<a name="log"></a>The <span style="font-weight: bold; font-style:
italic;">logfile</span> is an optional file that can be specified
to capture each reading taken. There will be column headers printed
to the first row, and then each reading will be on a separate line
with tab separators.<br>
<br>
All instruments will be used in a spot mode. For the SpectroScan
instrument, the samples can be placed on the table, and the
measuring head positioned before taking a measurement. Note that the
default mode (reflectance measurement) may not be supported by the
instrument, so a mode it does support will be selected
automatically. Override this on the command line if desired. Note
that the DTP51, DTP92, DTP94 and Eye-One Display are colorimeters,
and cannot read spectral information, and that the DTP92 can only
read CRT type displays.<br>
<br>
<hr style="width: 100%; height: 2px;"><br>
Once <b>spotread</b> has established communications with the
instrument, it awaits a command from the user, indicated by the user
hitting a key or activating the instrument switch. XYZ values are in
the range 0 .. 100 for reflective or transmissive readings, and
absolute cd/m^2 for display, emissive and ambient readings.<br>
<br>
By default the L*a*b* values are computed relative to a fixed D50
100 scale white point, so values for emissive sources are not
particularly useful.<br>
Using the display white relative mode uses a Bradford chromatic
transform to transform from the measured white to a D50 white (the
same as ArgyllCMS ICC profile deals a display white), and then
computes the D50 L*a*b from that.<br>
<br>
If Fluorescent Whiter Additive (FWA) compensated readings are to be
made, then this needs to be enabled with the correct command line
switches, and then setup for each paper white background color, to
establish an FWA reference. There is one FWA reference locations
available for each alphabetic character not used for a special
function (ie. not <span style="font-weight: bold;">H, K, N, Q, R,
S, F)</span>, keyed to the capital letters <b>A-</b><b>Z</b>,
allowing FWA corrected comparisons between many different media.<br>
<br>
Once a particular reference location is initialized with the FWA
paper color, subsequent readings triggered by using the
corresponding lower case letter <span style="font-weight: bold;">a-z</span>
will use FWA compensation for that keyed location. Note that
readings that are triggered some other way (ie. using a non
alphabetic key, or using the instrument switch) will not be FWA
corrected readings.<br>
<br>
If a non-FWA readings is to be performed, then a reading for a
location that has not been initialised for paper white should be
used, or a non alphabetic key (such as space or return) or
instrument switch trigger should be used.<br>
<br>
If the instrument supports a high resolution spectral mode, then it
can be toggled on and off using the <span style="font-weight:
bold;">h</span> key.<br>
<br>
If the instrument supports a laser target (such as the JETI
specbos), then this can be toggled on & off using the <b>t</b>
key. It will automatically be turned off at each measurement.<br>
<br>
If the instrument supports stored readings (ie. DTP20), then these
can be ignored using the <span style="font-weight: bold;">n</span>
key.<br>
<br>
The previous reading can be stored as a reference, and delta E's
computed for each reading, using the <b>r</b> key.<br>
<br>
A previous spectral reading can be saved in a spectrum CGATS file
(spectrum.sp) using the <span style="font-weight: bold;">s</span>
key, making this a convenient way of creating a custom illuminant
spectrum.<br>
<br>
A calibration can be initiated using the <span style="font-weight:
bold;">k</span> key.<br>
<br>
For instruments that support it and are in a refresh display mode,
the calibrated refresh rate can be read back using the <b>f</b>
key.<br>
<br>
For instruments that support it and are in an emissive measurement
mode, a display refresh rate measurement can be made by using the <b>F</b>
key.<br>
<br>
<br>
<br>
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core-release
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