Version:           2.0.0 (using KDE 4.6.4) 
OS:                Linux

Especially for beginners it would be handy if digikam supplied some presets for the demosaicing tool's luminosity curve.

The curve profiles should not only have the curve data but also a camera manufacturer tag in order for digikam to be able to automatically pick the correct preset depending on the camera the picture was taken with. For further infos relating the idea behind that feature see bug 276417.

Maybe this report can act as collection for those presets.

My first try for a luminosity curve that fits Nikon cameras:

RawCurveChannel0Point0=0,0
RawCurveChannel0Point1=2303,5462
RawCurveChannel0Point10=-1,-1
RawCurveChannel0Point11=-1,-1
RawCurveChannel0Point12=49663,62805
RawCurveChannel0Point13=-1,-1
RawCurveChannel0Point14=-1,-1
RawCurveChannel0Point15=-1,-1
RawCurveChannel0Point16=65535,65535
RawCurveChannel0Point17=-1,-1
RawCurveChannel0Point2=8703,16384
RawCurveChannel0Point3=-1,-1
RawCurveChannel0Point4=16895,32768
RawCurveChannel0Point5=-1,-1
RawCurveChannel0Point6=-1,-1
RawCurveChannel0Point7=29183,49834
RawCurveChannel0Point8=-1,-1
RawCurveChannel0Point9=-1,-1
RawCurveChannel0Type=0
RawCurveChannel1Point0=0,0
RawCurveChannel1Point1=-1,-1
RawCurveChannel1Point10=-1,-1
RawCurveChannel1Point11=-1,-1
RawCurveChannel1Point12=-1,-1
RawCurveChannel1Point13=-1,-1
RawCurveChannel1Point14=-1,-1
RawCurveChannel1Point15=-1,-1
RawCurveChannel1Point16=65535,65535
RawCurveChannel1Point17=-1,-1
RawCurveChannel1Point2=-1,-1
RawCurveChannel1Point3=-1,-1
RawCurveChannel1Point4=-1,-1
RawCurveChannel1Point5=-1,-1
RawCurveChannel1Point6=-1,-1
RawCurveChannel1Point7=-1,-1
RawCurveChannel1Point8=-1,-1
RawCurveChannel1Point9=-1,-1
RawCurveChannel1Type=0
RawCurveChannel2Point0=0,0
RawCurveChannel2Point1=-1,-1
RawCurveChannel2Point10=-1,-1
RawCurveChannel2Point11=-1,-1
RawCurveChannel2Point12=-1,-1
RawCurveChannel2Point13=-1,-1
RawCurveChannel2Point14=-1,-1
RawCurveChannel2Point15=-1,-1
RawCurveChannel2Point16=65535,65535
RawCurveChannel2Point17=-1,-1
RawCurveChannel2Point2=-1,-1
RawCurveChannel2Point3=-1,-1
RawCurveChannel2Point4=-1,-1
RawCurveChannel2Point5=-1,-1
RawCurveChannel2Point6=-1,-1
RawCurveChannel2Point7=-1,-1
RawCurveChannel2Point8=-1,-1
RawCurveChannel2Point9=-1,-1
RawCurveChannel2Type=0
RawCurveChannel3Point0=0,0
RawCurveChannel3Point1=-1,-1
RawCurveChannel3Point10=-1,-1
RawCurveChannel3Point11=-1,-1
RawCurveChannel3Point12=-1,-1
RawCurveChannel3Point13=-1,-1
RawCurveChannel3Point14=-1,-1
RawCurveChannel3Point15=-1,-1
RawCurveChannel3Point16=65535,65535
RawCurveChannel3Point17=-1,-1
RawCurveChannel3Point2=-1,-1
RawCurveChannel3Point3=-1,-1
RawCurveChannel3Point4=-1,-1
RawCurveChannel3Point5=-1,-1
RawCurveChannel3Point6=-1,-1
RawCurveChannel3Point7=-1,-1
RawCurveChannel3Point8=-1,-1
RawCurveChannel3Point9=-1,-1
RawCurveChannel3Type=0
RawCurveChannel4Point0=0,0
RawCurveChannel4Point1=-1,-1
RawCurveChannel4Point10=-1,-1
RawCurveChannel4Point11=-1,-1
RawCurveChannel4Point12=-1,-1
RawCurveChannel4Point13=-1,-1
RawCurveChannel4Point14=-1,-1
RawCurveChannel4Point15=-1,-1
RawCurveChannel4Point16=65535,65535
RawCurveChannel4Point17=-1,-1
RawCurveChannel4Point2=-1,-1
RawCurveChannel4Point3=-1,-1
RawCurveChannel4Point4=-1,-1
RawCurveChannel4Point5=-1,-1
RawCurveChannel4Point6=-1,-1
RawCurveChannel4Point7=-1,-1
RawCurveChannel4Point8=-1,-1
RawCurveChannel4Point9=-1,-1
RawCurveChannel4Type=0

NOTE: This curve works with highlighting set to anything but "solid white".
To try it you have to quit digikam and edit your ~/.kde4/share/config/digikamrc in the [RAW Import Settings] section.

Reproducible: Didn't try