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-<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
-<html>
- <head>
- <title>illumread</title>
- <meta http-equiv="content-type" content="text/html;
- charset=ISO-8859-1">
- <meta name="author" content="Graeme Gill">
- </head>
- <body>
- <h2><b>spectro/illumread</b></h2>
- <h3>Summary</h3>
- Use an instrument or instruments to measure an illuminant spectrum,
- including estimate its Ultra Violet content. A combination of direct
- illumination readings and readings from a piece of paper having some
- FWA content are used for this. (If the UV content is not needed, or
- a suitable instrument is not available, then <a
- href="spotread.html">spotread</a> should be used instead.)<br>
- <h3>Usage Summary</h3>
- <small><span style="font-family: monospace;">illumread [-options]
- illuminant.sp</span><br style="font-family: monospace;">
- <span style="font-family: monospace;">&nbsp;</span><a
- style="font-family: monospace;" href="#v">-v</a><span
+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
+<html>
+ <head>
+ <title>illumread</title>
+ <meta http-equiv="content-type" content="text/html;
+ charset=windows-1252">
+ <meta name="author" content="Graeme Gill">
+ </head>
+ <body>
+ <h2><b>spectro/illumread</b></h2>
+ <h3>Summary</h3>
+ Use an instrument or instruments to measure an illuminant spectrum,
+ including estimate its Ultra Violet content. A combination of direct
+ illumination readings and readings from a piece of paper having some
+ FWA content are used for this. (If the UV content is not needed, or
+ a suitable instrument is not available, then <a
+ href="spotread.html">spotread</a> should be used instead.)<br>
+ <h3>Usage Summary</h3>
+ <small><span style="font-family: monospace;">illumread [-options]
+ illuminant.sp</span><br style="font-family: monospace;">
+ <span style="font-family: monospace;">&nbsp;</span><a
+ style="font-family: monospace;" href="#v">-v</a><span
style="font-family: monospace;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
&nbsp;
- &nbsp; &nbsp; Verbose mode</span><span style="font-family:
- monospace;"></span></small><small><span style="font-family:
- monospace;"></span></small><br style="font-family: monospace;">
- <small><span style="font-family: monospace;"></span><span
- style="font-family: monospace;">&nbsp;</span><a
- style="font-family: monospace;" href="#S">-S</a><span
- style="font-family: monospace;">
- &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
- &nbsp; &nbsp; &nbsp; Plot the readings in a graph window.</span><br
- style="font-family: monospace;">
- <span style="font-family: monospace;">&nbsp;</span><a
- style="font-family: monospace;" href="#c">-c comport</a><span
+
+
+
+ &nbsp; &nbsp; Verbose mode</span><span style="font-family:
+ monospace;"></span></small><small><span style="font-family:
+ monospace;"></span></small><br style="font-family: monospace;">
+ <small><span style="font-family: monospace;"></span><span
+ style="font-family: monospace;">&nbsp;</span><a
+ style="font-family: monospace;" href="#S">-S</a><span
+ style="font-family: monospace;">
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
+ &nbsp; &nbsp; &nbsp; Plot the readings in a graph window.</span><br
+ style="font-family: monospace;">
+ <span style="font-family: monospace;">&nbsp;</span><a
+ style="font-family: monospace;" href="#c">-c comport</a><span
style="font-family: monospace;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
Set
- COM port, 1..4 (default 1)</span><span style="font-family:
- monospace;"></span><span style="font-family: monospace;"></span><span
- style="font-family: monospace;"></span></small><small><span
- style="font-family: monospace;"></span></small><font size="-1"><span
- style="font-family: monospace;"></span></font><font size="-1"><span
- style="font-family: monospace;"><br>
- </span></font><font size="-1"><span style="font-family:
+
+
+
+ COM port, 1..4 (default 1)</span><span style="font-family:
+ monospace;"></span><span style="font-family: monospace;"></span><span
+ style="font-family: monospace;"></span></small><small><span
+ style="font-family: monospace;"></span></small><font size="-1"><span
+ style="font-family: monospace;"></span></font><font size="-1"><span
+ style="font-family: monospace;"><br>
+ </span></font><font size="-1"><span style="font-family:
monospace;">&nbsp;<a href="#N">-N</a>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
Disable
- initial calibration of instrument</span></font> if possible<br>
- <font size="-1"><span style="font-family: monospace;">&nbsp;</span><a
