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| author | Jörg Frings-Fürst <debian@jff-webhosting.net> | 2014-09-01 13:56:46 +0200 |
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| committer | Jörg Frings-Fürst <debian@jff-webhosting.net> | 2014-09-01 13:56:46 +0200 |
| commit | 22f703cab05b7cd368f4de9e03991b7664dc5022 (patch) | |
| tree | 6f4d50beaa42328e24b1c6b56b6ec059e4ef21a5 /doc/printcal.html | |
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diff --git a/doc/printcal.html b/doc/printcal.html new file mode 100644 index 0000000..89264c5 --- /dev/null +++ b/doc/printcal.html @@ -0,0 +1,399 @@ +<!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;"> + <tt> </tt><tt><a href="#C">-C "copyright"</a></tt><tt> + Set the copyright string</tt><tt><br> + </tt><tt> </tt><tt> </tt><tt><a href="#x">-x# percent</a></tt><tt> +Set +initial + + maximum device % target (override auto)</tt><tt><br> + </tt></small><small><span style="font-family: monospace;"><small> <a + href="#m">-m# percent</a> + + Set initial dev target to % of auto maximum<br> + </small> <a href="#n">-n# deltaE</a> + Set initial white + minimum deltaE target<br> + <a href="#t">-t# percent</a> +Set +initial + + 50% transfer curve percentage target<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 auto maximum device target value computed from the raw + device response for the initial calibration. 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. If you want to + set a conservative target to allow for recalibration later, see the + <b>-m</b> flag below.<br> + <br> + <a name="m"></a> The <b>-m</b> parameter allows modifying the + default auto maximum device target value for the initial + calibration. The auto maximum is computed as described above, and is + then scaled by the <b>-m</b> parameter value. Typically this will + be a scale down (ie. <b>90%</b>) to allow some margin to increase + the channel value if the channel density drops in a future + recalibration. Scaling the maximum down will reduce gamut, but + allows scope for stable behaviour using calibration. The <span + style="font-weight: bold;">-m</span> paramater can be used + multiple times, once for each channel that is being set. The <span + style="font-weight: bold;">-m</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="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 visual 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 below the perfectly visual 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 measured, + 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 minimum values for + each colorant can be overridden using the <span style="font-weight: + bold;">-x</span> and <span style="font-weight: bold;">-n</span> + parameters. The automatically determined maximum may be modified + (scaled) using the <b>-m</b> parameter, which can be useful in + allowing some margin for future calibrations to compensate for a + drop in density.<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 achieved, 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> |