<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>printcal</title> <meta http-equiv="content-type" content="text/html; charset=ISO-8859-1"> <meta name="author" content="Graeme W. Gill"> </head> <body> <h2> profile/printcal</h2> <h3>Summary</h3> Create a printer linearization calibration file from <a href="File_Formats.html#.ti3">.ti3</a> test chart patch values.<br> <h3>Usage Summary</h3> <span style="font-family: monospace;">printcal</span><small style="font-family: monospace;"> [-<i>options</i>] [prevcal] inoutfile<br> <a href="#v">-v verbosity</a> Set verbosity level<br> </small><small style="font-family: monospace;"> <a href="#p">-p</a> Plot graphs.<br> <a href="#i">-i</a> Initial calibration, set targets, create .cal<br> </small><small style="font-family: monospace;"> <a href="#r">-r</a> Re-calibrate against previous .cal and create new .cal</small><br style="font-family: monospace;"> <span style="font-family: monospace;"></span><small style="font-family: monospace;"> <a href="#e">-e</a> Verify against previous .cal<br> </small><small style="font-family: monospace;"> <a href="#I">-I</a> Create imitation target from .ti3 and null calibration</small><br> <small style="font-family: monospace;"> <a href="#d">-d</a> Go through the motions but don't write any files</small><br style="font-family: monospace;"> <small><span style="font-family: monospace;"> </span><a style="font-family: monospace;" href="#A">-A "manufacturer"</a><span style="font-family: monospace;"> Set the manufacturer description string</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> </span><a style="font-family: monospace;" href="#M">-M "model"</a><span style="font-family: monospace;"> Set the model description string</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> </span><a style="font-family: monospace;" href="#D">-D "description"</a><span style="font-family: monospace;"> Set the profile Description string </span><br style="font-family: monospace;"> <span style="font-family: monospace;"> </span><a style="font-family: monospace;" href="#C">-C "copyright"</a><span style="font-family: monospace;"><span style="font-family: monospace;"> Set the copyright string</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> </span><a style="font-family: monospace;" href="#x">-x# percent</a><span style="font-family: monospace;"> Set maximum device percentage target</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> </span><a style="font-family: monospace;" href="#n">-n# deltaE</a><span style="font-family: monospace;"> Set white minimum deltaE target</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> </span><a style="font-family: monospace;" href="#t">-t# percent</a><span style="font-family: monospace;"> Set 50% transfer curve percentage target</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> # = c, r, 0 First channel</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> m, g, 1 Second channel</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> y, b, 2 Third channel</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> k, 3 Fourth channel, etc.<br> <a href="#a">-a</a> Create an Adobe Photoshop .AMP file as well as a .cal<br style="font-family: monospace;"> </span><span style="font-family: monospace;"> </span><a style="font-family: monospace;" href="#p1">prevcal</a><span style="font-family: monospace;"> Base name of previous .cal file for recal or verify.</span><br style="font-family: monospace;"> <span style="font-family: monospace;"> </span><a style="font-family: monospace;" href="#p2">inoutname</a><span style="font-family: monospace;"> Base name of input .ti3 file, output .cal file</span><br> </span><span style="font-family: monospace;"></span></small><small><span style="font-family: monospace;"></span><span style="font-family: monospace;"></span><span style="font-family: monospace;"></span></small><br> <h3>Options<br> </h3> <b><a name="v"></a>-v</b> Turn on verbose mode. Gives progress information as the calibration is created. An argument greater than 1 increases the verbosity. Will also report the ideal power value to apply to the test chart in targen.<br> <br> <a name="p"></a><span style="font-weight: bold;">-p</span> Turns on plot mode. This causes various graphs to be plotted as the calibration is created. The channels will be plotted in the graph colors: Blue, Red, Yellow, Black, Green, Purple, Brown, Orange, Grey, White.<br> <br> <a name="i"></a><span style="font-weight: bold;">-i</span> Select initial calibration mode. Initial calibration mode allows setting the targets for the calibration, such as maximum device percentage, minimum white level, and the transfer curve shape. The second last parameter <span style="font-weight: bold;"><span style="font-weight: bold;"></span>prevcal</span> is not used in this mode.<br> <br> <a name="r"></a><span style="font-weight: bold;">-r</span> Turns on re-calibration mode. This is used for calibrations after the initial one, where the aim is to return the devices response to the same state as it was after the initial caibration. Parameters that affect the calibration targets are ignored. The second last parameter <span style="font-weight: bold;"><span style="font-weight: bold;"></span>prevcal</span> is used to establish what the targets for the calibration are.<br> <br> <a name="e"></a><span style="font-weight: bold;">-e</span> Turns on verify mode. In this mode the test chart input is verified agains the expected response in the <span style="font-weight: bold;"><span style="font-weight: bold;"></span>prevcal</span> file.