Hi, I also noted that certain older manual lenses have their own color cast. Is there a way to have multiple colour profiles for camera's? Or a base color profile for the manufacturer lenses and enable lensprofiles for others?
Best, Gert On Thu, Jun 20, 2013 at 1:35 AM, Torsten Bronger <[email protected]> wrote: > Hallöchen! > > I followed > http://blog.pcode.nl/2010/06/28/darktable-camera-color-profiling/ to > get an input colour profile for the NEX-7. I have already sent the > RAW and the reference file to the DT developers, so I think they > will convert it to an enhanced colour matrix when they have the > time. However, this profiling was a daunting experience the > observations of which I'd like to share: > > 1. Calling colprof without the "-u" parameter means that the white > patch (with L=90.45 in my case) is converted to L=1 after the > colorin module. This makes the image brighter. However, the > standard colour matrix doesn't do this. Additionally, the base > curve cannot be applied anymore because the image gets way too > bright then. > > 2. Exporting with "colorimetric (absolute)" means that the white > patch becomes yellowish. All other colour intents work properly > as far as I can see. I have "always littlecms2" activated. If I > deactivate it, there is never a colour shift. > > 3. The quality of the ICC seems to be suprisingly poor. If I apply > the ICC to the original calibration image, I expect the values on > the patches to correspond with the values in the reference file. > For the patch "L19" (deep blue), the reference file says: (in > Lab) > > 12.62 39.19 -65.00 > > In Darktable, I get (after exposuring to the white patch L=90.45 > and chcking white balance): > > 18.6 19.3 -51.3 (matrix) > 17.5 18.4 -49.1 (shape+matrix) > 20.9 17.1 -51.2 (Lab cLUT) > 23.7 11.1 -47.2 (XYZ cLUT) > > If I use dcraw for applying the profile with "dcraw -4 -T -o > profile.icc DSC00001.ARW" (measured in DT): > > 15.3 28.9 -56.0 (for ALL profiles) > > Yes, I really double-checked that, the given profile file didn't > matter. WTF? If I give "-o 0" I get much worse values, and > without -o at all (i.e. standard Adobe colour matrix) I get > > 15.2 28.6 -55.6 (Adobe colour matrix) > > I find all these figures disappointing. And the LUTs performed > worst. And it is noteworthy that dcraw performes different from > DT with the same profile files, and better. > > So is it possible to get a reasonable (i.e. 5-10 times closer) > enhanced colour matrix somehow? If so, how? > > Tschö, > Torsten. > > -- > Torsten Bronger Jabber ID: [email protected] > or http://bronger-jmp.appspot.com > > > ------------------------------------------------------------------------------ > This SF.net email is sponsored by Windows: > > Build for Windows Store. > > http://p.sf.net/sfu/windows-dev2dev > _______________________________________________ > Darktable-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/darktable-users -- Panta Rhei -- Life is a dance ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ Darktable-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/darktable-users
