Hallöchen! Marie-Noëlle Augendre writes:
> [...] > > Currently, I'm obliged to deactivate the basic curve as all my > images seem to picture lobsters instead of tennis players (or > whatever people I'm shooting): all the skin tones are very, very > red. For my camera, the enhanced colour matrix intensifies reds, too, compared to the standard matrix. But my own measurements confirmed this. Well, they make deep reds darker. But skin tones are practically untouched. And yes, the basecurve intensifies some already intensive colours even more. Sometimes, removing the leftmost point of the basecurve helps -- just drag it out of the plot to the left. But: I played around with it now, and find the basecurve's behaviour a little bit suspicious. I don't know whether this is intended behaviour though. Steps to reproduce: 1. Download https://bob.ipv.kfa-juelich.de/bronger/nex7_calibration/DSC02310.ARW 2. Import this RAW in DT. 3. Set up colour picker areas on patches L17 (red) and GS23 (black). Use the "RGB" mode to display values. 4. Now switch on and off basecurve and see how the green channel value is mapped from similar values to totally different values by the basecurve. Now, this may simply mean that I have not understood what basecurve actually does. I thought it was applied as a tone curve to the RGB channels separately. But this clearly is here not the case. Interestingly enough, there are three ways to eliminate this odd mapping: * You may switch the input profile from any matrix (standard or enhanced) to linear RGB. * You may switch the display profile from sRGB to linear. * You may remove the lowest control point of the basecurve. The latter two make me think that it is some sort of rounding error. The green value is clipped to zero, and the sRGB gamma cannot recover it anymore. So, is it a bug? Tschö, Torsten. -- Torsten Bronger Jabber ID: [email protected] or http://bronger-jmp.appspot.com ------------------------------------------------------------------------------ See everything from the browser to the database with AppDynamics Get end-to-end visibility with application monitoring from AppDynamics Isolate bottlenecks and diagnose root cause in seconds. Start your free trial of AppDynamics Pro today! http://pubads.g.doubleclick.net/gampad/clk?id=48808831&iu=/4140/ostg.clktrk _______________________________________________ Darktable-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/darktable-users