<br> <br> <a name="I"></a><span style="font-weight: bold;">-I</span> Similar to <span style="font-weight: bold;">-i</span>, except that rather than creating a linear target curve and corresponding calibration, it takes the given behaviour as an absolute target and create a corresponding null set of calibration curves. This .cal can then be used to recalibrate a similar device (or the same device at some other time) to imitate the behaviour of the initial device. The second last parameter <span style="font-weight: bold;"><span style="font-weight: bold;"></span>prevcal</span> is not used in this mode. Parameters that affect the calibration targets are ignored.<br> <br> <a name="d"></a><span style="font-weight: bold;">-d</span> Disables the writing of any files, causing printcal to go through the motions without changing anything.<br> <br> <a name="A"></a>The <b>-A</b> parameter allows setting of the device manufacturer description string in the calibration file. The parameter should be a string that identifies the manufacturer of the device being profiled. With most command line shells, it will be necessary to enclose the parameter with double quotes, so that spaces and other special characters are included in the parameter, and not mistaken for the start of another flag or as a final command line parameters. By default no device manufacturer description string will be put in the calibration file.<br> <br> <a name="M"></a>The <b>-M</b> parameter allows setting of the device mode description string in the calibration file. The parameter should be a string that identifies the particular model of device being profiled. With most command line shells, it will be necessary to enclose the parameter with double quotes, so that spaces and other special characters are included in the parameter, and not mistaken for the start of another flag or as a final command line parameters. By default no model description string will be put in the calibration file.<br> <br> <a name="D"></a>The <b>-D</b> parameter allows setting of the profile description string in the calibration file. The parameter should be a string that describes the device and profile. On many systems, it will be this string that will be used to identify the profile from a list of possible profiles. With most command line shells, it will be necessary to enclose the parameter with double quotes, so that spaces and other special characters are included in the parameter, and not mistaken for the start of another flag or as a final command line parameter. By default no profile description string will be put in the calibration file.<br> <br> <a name="C"></a>The <b>-C</b> parameter allows setting of the profile copyright string in the calibration file. The parameter should be a string that describes the copyright (if any) claimed on the profile being generated. With most command line shells, it will be necessary to enclose the parameter with double quotes, so that spaces and other special characters are included in the parameter, and not mistaken for the start of another flag or as a final command line parameters. By default no copyright string will be put in the calibration file.<br> <br> <a name="x"></a> The <b>-x</b> parameter allows overriding the default maximum device value computed from the raw device response. The default uses a heuristic to decide when the response of the device to each channels colorant value reaches the point of diminishing returns, while the <span style="font-weight: bold;">-x</span> parameter allows this default to be overridden. The <span style="font-weight: bold;">-x</span> paramater can be used multiple times, once for each channel that is being set. The <span style="font-weight: bold;">-x</span> should be followed by the channel number between 0 and 15, or the aliases <span style="font-weight: bold;">r</span>, <span style="font-weight: bold;">g</span> or <span style="font-weight: bold;">g</span>, or <span style="font-weight: bold;">c</span>, <span style="font-weight: bold;">m</span>, <span style="font-weight: bold;">y</span> or <span style="font-weight: bold;">k,</span> and the channel number should then be followed by the device value as a percentage. <span style="font-weight: bold;">NOTE</span> that you will probably get sub-optimal results if you force a device maximum that is beyond the point of maximum response of a device channel, since this will have the effect of <span style="text-decoration: underline;">reducing</span> the device response.<br> <br> <a name="n"></a> The <b>-n</b> parameter allows overriding the default minimum deltaE of a colorant to white of 0. This can be used to set a minimum colorant level in order to emulate media darker or of a different tint. The <span style="font-weight: bold;">-n</span> paramater can be used multiple times, once for each channel that is being set. The <span style="font-weight: bold;">-n</span> should be followed by the channel number between 0 and 15, or the aliases <span style="font-weight: bold;">r</span>, <span style="font-weight: bold;">g</span> or <span style="font-weight: bold;">g</span>, or <span style="font-weight: bold;">c</span>, <span style="font-weight: bold;">m</span>, <span style="font-weight: bold;">y</span> or <span style="font-weight: bold;">k,</span> and the channel number should then be followed by the deltaE value.