<br><br><div class="gmail_quote">On Mon, May 16, 2011 at 7:56 PM, Alastair M. Robinson <span dir="ltr"><<a href="mailto:blackfive@fakenhamweb.co.uk">blackfive@fakenhamweb.co.uk</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Hi,<div class="im"><br>
<br>
On 16/05/11 18:14, Jan-Peter Homann wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
What is the advantage to profile the printer in RGB-mode, if gutenprint<br>
allows it to do in CMYK ?<br>
</blockquote>
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Why enforce a colour space at all? Encourage the use of one over another by all means, but don't arbitrarily disallow a colourspace unless you have *very* good reason.<br>
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It's much easier to create a good RGB profile than it is a good CMYK profile; for an RGB profile there's just the three-dimensional colour space to worry about. For CMYK you not only have to sample four dimensions, which requires way more patches, but you also have to consider total ink coverage and black generation functions.<br>
<br>
A good CMYK profile may give slightly better results than the canned RGB -> CMYK conversion in the driver (in some cases maybe significantly better, but Gutenprint's RGB->CMYK is pretty good), but the extra effort required to get there will make it less likely that we'll be able to crowd-source profiles.<br>
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All the best<br>
--<br><font color="#888888">
Alastair M. Robinson<br>
</font></blockquote></div>Yes, I did some experiments with CMYK profiles in the past, and got ok, but not superb results. On the other hand a handheld ColorMunki will do decently for RGB profiles, but in my opinion if you really want a good CMYK profile you need to read a few thousand patches and to do it reliably and without fatigue you should resort to scanning spectro; also the software may or may not be an issue. I have had good results with RGB profiles for Gutenprint, which are quite close to those supplied by Epson for the native drivers, and so I see no reason to introduce additional complexity at this stage of the project. <div>
<br></div><div>Edmund</div><div><br></div>