This is a straight scan. I cropped maybe 10% of the left side trees and the top clouds only.
Most of what seems to be dust (on the water) is actually on the water surface.

Franka Rolfix Jr., Frankar Vario 1:4,5 f=105mm, Ilford HP5+

The camera is here

Another image from this camera is here.

I have to keep reminding myself that this old folding camera and its lens were both built before 1951.