[argyllcms] Re: -S command in Colprof for printer profiles
- From: Gerhard Fuernkranz <nospam456@xxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Tue, 18 Oct 2011 22:27:00 +0200
Am 18.10.2011 19:32, schrieb Alan Goldhammer:
It's likely that I'm a little dense on this but I've read Graeme's
documentation over multiple times regarding the use of this command and gamut
mapping. I want to make a profile for my printer and I've printed patch
targets and read them. How do I handle '-S' when I'm ready to run Colprof? We
don't know what the gamut behavior of the printer is at this point only from
research that it's broader than AdobeRGB1998 and smaller than ProPhoto.
ProPhoto is the default color space for Adobe Lightroom and the recommended
color space for Photoshop because of the larger gamut than AdobeRGB1998. Does
this mean that I should use '-SProPhoto.icc' in my command line or use '-nS'.
It's not clear to me and assistance would be appreciated.
If you want the perceptual and saturation intents of the profile to do gamut mapping from
ProPhoto's gamut to the printer's gamut, then you should use -SProPhoto.icc. This means
that the perceptual intent of the profile will compress the ProPhoto gamut hull until it
can be completely completely enclosed by the printer's gamut hull. This compression
affects however _all_ colors inside the gamut. If the gamuts of many of your _actual
images_ happen to be smaller than the ProPhoto gamut, then consequently the perceptual
intent of the printer profile may de-saturate many of your images unnecessarily, just in
order to be prepared to render any worst case images (utilizing the _full_ ProPhoto
gamut) w/o clipping.Choosing a reasonable "one size fits all" source gamut is
always a trade-off.
Regarding '-nS', I would expect that -nP and -nS don't have any effect if the
-S... profile is a matrix profile.
Btw, if the gamut of your printer is really as large as you assume, then I'd
possibly even try to print with relative colorimetric intent and don't care
about gamut mapping at all (I do have doubts though, that the printer's gamut
hull really encloses the Adobe RGB gamut hull completely, for instance is the
printer's black point really as dark as Adobe RGB black?).
Regards,
Gerhard
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