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diff --git a/doc/revfix.html b/doc/revfix.html new file mode 100644 index 0000000..4892de2 --- /dev/null +++ b/doc/revfix.html @@ -0,0 +1,252 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> +<html> +<head> + <title>revfix</title> + <meta http-equiv="content-type" + content="text/html; charset=ISO-8859-1"> + <meta name="author" content="Graeme Gill"> +</head> +<body> +<h2><b>xicc/revfix</b></h2> +<h3>Summary</h3> +Regenerate a CLUT device profiles B2A table data by inverting the A2B +table.<br> +<h3>Usage Summary</h3> +<small><span style="font-family: monospace;">revfix [-options] iccin +iccout</span><br style="font-family: monospace;"> +<span style="font-family: monospace;"> -v + + Verbose</span><br + style="font-family: monospace;"> +<span style="font-family: monospace;"> -0 + + Process perceptual</span><br + style="font-family: monospace;"> +<span style="font-family: monospace;"> -1 + + Process absolute/relative colorimetric</span><br + style="font-family: monospace;"> +<span style="font-family: monospace;"> -2 + + Process saturation</span><br + style="font-family: monospace;"> +<span style="font-family: monospace;"> -r res + + Override BtoA1 +CLUT res.</span><br style="font-family: monospace;"> +<span style="font-family: monospace;"> </span><a + style="font-family: monospace;" href="#k">-k</a><span + style="font-family: monospace;"> [ezhxr] + e = +same K as existing BtoA table (def)</span><br + style="font-family: monospace;"> +<span style="font-family: monospace;"> + z = +zero, h = 0.5 K, x = max K, r = ramp K</span><br + style="font-family: monospace;"> +<span style="font-family: monospace;"> </span><a + style="font-family: monospace;" href="#kp">-k p stle stpo enle enpo +shape</a><br style="font-family: monospace;"> +<span style="font-family: monospace;"> + p = +curve parameters</span><br style="font-family: monospace;"> +<span style="font-family: monospace;"> + stle: K +level at White 0.0 - 1.0</span><br style="font-family: monospace;"> +<span style="font-family: monospace;"> + stpo: +start point of transition Wh 0.0 - Bk 1.0</span><br + style="font-family: monospace;"> +<span style="font-family: monospace;"> + enpo: +End point of transition Wh 0.0 - Bk 1.0</span><br + style="font-family: monospace;"> +<span style="font-family: monospace;"> + enle: K level at Black 0.0 - 1.0</span><br + style="font-family: monospace;"> +<span style="font-family: monospace;"> + shape: +1.0 = straight, 0.0-1.0 concave, 1.0-2.0 +convex</span><br style="font-family: monospace;"> +<span style="font-family: monospace;"> </span><a + style="font-family: monospace;" href="#K">-K parameters</a><span + style="font-family: monospace;"> Same as +-k, but +target is K locus rather than K value itself</span><br + style="font-family: monospace;"> +<span style="font-family: monospace;"> </span><a + style="font-family: monospace;" href="#l">-l tlimit</a><span + style="font-family: monospace;"> + set total ink limit, 0 +- 400% +(estimate by default)</span><br style="font-family: monospace;"> +<span style="font-family: monospace;"> </span><a + style="font-family: monospace;" href="#L">-L klimit</a><span + style="font-family: monospace;"> + set black ink limit, 0 +- 100% +(estimate by default)</span><br style="font-family: monospace;"> +<span style="font-family: monospace;"> </span><a + style="font-family: monospace;" href="#p">-p aprof.icm</a><span + style="font-family: monospace;"> +Include abstract +profile in output tables</span></small><br> +<h3>Usage Details and Discussion</h3> +Existing ICC profiles may not contain accurately inverted AtoB table +data in their B2A tables, and this tool provides a means of +addressing this, or regenerating the B2A information with a different +black generation and/or ink limit, or applying an abstract correction +profile to the B2A table, without completely recreating the profile.<br> +<br> +Currently <b>revfix</b> does not support creating real perceptual or +saturation B2A tables, but can only create relative colorimetric +tables. It also will not handle CLUT profile that use a matrix element +in them.<br> +<br> +<b>-v</b> Turn on verbose mode. Gives progress information as the +table is created. Since B2A tables can take a long time to generate, +this is often useful to monitor progress.<br> +<br> +The B2A table to be re-creating can be specified by using the <b>-0</b>, +<b>-1</b>, and <b>-2</b>f lags. Normally only the <b>-1</b> flag +should be specified, but the perceptual and saturation tables can be +replaces instead/as well, if their respective flags are specified.<br> +<br> +Normally the re-created B2A table will have the same CLUT resolution as +the existing table, but this can be overridden by using the <b>-r</b> +flag. +Typically a resolution of 9 might be used for a medium quality CMYK +table, +with 17 being used for a high quality CMYK table. For an RGB profile, a +resolution of 17 might be used for a medium quality table, and 33 being +used for a high quality table.