More Darktable efforts

Installed DT 1.6 using the PPA for Ubuntu 14.10 : went perfectly fine.

Processed a few shots taken both with and without the Pentax K-r "Highlight Correction" and "Shadow Correction".

Supposedly the Shadow correction only affects JPEG (I was shooting RAW only).  But the Highlight Correction definitely underexposes the picture by 1 stop (by setting the base ISO to 200).  The JPEG preview is automatically compensated for this but Darktable doesn't seem to support and a +1 EV exposure compensation has to be applied during RAW development to get to the same kind of exposure as when this Highlight Correction stays off.

I then processed a RAW from the E-PM1 that had been severely overexposed during the shoot.  Applied about -1.0 exposure compensation and the highlight recovery modules in DT and the results were much better than what I could get from the JPEG (from the camera, this was a RAW+JPEG shot).  Especially when it comes to skin tones.

SO the conclusion would be: disable Highlight Correction if shooting RAW (saves manual compensation during development, and compensation can still be applied manually on the really badly overexposed ones with some kind of success even without this.