Fig. 8From: Conservation issues and chemical study of the causes of alteration of a part of the Stave Church in Hopperstad (Norway)Extracted content of each element in samples M1 and M4–M7. All the samples from the white substance have a high amount of calcium. The bird dropping sample, M1, has a higher amount of phosphorus than the other samples. Sample M6, from the exterior door, has a higher amount of all the elements, compared to the other samples with white layerBack to article page