<span style="font-family: monospace;"></span><br> <br> <a name="t"></a> The <b>-t</b> parameter allows setting a target linearization curve that is other than purely linear. The default is to create a calibration curve that results in a perfectly even change in output for each change in the calibrated device value, as measured by steps in delta E94. The <span style="font-weight: bold;">-x</span> parameter allows setting a target curve above or belowe the perfectly linear, by setting the aim value at 50% input. An aim higher than 50% will cause that channel to become more intense by the 50% mark, while a value lower than 50% will cause the channel to become less intense by the 50% mark than perfectly linear.The <span style="font-weight: bold;">-x</span> should be followed by the channel number between 0 and 15, or the aliases <span style="font-weight: bold;">r</span>, <span style="font-weight: bold;">g</span> or <span style="font-weight: bold;">g</span>, or <span style="font-weight: bold;">c</span>, <span style="font-weight: bold;">m</span>, <span style="font-weight: bold;">y</span> or <span style="font-weight: bold;">k,</span> and the channel number should then be followed by the device value as a percentage.<br> <br> <a name="a"></a><span style="font-weight: bold;">-a</span> Creates an Adobe Photoshop <span style="font-weight: bold;">.AMP</span> format curves file as well as a .cal.<br> <span style="font-weight: bold;"></span><br> <a name="p1"></a> The optional second last parameter is the file base name for a previous <a href="File_Formats.html#CAL">.cal</a> calibration file, used as the target reference for recalibrate and verify modes. <br> <br> <a name="p2"></a> The final parameter is the file base name for the <a href="File_Formats.html#.ti3">.ti3</a> input test point data, and the resulting <a href="File_Formats.html#CAL">.cal</a> calibration file output. <br> <h3><a name="DISCUSSION"></a>Discussion</h3> <span style="font-weight: bold;">Printcal</span> is a tool for creating per device channel linearization curves for printing devices.<br> <br> As input it takes a .ti3 file containing the results of printing a test chart on the <span style="text-decoration: underline;">non-color managed</span>, <span style="text-decoration: underline;">non-calibrated</span> device, and measuring it. The test chart consists of step wedges for each of the device primary colors, from the media white to full individual colorant intensity.<br> <br> For the initial calibration (<span style="font-weight: bold;">-i</span>), the range of device values to be used and the shape of the target linearization curve are established, as well as creating the first set of calibration curves. For subsequent re-calibrations (<span style="font-weight: bold;">-r</span>), the calibration curves aim to reproduce the same response as the original calibration. If a test chart is printed with calibration enabled and then is mesured, it can be used to verify the calibration against the expected response (<span style="font-weight: bold;">-e</span>).<br> <br> As each colorant steps through the test wedge patches from media white, they trace out a measured locus in CIE L*a*b* colorspace. Each channel response is evaluated by computing the CIE DeltaE to media white of the response to a change in each individual channel of each locus. This measure is used to determine when the devices response to a colorant level is reaching diminishing returns, setting a maximum colorant value. This measure can also be used to set a minimum colorant value for the purposes of emulating a different media color. The default maximum and minum values for each colorant can be overriden using the <span style="font-weight: bold;">-x</span> and <span style="font-weight: bold;">-n</span> parameters.<br> <br> The actual linearization uses a subtly different measure, which is the CIE DelataE 94 along each colorant response locus, ensuring that after linearization each step in colorant value is subjectively even. The linearization aim can be altered from a purely linear curve by using the <span style="font-weight: bold;"><span style="font-weight: bold;">-t</span></span> parameters.<br> <br> After the initial calibration, the device can be re-calibrated (<span style="font-weight: bold;">-r</span>) by printing a calibration test chart under the same conditions as the initial one, but with the calibration aimed at reproducing the same response as the initial calibration, rather that setting new targets.<br> <br> The calibration can be verified (<span style="font-weight: bold;">-e</span>) by printing a calibration test chart on <span style="text-decoration: underline;">non-color managed</span>, <span style="text-decoration: underline;"></span>but calibrated device, the verification evaluating any discrepancy between the device response acheived, and the device response expected. For a numerical evaluation the verbose flag (<span style="font-weight: bold;">-v</span>) should be used, and for a visual evaluation the plot flag (<span style="font-weight: bold;">-p</span>) should be used.<br> <br> If there are several devices of the same or similar model, then one device can be used to set the initial calibration target, and then the other devices can be re-calibrated against the same .cal file, to create matching responses. An alternative to creating an initial linear target for calibration, is to use the <span style="font-weight: bold;">-I</span> option with an initial device, which sets the initial target to be that devices absolute response. Naturally the corresponding calibration will be linear (null). The calibration target can then be used to later return that device to its initial response, or to make another similar device have the same response. Note though, that bad things will happen if the imitated devices response is non-monotonic, or if on re-calibration the device is unable to reach the same density levels.<br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> </body> </html>