- style="font-family: monospace;" href="#H">-H</a><span
- style="font-family: monospace;">
- &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
- &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Use high resolution spectrum mode
- (if available)<br>
+
+
+
+ initial calibration of instrument</span></font> if possible<br>
+ <font size="-1"><span style="font-family: monospace;">&nbsp;</span><a
+ style="font-family: monospace;" href="#H">-H</a><span
+ style="font-family: monospace;">
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Use high resolution spectrum mode
+ (if available)<br>
<font size="-1">&nbsp;<a href="#Yr">-Y r</a>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
- Set refresh measurement mode</font><br>
- </span></font><font size="-1"><span style="font-family:
+
+
+
+ Set refresh measurement mode</font><br>
+ </span></font><font size="-1"><span style="font-family:
monospace;">&nbsp;<a href="#W">-W n|h|x</a>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
Override
- serial port flow control: n = none, h = HW, x = Xon/Xoff</span></font><br>
- <small><span style="font-family: monospace;">&nbsp;</span><a
- style="font-family: monospace;" href="#D">-D [level]</a><span
- style="font-family: monospace;">
- &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
- Print debug diagnostics to stderr</span></small><br>
- &nbsp; <font size="-1"><span style="font-family: monospace;"><a
+
+
+
+ serial port flow control: n = none, h = HW, x = Xon/Xoff</span></font><br>
+ <small><span style="font-family: monospace;">&nbsp;</span><a
+ style="font-family: monospace;" href="#T">-T</a><span
+ style="font-family: monospace;">
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
+
+
+ Test mode - restore &amp; save measurements to<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
+
+ *_i.sp, *_r.sp, *_p.sp, *_mpir.sp, *_cpir.sp files<br>
+ </span></small> <small><span style="font-family: monospace;">&nbsp;</span><a
+ style="font-family: monospace;" href="#D">-D [level]</a><span
+ style="font-family: monospace;">
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
+ Print debug diagnostics to stderr</span></small><br>
+ &nbsp; <font size="-1"><span style="font-family: monospace;"><a
href="#file"><span style="font-style: italic;">illuminant.sp</span></a>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
File
- to save measurement to<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>illumread</b> uses a suitable instrument to read an illuminant
- spectrum, and uses an indirect method to estimate the Ultra Violet
- content of the illuminant, so as to provide better accuracy with <a
- href="FWA.html">FWA compensation</a>. An instrument or combination
- of instruments capable of spectral measurement of both emissive
- measurement and reflective measurement without a U.V. filter is
- required for this.<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 plotting of the
- spectral reflectance/transmittance values. You must select the plot
- window and strike a key in it to continue with another measurement.<br>
- <br>
- <a name="c"></a> The instrument is assumed to communicate through a
- USB or serial communication port, and the initial 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;">illumread</span> so as to display the
- usage information (i.e. "illumread -?" or "illumread --"), 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="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="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="Yr"></a> The -<span style="font-weight: bold;">Y r</span>
- option turns on refresh mode measurement, if the instrument supports
- it. This may improve the repeatability of measurements of
- illuminants that have a repetitive flicker.<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="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="file"></a>The <span style="font-weight: bold; font-style:
- italic;">illuminant.sp</span> is the name of the file to save the
- resulting illuminant spectrum to. The format used is <a
- href="File_Formats.html#.sp">.sp</a>.<br>
- <br>
- <hr style="width: 100%; height: 2px;"><br>
- Unlike the other measurement utilities, <span style="font-weight:
- bold;">illumread</span> doesn't connect to the instrument until it
- is about to make a measurement. This allows for the possibility of
- using a different instrument for each measurement.<br>
- <br>
- It will display a menu:<br>
- <br>
- Press 1 .. 6<br>
- 1) Measure direct illuminant<br>
- 2) Measure illuminant reflected from paper<br>
- 3) Measure paper<br>
- 4) Select another instrument, Currently 1 'usb:/bus4/dev2/
