Thanks to all for the input! I think we can "close" this "case" by now. I think the issue is related to three things based on all of your input:
- First and foremost, I think Reala is simply a slightly more grainy 100 ISO film than some others, meaning results at such high scanning resolutions simply are looking worse than with other films.
- Bad film due to long and bad (non-cold) storage, causing the "oiling out" issues as described by PE and possibly also "air" bubbles.
- Grain aliasing as caused by scanning at higher resolution than the film "supports" and possibly in combination with forgotten to switch of USM in Flextight software, although I am pretty sure I did, see below.
To give some last feedback on useful comments by others:
I know this is on the brink of Hybridphoto, sorry for that, in hindsight it may have been better to post specifically in the "Hybrid Photo" social group here on APUG, BUT I needed the good "film knowledge" as well of persons like PE, to exclude or confirm a major film issue. These are the difficult questions to put in the right place, on Hybrid Photo, I may not have had enough input...