<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>refine</title> <meta http-equiv="content-type" content="text/html; charset=ISO-8859-1"> <meta name="author" content="Graeme Gill"> </head> <body> <h2><b>tweak/refine</b></h2> <h3>Summary</h3> <span style="font-weight: bold;">Refine</span> creates an abstract profile, by comparing CIE measurement values from two test charts. The charts will usually be in <a href="File_Formats.html#.ti3">.ti3</a> format, but only XYZ, Lab or spectral values will be used. Typically the charts would be printed on a target system (the one being emulated, say a printing press), and the proofing system (the one that is being profiled). The abstract profile that <span style="font-weight: bold;">refine</span> produces will be a correction that makes the proofing system behave more like the target. This can then be used to recreate the proofing systems ICC profile, or device link. By feeding a previous abstract correction profile in as well, iterative improvement can be made to the proofing reproduction.<br> <br> <a href="verify.html">verify</a> is a useful tool to use on the two test charts, to check how well the refinement is proceeding. If a white point relative match is being created (refine -R), then use veryify -N.<br> <h3>Usage Summary</h3> <small><span style="font-family: monospace;">usage: refine [-options] cietarget ciecurrent [outdevicc] [inabs] outabs</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> -v Verbose</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> -c Create initial abstract correction profile</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> -g Don't impose output device gamut limit</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> -r res Set abstract profile clut resolution (default 33)</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> -d factor Override default damping factor (default 0.950000)<br> -R Aim for white point relative match rather than absolute<br style="font-family: monospace;"> </span><span style="font-family: monospace;"> -i illum Choose illuminant for spectral data:</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> A, C, D50 (def.), D65, F5, F8, F10 or file.sp</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> -o observ Choose CIE Observer for spectral data:</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> 1931_2, 1964_10, S&B 1955_2, J&V 1978_2 (def.)</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> -f Use Fluorescent Whitening Agent compensation on spectral data</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> </span><span style="font-style: italic; font-family: monospace;">cietarget </span><span style="font-family: monospace;"> Target CIE or spectral values, CGATS file (e.g. .ti3)</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> </span><span style="font-style: italic; font-family: monospace;">ciecurrent</span><span style="font-family: monospace;"> Actual CIE or spectral values, CGATS file (e.g. .ti3)</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> [</span><span style="font-style: italic; font-family: monospace;">outdevicc</span><span style="font-family: monospace;">] Output device ICC profile to set gamut limit (not used if -g)</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> [</span><span style="font-style: italic; font-family: monospace;">inabs</span><span style="font-family: monospace;">] Previous abstract correction ICC profile (not used if -c)</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> </span><span style="font-style: italic; font-family: monospace;">outabs</span><span style="font-family: monospace;"> Created/refined abstract correction ICC profile</span></small><br> <h3>Usage Details</h3> <b>refine</b> provides a way of improving the profile accuracy of a proofing system.<br> <br> The <b>-v</b> flag prints out extra information during the checking, and prints each patch value, rather than just a summary.<br> <br> The <b>-c</b> option is used when refine is being used for the first time, and there is no previous abstract profile to continue refining. If <span style="font-weight: bold;">-c</span> is used, then the name of the previous abstract correction profile should not be supplied.<br> <br> If the <b>-g </b>flag indicates that an output device profile is not being supplied, and that corrections should be attempted, even if the colors are outside the devices gamut. Normally an output device profile is supplied, and corrections aren't applied to colors outside the devices gamut, since this will not achieve anything useful, and can distort the results.