Thanks for the offer, Martin. What would you do about it? I set the black and white point at default, but the gamma at 0.2. It needs a very precise adjustment I noticed. Also tried a negative black point, but after so many variables changed I couldn't see the 'trees among the forest' any more.
I rendered another version this morning, and got quite frustrated about tiny specks in the snow. Couldn't get rid of it somehow. Made a fresh pure white surface layer, and even there the ******* things turned up. See this image. BUT! As I am typing this, on my other machine I keep on testing, and found the culprit. It was the clouds! Too low quality. So in a couple of hours I will update this image.
---Dune