- (GretagMacbeth i1 Pro)'<br>
- 5) Compute illuminant spectrum, average result with 0 previous
- readings &amp; save it<br>
- 6) Compute illuminant spectrum from this reading &amp; save result<br>
- 7) Exit<br>
- <br>
- There are three measurements to be made, after which the illuminant
- can be computed and saved. Before each measurement, the instrument
- may need calibrating.<br>
- <br>
- The first measurement needs a spectral instrument capable of reading
- in an ambient or emissive mode. For instance, a Spectrolino, Eye-One
- Pro or ColorMunki would be suitable instruments.<br>
- <br>
- The second measurement needs a spectral instrument capable of
- reading in an projector or emissive mode. For instance, a
- Spectrolino, Eye-One Pro or ColorMunki would be suitable
- instruments.<br>
- <br>
- The third measurement needs a spectral instrument capable of reading
- in reflective mode with UV included. For instance, a Spectrolino,
- Eye-One Pro, DTP20, DTP22 or&nbsp; DTP41 would be suitable
- instruments, as long as they are not fitted with UV filters.<br>
- <br>
- To be able to estimate the level of Ultra Violet (UV) light in the
- illuminant, a reasonable sized piece of white paper needs to be
- used. The paper should have some noticeable level of FWA
- (Fluorescent Whitener Additive, or Optical Brightening Agents) in
- it, so that it responds to UV light. A piece of cheap copier paper
- is ideal, since cheap paper is typically whitened with large amounts
- of FWA. If the paper is thin (less than 160 gsm) then two or three
- sheets should be used to prevent any background showing through. [If
- the intention is to use the illuminant spectrum for proofing to a
- particular paper, then an alternative might be to use a piece of the
- intended paper for this purpose. It's unclear which may give a
- better result.]<br>
- <br>
- The first measurement <span style="font-weight: bold;">1)</span>,
- is to use either the ambient or emissive measurement mode to measure
- the illumination directly.<br>
- <br>
- <div style="margin-left: 40px;">If the instrument supports an
- ambient measurement capability, then it will be used. If the
- insrument does not have an ambient mode, then an emissive
- measurement mode can be used, although typically many illuminants
- are too bright to directly point the instrument at. A work-around
- is to reflect the illuminant from a spectrally flat white surface.
- A good candidate for this is a piece of white, fine textured
- polystyrene foam. [The suitability of a reflector can be checked
- using <span style="font-weight: bold;">spotread -S</span> to
- check that the reflection characteristic is close to flat.]<br>
- <br>
- <img style="width: 228px; height: 300px;" alt="Measuring Ambient"
- src="illumread_1.jpg"><img style="width: 141px; height: 282px;"
- alt="Measuring Ambient" src="illumread_2.jpg">&nbsp; <img
- style="width: 226px; height: 282px;" alt="Measuring Ambient"
- src="illumread_3.jpg"><br>
- </div>
- <br>
- The second measurement <span style="font-weight: bold;">2)</span>,
- is to measure the illuminant after it has reflected from the paper.<br>
- <br>
- <div style="margin-left: 40px;">This is done by placing the paper
- such that it is uniformly illuminated with reasonable brightness,
- and then placing the instrument so that it receives the reflected
- light from the paper. This is typically achieved by placing the
- instrument close to the paper at about 45&ordm;, so that it's
- aperture has a clear view of the illuminated paper, but avoiding
- shadowing the region that is in view. <br>
- <br>
- <img style="width: 219px; height: 261px;" alt="Measuring via
- Paper" src="illumread_5.jpg"><img style="width: 252px; height:
- 259px;" alt="Measuring via Paper" src="illumread_4.jpg"><br>
- </div>
- <br>
- The third measurement <span style="font-weight: bold;">3)</span>,
- is to measure the paper directly using the instrument reflective
- mode measurement.<br>
- <div style="margin-left: 40px;"><img style="width: 186px; height:
- 162px;" alt="Measuring Paper" src="illumread_6.jpg"><br>
- </div>
- If a different instrument is needed, use <span style="font-weight:
- bold;">4)</span> to select from the available instruments attached
- to your computer.<br>
- <br>
- Once these three measurements have been made, then the illuminant
- readings spectrum can be computed and save using <span
- style="font-weight: bold;">6)</span>, or a series of readings can
- be made with each reading being averages with the previous readings
- before saving it by using <span style="font-weight: bold;">5)</span>.