<br> <br> If the <b>-r </b>parameter overrides the resolution of the CLUT grid used in the abstract profile. By default the value is 33, but other<br> values can be chosen. An odd number is recommended. <br> <br> If the <b>-d </b>parameter sets how aggressively refine should try and correct errors. Normally it will try and exactly compensate for the color errors revealed in comparing the two measurement files, but if the device behaviour is unusual, or not very repeatable, this may result in successive applications of refine making things worse, rather than better. If this is the case, try using a smaller number, such as 0.8, or 0.5.<br> <br> If the <span style="font-weight: bold;">-R</span> flag is used, then refine creates an abstract profile for improving the match of the patch values when interpreted in a white point relative (ie. Relative Colorimetric) intent. If used to create a corrected device link profile using <a href="collink.html">collink</a>, remember to create a Relative colorimetric intent device link profile.<br> <br> The <b>-i</b> flag allows specifying a standard or custom illumination spectrum, applied to the spectral test point values, to compute CIE 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> spectrum file.<br> <br> The <b>-o</b> flag allows specifying a tristimulus observer, and is used to compute CIE tristimulus values. The following choices are available:<br> <b> 1931_2</b> selects the standard CIE 1931 2 degree observer.<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> The <b>-f</b> flag enables Fluorescent Whitening Agent compensation, which compensates for the effect a different illuminant will have, on any Fluorescent Whitening Agent present in the reflective media. Spectral patch information is needed for this to function.<br> <br> If both CIE and spectral values are present in the input files, the CIE values will be used by default. Using the <span style="font-weight: bold;">-i</span>, <span style="font-weight: bold;">-o</span> or <span style="font-weight: bold;">-f</span> flag will force spectral values to be used. The the <span style="font-weight: bold;">-i</span>, <span style="font-weight: bold;">-o</span> or <span style="font-weight: bold;">-f</span> flags will apply to both the target and measured input files.<br> <br> <span style="font-style: italic; font-weight: bold;">cietarget</span> Is the filename of the target CIE or spectral values. This is a <a href="File_Formats.html#CGATS">CGATS</a> file (e.g. a <a href="File_Formats.html#.ti3">.ti3</a> made using <a href="chartread.html">chartread</a>). These are the color values wanted for each patch in the test chart, typically the product of the target print system.<br> <br> <span style="font-style: italic; font-weight: bold;">ciecurrent</span> Is the filename of the actual, current measured CIE or spectral values. This is a <a href="File_Formats.html#CGATS">CGATS</a> file (e.g. a <a href="File_Formats.html#.ti3">.ti3</a> made using <a href="chartread.html">chartread</a>). The errors between these patches and the patches in the <span style="font-style: italic; font-weight: bold;">cietarget</span> file will be used to create a correction profile.<br> <br> [<span style="font-style: italic; font-weight: bold;">outdevicc</span>] If the <span style="font-weight: bold;">-g</span> flag is not used, then the output device ICC profile should be supplied here, to allow <span style="font-weight: bold;">refine</span> to limit its corrections to colors that are within the gamut of the device.<br> <br> [<span style="font-weight: bold; font-style: italic;">inabs</span>] After the first correction has been created, subsequent corrections need to improve upon previous ones, so the previous correction profile should be provided here. For the first correction, the <span style="font-weight: bold;">-c</span> flag should be used, and this argument is omitted.<br> <br> <span style="font-weight: bold; font-style: italic;">outabs</span> The name of the created or refined abstract correction ICC profile<br> <br> <h3> Discussion</h3> <span style="font-weight: bold;">Refine</span> is typically used in a proofing situation, in which a verification chart is being used to check the accuracy of a proofing system. (It might also be used for more arbitrary color alterations by created two test chart files by hand.) By using the errors between the target chart and the measured values, refine attempts to improve the match between the proofing system and its target.