On Fri, 13 Jan 2012 22:51:09 +0100, Paolo Avezzano <info@xxxxxxxxxxxxxxxxx> wrote:
After a number of test with quite a few combination of settings and just poor results on grey gradient and patches I decide to give up for now.Sorry to say that but i1Profiler "just works", as Steve would have said.It may not be the best calibration overall, but it's predictable and good in quality.Back to Lightroom...
I've run another round, listening to previous suggestions and thus adding -A 0.1 -H -V to dispcal.
In the meantime I'm learning of more and more bugs in what's supposed to be professional software... Lightroom renders differently photos when I open them full screen in loupe and when I run the slideshow (hell, I was using it for quickly subjective evaluation of a test gallery).
In any case, with this round the profile to use is the one with colorprof -v -qu -ni -no -as ; LUT based profiles now show lots of banding and even visually some photos are ruined by abrupt transitions in saturated values. The picked profile, on the other hand, is excellent in neutrality for dark grays, surpassing i1Profiler; even details in shadow are excellent, since bands are visible all the way up to #1. This seems to require to me to make further adjustments to existing photos, that now show a few more details in shadows that I'd like. But I suppose they were badly tuned earlier, since I think it's clear that a profile which all the dark gray bands visible is better.
Also the Granger rainbox looks very well now, with no significant artifacts (the strange color patches I see with the previous profile so weren't due to "imaginary colors", but to poor quality).
The big surprise has been for saturated colors (I think due to the -V). I think I've never seen such colors with my display, in the past four years also with different software and colorimeters. It seems that Argyll is taking a wider gamut out of it. Note that while LUT profiles are again bad, with clearly burned out saturated colors, the picked profile seems fine.
The quality in shadows seems to be confirmed by an objective evaluation: if I look at the shape of the gamut with the Mac OS X tool, in the xyY space, both Argyll previous profiles and i1Profiler show a sort of "foot" near shadows; I mean that while the "walls" of the gamut come down vertical, when they reach the floor they solid gets suddenly "expanded". Looks like a bad control of maths in corner cases. The latest profile has no problems here.
Pending further investigation about saturated colors, this seems to be the best profile so far, beating i1Profiler.
I think I'll start posting details to my blog (images that I'm using a samples are available too (*)), if someone in the meantime wants the detailed report let me know.
(*) Question. Images are available as part of my galleries, but converted to sRGB, so they are probably good to figure out the kind of evaluation I'm doing, but not to try to reproduce details. II think it makes sense that I export a copy in JPG with the ProPhotoRGB profile, right?
-- Fabrizio Giudici - Java Architect, Project Manager Tidalwave s.a.s. - "We make Java work. Everywhere." fabrizio.giudici@xxxxxxxxxxxx http://tidalwave.it - http://fabriziogiudici.it
