Hi guys and thanks for your replies.
@alan: They are definitely different. If you import the files to LR and push up the exposure by 1-2 stops, you'll see a clear difference.
@steve: I'm not an expert on image files, so I'm not fully sure how to interpret your posts, but I think you are saying that the pictures are different and LR is treating them consistently. This is fair enough, but does not solve my problem, since:
I'm not arguing that LR is doing something intrinsically wrong. I'd rather say that it is doing something different then the Olympus software and that the latter gives "correct", in the sense of consistent, results.
I created four more files and uploaded them to
https://pitufos.de/ORF/. The jpegs with the original file names are produced via:
ORF-file -> Import to LR -> push exposure 2 stops -> export as JPEG
The second one appears much more yellowish. Looking at the histogram, it seems like the blue curve is shifted to lower brightness.
The second pair, named a and b, respectively are produced via:
ORF-file -> Open in Olympus Viewer 3 -> export as TIFF -> import TIFF in LR -> push exposure 2 stops -> export as JPEG
This pair looks identical to me. But I consider this method a workaround at the best.
I also tried dcraw to process the files and couldn't find any differences in colour either.
In summary: Even though it might be that the ORF files are different, there must be something (maybe the black level value) that allows the Olympus viewer and dcraw to create consistent results. Therefore, even if LR is not technically doing something wrong, I would argue that the result is incorrect. If that is due to a problem in ORF, then I guess LR needs to work around this and do the same "magic" that the Olympus Viewer does to give consistent results.
Side note: I don't have a problem if different raw converters give slightly different colours in the end. But they should give consistent results in a series of pictures of the same scene. And this is not entirely random when using LR. P...73.ORF looks consistent to P...71.ORF and so do the next 5 pictures. And then come another three, consistent with P...72.ORF and then back to P...71.ORF and so on and so forth... . Quite frustrating.
Regards
Stephan