I have been trying various editors with old photos, and I’m getting more comfortable with Darktable, at least for landscapes. The curious bit with this case was that I ended up using the Base curve preset (camera profile) “Nikon alternative” instead of one for Olympus, even though this RAW was from an Oly camera. At least Darktable lets you apply camera profiles from different camera brands, which is really unusual. I am disappointed in the Darktable tool for exporting to a JPG file. It does not provide for adding a watermark or for sharpening. So I used Paint.net on the final JPG to take care of those tasks.