[Openicc] Printing targets: App or driver ?

[edmund ronald]

On Mon, May 16, 2011 at 7:56 PM, Alastair M. Robinson <
blackfive at fakenhamweb.co.uk> wrote:

> Hi,
>
>
> On 16/05/11 18:14, Jan-Peter Homann wrote:
>
>  What is the advantage to profile the printer in RGB-mode, if gutenprint
>> allows it to do in CMYK ?
>>
>
> 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.
>
> 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.
>
> 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.
>
> All the best
> --
> Alastair M. Robinson
>
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.

Edmund
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