<br> +<tt></tt><br> +<a name="k"></a> -<b>k</b> parameter sets the target level of black (K) +when creating a B2A CMYK output tables. This is often called a black +level, a black inking rule, black generation, or under color +removal. These set the target black level.<br> +<br> + Possible arguments to the <b>-k</b> flag are:<br> +<br> +<b> -kz</b> selects minimum black (0.0)<br> +<b> -kh</b> selects a black value of 0.5<br> +<b> -kx</b> selects the maximum possible black (1.0)<br> +<b> -kr</b> selects a linear black ramp, starting at minimum black for +highlight, and maximum black for shadow (equivalent to -kp 0 0 1 1 1). +This is the default.<br> +<br> +<b><a name="kp"></a>-k p stle stpo enpo enle shape</b> allows an +arbitrary black value ramp to be defined, consisting of a starting +value (stle) for highlights, a breakpoint L value (stpo) where it +starts to transition to the shadow level, an end breakpoint L (enpo) +where it flattens out again, and the finishing black level (enle) for +the shadows. There is also a curve parameter, that modifies the +transition from stle to enle to either be concave (ie. the +transition starts gradually and and finished more abruptly) using +values 0.0-1.0, with 0.0 being most concave, or convex (the transition +starts more abruptly but finishes gradually), using values 1.0-2.0, +with 2.0 being the most convex.<br> +<br> +Typical black value generation curve with parameters something +like: -kp 0 .1 .9 1 .5<br> +<br> +<tt> 1.0 K | + enpo<br> + +| _______ +enle<br> + +| /<br> + +| /<br> + +| /<br> + +| /<br> + stle +| ------/<br> + + +-------------------<br> + 0.0 K +0.0 stpo 1.0<br> + +White +Black<br> +</tt> +<br> +For minimum sensitivity of printed output to the lighting spectrum, it +currently seems best to use the maximum possible black, but other black +generation levels (ie. 0.3 to 0.5) may well be preferred if one wants +to +minimize the noisy appearance of black on an inkjet device, or +if the banding behaviour or other rendering flaws of the printer is to +be minimized. <br> + +<br> +The <a href="xicclu.html">xicclu</a> tool can be used to plot out +the resulting black level for a given set of parameters, by using the <a + href="xicclu.html#g">-g</a> flag of a profile already created from the +same .ti3 file.<br> +<br> +<a name="K"></a> <span style="font-weight: bold;">-K parameters.</span> +Any of the <span style="font-weight: bold;">-k</span> options above +can use the <span style="font-weight: bold;">-K</span> version, in +which rather than a black value target being defined by the inking +rule, a black <span style="text-decoration: underline;">locus</span> +target is defined. For each lookup, the minimum possible black level +and the maximum possible black level is determined, the former +corresponding to a locus target of 0, and the latter corresponding to a +locus target of 1. For instance, at +the +white point, no black will be used in the output, even if the black +locus specifies a maximum (since the maximum amount of black that +can be used to print white is actually zero). Similarly, at the black +point, black may well be used, even if the black locus specifies +zero black (since a certain amount of black is needed to achieve the +desired density of color). <br> +<tt> </tt><br> +<a name="l"></a>The <b>-l</b> <i>tlimit</i> parameter sets the ink +limit (TAC, Total +Area Coverage) for the CMYK separation, as a total percentage from 0% +to 400%. By default, this value will be estimated from the profile. The +limit value should generally be set a little below the value used in +the test chart +generation, to avoid the very edges of the gamut. If the test chart ink +limit has been chosen to be a little beyond an acceptable level, then +this +number should be the acceptable level. Although limits can be set below +200%, this will generally restrict the color gamut noticeably, as fully +saturated +secondary colors will not be reproduced. Values are between 220% and +300% +for typical printing devices. The ink limit +will be in final calibrated device values if the profile includes +calibration information.<br> +<br> +<br> +<a name="L"></a> The <b>-L</b> <i>klimit</i> parameter sets the black +channel ink limit for the CMYK separation, as a total percentage from +0% +to 100%. By default, this value will be estimated from the profile. For +printing press like devices, this can be used to prevent +the +black channel screening pattern "filling in". Typical values might be +from +95% to 99%. The ink limit +will be in final calibrated device values if the profile includes +calibration information.<br> +<br> +<br> +The <b><a name="p"></a>-p</b> option allows specifying an abstract +profile be applied to all of the output tables. An abstract +profile is a way of specifying a color adjustment in a device +independent way. The abstract profile might have been created using one +of the <span style="font-weight: bold;">tweak</span> tools, such as <a + href="refine.html">refine</a>.<br> +<br> +<br> + <br> +<br> +<br> +</body> +</html> |