- Note that the averaged readings will be weighted by their absolute
- intensities, and that while the direct and indirect illumination
- needs measuring for each reading, the same paper measurement can be
- used each time.<br>
- <br>
- If plotting is enabled, a plot of the measured (black) and with
- estimated UV (red) is plotted. This is followed by a plot showing
- measured paper reflectance (black) and the FWA calculated paper
- reflectance (red).<br>
- <br>
- <br>
- Illumread can then be terminated using <span style="font-weight:
- bold;">7)</span>.<br>
- <br>
- <br>
- <br>
- <br>
- <br>
- <br>
- <br>
- <br>
- <br>
- <br>
- <br>
- </body>
-</html>
+
+
+
+ to save measurement to<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>illumread</b> uses a suitable instrument to read an illuminant
+ spectrum, and uses an indirect method to estimate the Ultra Violet
+ content of the illuminant, so as to provide better accuracy with <a
+ href="FWA.html">FWA compensation</a>. An instrument or combination
+ of instruments capable of spectral measurement of both emissive
+ measurement and reflective measurement without a U.V. filter is
+ required for this.<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 plotting of the
+ spectral reflectance/transmittance values. You must select the plot
+ window and strike a key in it to continue with another measurement.<br>
+ <br>
+ <a name="c"></a> The instrument is assumed to communicate through a
+ USB or serial communication port, and the initial 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;">illumread</span> so as to display the
+ usage information (i.e. "illumread -?" or "illumread --"), 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="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="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="Yr"></a> The -<span style="font-weight: bold;">Y r</span>
+ option turns on refresh mode measurement, if the instrument supports
+ it. This may improve the repeatability of measurements of
+ illuminants that have a repetitive flicker.<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="T"></a>The <b>-T</b> flag invokes the test mode. In test
+ mode the three measurements are saved to files <i>illuminant</i><i>_i.sp</i>
+ (Illuminant spectrum), <i>illuminant</i><i>_r.sp</i> (Illuminant
+ off paper spectrum), and <i>illuminant_p.sp (</i>Instrument
+ measured paper reflectance spectrum), and these will be loaded if
+ discovered, allowing a replay of the calculation without requiring
+ any measurement. In addition, two diagnostic files <i>illuminant</i><i>_mpir.sp</i>
+ (Measured paper under illuminant spectrum) and <i>illuminant</i><i>_cpir.sp
+
+ (</i>Computed paper under illuminant spectrum) will be saved.<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="file"></a>The <span style="font-weight: bold; font-style:
+ italic;">illuminant.sp</span> is the name of the file to save the
+ resulting illuminant spectrum to. The format used is <a
+ href="File_Formats.html#.sp">.sp</a>.<br>
+ <br>
+ <hr style="width: 100%; height: 2px;"><br>
+ Unlike the other measurement utilities, <span style="font-weight:
+ bold;">illumread</span> doesn't connect to the instrument until it
+ is about to make a measurement. This allows for the possibility of
+ using a different instrument for each measurement.<br>
+ <br>
+ It will display a menu:<br>
+ <br>
+ Press 1 .. 6<br>
+ 1) Measure direct illuminant<br>
+ 2) Measure illuminant reflected from paper<br>
+ 3) Measure paper<br>
+ 4) Select another instrument, Currently 1 'usb:/bus4/dev2/
+ (GretagMacbeth i1 Pro)'<br>
+ 5) Compute illuminant spectrum, average result with 0 previous
+ readings &amp; save it<br>
+ 6) Compute illuminant spectrum from this reading &amp; save result<br>
+ 7) Exit<br>
+ <br>
+ There are three measurements to be made, after which the illuminant
+ can be computed and saved. Before each measurement, the instrument
+ may need calibrating.<br>
+ <br>
+ The first measurement needs a spectral instrument capable of reading
+ in an ambient or emissive mode. For instance, a Spectrolino, Eye-One
+ Pro or ColorMunki would be suitable instruments.<br>
+ <br>
+ The second measurement needs a spectral instrument capable of
+ reading in an projector or emissive mode. For instance, a
+ Spectrolino, Eye-One Pro or ColorMunki would be suitable
+ instruments.<br>
