Cyanotype is an old photographic printing process that produces each time slightly different results of the same negative. If they are toned as it is the case here with tannin acid solution the kinds of variations increase. Partly for me that‘s the charm of this method which was discovered in 1842.
„Christine Tippelreiter #077”
„Wolfgang Sammer #078”
„Veronika Wandl #076”
More about the technical and historical aspects of this process at Wikipedia.