<br> <br> There is facility in <a href="collink.html">collink</a>, <a href="colprof.html">colprof</a> and <a href="revfix.html">revfix</a> to incorporate an abstract profile. <br> <br> For systems using two device profiles or a device link to convert between the target space printing files and the proofing device space, the following would be a typical scenario:<br> <br> <div style="margin-left: 40px;">We have a reference set of test chart values, read from the target system <span style="font-weight: bold;">reference.ti3</span>. The ICC profile for the target system is <span style="font-weight: bold;">target.icm</span>. The ICC profile for the proofing system is <span style="font-weight: bold;">proofer.icm</span>. If using a device link, the device link used to print proofer test charts is currently <span style="font-weight: bold;">target_proofer.icm</span>:<br> <br> <br> First we print the test chart out on the proofing system and read it in, resulting in a <span style="font-weight: bold;">chart1.ti3</span> file.<br> <br> Lets check how well the proofing system current matches using verify:<br> <br> verify reference.ti3 chart1.ti3<br> <br> We then create our initial abstract correction fix profile <span style="font-weight: bold;">fix1.icm</span> using refine:<br> <br> refine -v -c reference.ti3 chart1.ti3 proofer.icm fix1.icm<br> <br> Applying this to your process for creating the proofer device profile or target to proofing device link (choose one of the three options below, depending whether you are using the proofer profile and just want to alter its colorimetric B2A table using <span style="font-weight: bold;">revfix</span>, whether you are going to recreate the proofer file from the original measurement data using <span style="font-weight: bold;">colprof</span>, or whether you are using a device link profile created using <span style="font-weight: bold;">collink</span>):<br> <br> revfix -v -1 -ke -p fix1.icm proofer.icm proofer_fix1.icm<br> or<br> copy proofer.ti3 proofer_fix1.ti3<br> colprof -v -p fix1.icm proofer_fix1<br> or<br> collink -v -s -ia -oa -p fix1.icm target.icm proofer.icm target_proofer_fix1.icm<br> <br> Note that the above example is a simple one - you should use all the same options as you used to create your initial <span style="font-weight: bold;"><span style="font-weight: bold;"></span>proofer.icm </span>or <span style="font-weight: bold;">target_proofer.icm</span>, with the addition of the "-p fix1.icm" option to specify the abstract correction profile be applied.<br> <br> Use the <span style="font-weight: bold;">proofer_fix1.icm</span> or <span style="font-weight: bold;">target_proofer_fix1.icm</span> to print out the test chart again, and read it in, resulting in <span style="font-weight: bold;">chart2.ti3</span> file.<br> <br> Lets check how well the proofing system matches after this first round of refinement using verify:<br> <br> verify reference.ti3 chart2.ti3<br> <br> <br> <span style="font-weight: bold;"><span style="font-weight: bold;">>>></span></span><br> <span style="font-weight: bold;"><span style="font-weight: bold;"></span></span><br> <span style="font-weight: bold;"><span style="font-weight: bold;"> </span></span>We can then start another round of improvement:<br> <br> We refine our previous abstract correction fix profile using refine:<br> <br> refine -v reference.ti3 chart2.ti3 proofer.icm fix1.icm fix2.icm<br> <br> Applying this new abstract profile to our process for creating the proofing device profile or link again:<br> <br> revfix -v -1 -ke -p fix2.icm proofer.icm proofer_fix2.icm<br> or<br> copy proofer.ti3 proofer_fix2.ti3<br> colprof -v -p fix2.icm proofer_fix2<br> or<br> collink -v -s -ia -oa -p fix2.icm target.icm proofer.icm target_proofer_fix2.icm<br> <br> Use the <span style="font-weight: bold;">proofer_fix2.icm</span> or <span style="font-weight: bold;">target_proofer_fix2.icm</span> to print out the test chart again, and read it in, resulting in <span style="font-weight: bold;">chart3.ti3</span> file.<br> <br> Check again how well the proofing system matches after this first round of refinement using verify:<br> <br> verify reference.ti3 chart3.ti3<br> <br> Rounds of improvements can be continues by looping back to <span style="font-weight: bold;">>>></span>, being careful to increment the names of the <span style="font-weight: bold;">fixN.icm</span>, <span style="font-weight: bold;">proofer_fixN.icm</span> or <span style="font-weight: bold;">target_proofer_fixN.icm</span> and <span style="font-weight: bold;">chartN.ti3</span>files. Stop when exhausted, or if it looks like things are getting worse, rather than better. If the latter happens, it might be good to revert to the results from a previous round.<br> </div> <br> <br> <br> <br> <br> <br> <br> </body> </html>