+ <br>
+ The third measurement needs a spectral instrument capable of reading
+ in reflective mode with UV included. For instance, a Spectrolino,
+ Eye-One Pro, DTP20, DTP22 or&nbsp; DTP41 would be suitable
+ instruments, as long as they are not fitted with UV filters.<br>
+ <br>
+ To be able to estimate the level of Ultra Violet (UV) light in the
+ illuminant, a reasonable sized piece of white paper needs to be
+ used. The paper should have some noticeable level of FWA
+ (Fluorescent Whitener Additive, or Optical Brightening Agents) in
+ it, so that it responds to UV light. A piece of cheap copier paper
+ is ideal, since cheap paper is typically whitened with large amounts
+ of FWA. If the paper is thin (less than 160 gsm) then two or three
+ sheets should be used to prevent any background showing through. If
+ the intention is to use the illuminant spectrum for proofing to a
+ particular paper, then it's best to use the intended paper for this
+ purpose.<br>
+ <br>
+ The first measurement <span style="font-weight: bold;">1)</span>,
+ is to use either the ambient or emissive measurement mode to measure
+ the illumination directly.<br>
+ <br>
+ <div style="margin-left: 40px;">If the instrument supports an
+ ambient measurement capability, then it will be used. If the
+ insrument does not have an ambient mode, then an emissive
+ measurement mode can be used, although typically many illuminants
+ are too bright to directly point the instrument at. A work-around
+ is to reflect the illuminant from a spectrally flat white surface.
+ A good candidate for this is a piece of white, fine textured
+ polystyrene foam. [The suitability of a reflector can be checked
+ using <span style="font-weight: bold;">spotread -S</span> to
+ check that the reflection characteristic is close to flat.]<br>
+ <br>
+ <img style="width: 228px; height: 300px;" alt="Measuring Ambient"
+ src="illumread_1.jpg"><img style="width: 141px; height: 282px;"
+ alt="Measuring Ambient" src="illumread_2.jpg">&nbsp; <img
+ style="width: 226px; height: 282px;" alt="Measuring Ambient"
+ src="illumread_3.jpg"><br>
+ </div>
+ <br>
+ The second measurement <span style="font-weight: bold;">2)</span>,
+ is to measure the illuminant after it has reflected from the paper.<br>
+ <br>
+ <div style="margin-left: 40px;">This is done by placing the paper
+ such that it is uniformly illuminated with reasonable brightness,
+ and then placing the instrument so that it receives the reflected
+ light from the paper. This is typically achieved by placing the
+ instrument close to the paper at about 45º, so that it's aperture
+ has a clear view of the illuminated paper, but avoiding shadowing
+ the region that is in view. <br>
+ <br>
+ <img style="width: 219px; height: 261px;" alt="Measuring via
+ Paper" src="illumread_5.jpg"><img style="width: 252px; height:
+ 259px;" alt="Measuring via Paper" src="illumread_4.jpg"><br>
+ </div>
+ <br>
+ The third measurement <span style="font-weight: bold;">3)</span>,
+ is to measure the paper directly using the instrument reflective
+ mode measurement.<br>
+ <div style="margin-left: 40px;"><img style="width: 186px; height:
+ 162px;" alt="Measuring Paper" src="illumread_6.jpg"><br>
+ </div>
+ If a different instrument is needed, use <span style="font-weight:
+ bold;">4)</span> to select from the available instruments attached
+ to your computer.<br>
+ <br>
+ Once these three measurements have been made, then the illuminant
+ readings spectrum can be computed and save using <span
+ style="font-weight: bold;">6)</span>, or a series of readings can
+ be made with each reading being averages with the previous readings
+ before saving it by using <span style="font-weight: bold;">5)</span>.
+ Note that the averaged readings will be weighted by their absolute
+ intensities, and that while the direct and indirect illumination
+ needs measuring for each reading, the same paper measurement can be
+ used each time.<br>
+ <br>
+ If plotting is enabled, a plot of the measured (black) and with
+ estimated UV (red) is plotted. This is followed by a plot showing
+ measured paper reflectance (black) and the FWA calculated paper
+ reflectance (red).<br>
+ <br>
+ <br>
+ Illumread can then be terminated using <span style="font-weight:
+ bold;">7)</span>.<br>
+ <br>
+ <br>
+ <br>
+ <br>
+ <br>
+ <br>
+ <br>
+ <br>
+ <br>
+ <br>
+ <br>
+ </body>
+</html>