hi, that example image is totally not dark saturated enough blue to trigger the Lab conversion turns purple colourspace problem (which is solved by the gamut clipping, as roman mentioned). i suppose you could try to measure a basecurve from a CR2/jpg pair for that camera [0], that affects colour saturation a lot, too.
cheers, jo [0] https://github.com/darktable-org/darktable/tree/master/tools/basecurve On Sat, Jan 16, 2016 at 10:24 AM, gersch...@gmail.com <gersch...@gmail.com> wrote: > On 09.01.2016 09:21, Roman Lebedev wrote: >> On Sat, Jan 9, 2016 at 1:49 AM, gersch...@gmail.com <gersch...@gmail.com> >> wrote: >>>>>>>> blue colors in the raw files of my Canon 700D are turned into much >>>>>>>> darker blue or purple >>>>>>>> in darktable when applying the usual corrections (sharpen, >>>>>>>> orientation, base curve). The >>>>>>>> jpg files produced by the camera show a blue which is much closer to >>>>>>>> the real color. >>>>>>>> Is this a known problem? What Is the best way to correct this? I have >>>>>>>> the impression >>> that >>>>>>>> this does not occur in rawtherapee. >>>>>>> >>>>>>> Yeah, this problem has been present for quite some time. I see it in >>>>>>> shots taken with >>> my Canon 60D >>>>>>> but not in those taken with my 5d3. It's cased by the input color >>>>>>> profile; try >>> changing the profile >>>>>>> from "enhanced color matrix" to "standard color matrix" or even >>>>>>> "rec2020". >>>>>>> >>>>>>> The ultimate solution is to profile your camera using a color target: >>>>>>> >>>>>>> https://encrypted.pcode.nl/blog/2010/06/28/darktable-camera-color-profiling/ >>>>>>> >>>>>>> Darktable used to accept these custom profiles for inclusion in the >>>>>>> main project, but >>> this is >>>>>>> currently not happening pending a rework on the way the input end of >>>>>>> the pipe works >>> (though I don't >>>>>>> remember the details). None of this stops you using your own custom >>>>>>> profile, though. >>>>>> >>>>> >>>>> Thanks for your information. I've tested different input color profiles >>>>> but I still have >>>>> the impression the blue is too saturated. >>>>> Is there someone with a Canon camera who would share their optimised >>>>> color profile or >>>>> darktable style? >>>> Have you already tried setting "gamut clipping" in "input color >>>> profile" to "linear Rec2020 RGB"? >>> >>>> https://www.darktable.org/usermanual/ch03s04s03.html.php#d0e7524 >>> >>>>> Thanks also for the hint to try RawStudio profiles. >>> >>>>> Regards, Gerd >>>> Roman >>> >>> Hi, >>> yes, I tried Rec2020 RGB with gamut clipping but now all colors look rather >>> pale. I think >>> that the colors in the standard color matrix look good except the blue >>> being too dark. >> Just to be sure: i meant: in "input color profile" module, set "gamut >> clipping" to "linear Rec2020 RGB". >> Not: in "input color profile" module, set "profile" to "linear Rec2020 >> RGB". >> >>> Regards, Gerd >> Roman. > > Hi, > > I've actually found a photo where the blue color situation of Canon raw files > can be seen > very well: > Have a look at > https://www.dropbox.com/s/8ikzw34pcvpstqf/IMG_7993.CR2?dl=0 > https://www.dropbox.com/s/ykhmyu12c9o89sa/IMG_7993.JPG?dl=0 > > The real color of the shirt is very close to the blue in the JPG but it > appears to be > purple in the raw image if the standard base curve is applied. The setting > suggested by > Roman improves the color a bit but not enough. > > Regards, Gerd > > > > > ------------------------------------------------------------------------------ > Site24x7 APM Insight: Get Deep Visibility into Application Performance > APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month > Monitor end-to-end web transactions and take corrective actions now > Troubleshoot faster and improve end-user experience. Signup Now! > http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140 > _______________________________________________ > Darktable-users mailing list > Darktable-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/darktable-users ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140 _______________________________________________ Darktable-users mailing list Darktable-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/darktable-users
