## 4 Conclusions  
For the first time, pigments and binding media from Heddal and Eidsborg stave church were characterized by a multi-technique approach. In addition, information related to the conservation condition of the painting material was obtained. Pigment analysis presented in this study confirms the presence of ochre and chalk used in both Heddal and Eidsborg, with the XRD patterns confirming the presence of hematite as the main red pigment. Hematite was found to be coupled to the more precious minium in a few samples and in very different proportions between the two churches. While only traces of minium were found in two untreated samples from Heddal, quite high relative amounts were detected in the only consolidated sample in poor conservation condition taken from Eidsborg (E3a). EDS, FTIR and XRD analysis revealed the similarities between the elemental constituents found at Heddal and Eidsborg, whilst simultaneously emphasizing the subtle differences found in the clay components of the red pigments. These results suggest the use of different raw materials and/or different artists' recipes within the two sites. Binding media analysis identified the presence of a proteinaceous material, i.e., animal glue, in all samples using GC-MS and FT-IR, with ELISA identifying fish glue in all tested specimens. Overall, these results concluded that distemper (i.e., animal glue-based paint) was used as the main technique in the naive of Heddal and Eidsborg; however, the use of oil was also identified. Within Heddal, this secondary binder was most likely used during past interventions. On the other hand, it was not possible to distinguish the original glue-based binder from the consolidant (sturgeon glue). Additionally, IR and GC-MS analysis showed the presence of wood and/or wood-related products through the paint layers, signifying that the wall planks are contaminating the pictorial image. When examining the current preservation state of these two sites, XRD analysis of the white basecoat from Heddal showed evidence of ongoing alteration phenomena. In particular, the amount of weddellite was found to increase when moving from the left to the right of Heddal's northern nave wall. Furthermore, when examining the common painting materials (i.e., pigments and binders) used at these two sites, differences were mainly found in consolidated areas that were in poor condition (E3a and H3a). On the basis of the obtained results, we can presume that these areas would have been retouched during the 1920s and 1950s, for Eidsborg and Heddal, respectively. The specific mechanism of damage is uncertain; however, water seems to be the main contributing factor. Due to the inherent property of glues readily absorbing water, the most common cause of damage to distemper paint is due to environmental moisture or liquid water. It can facilitate the migration of mobile components, as well as the re-solubilization of the binder, which could ultimately weaken the cohesive and adhesive properties of the paint. Additionally, as the stave church's building envelope is not airtight, direct exposure to water is not uncommon; water damage was observed at both sites (e.g., dark shields or tide lines) during the 2000s consolidation campaigns. Thus, the results presented in this paper represent the foundation for ongoing research for the preservation and conservation of these unique and fragile artworks. In conclusion, the presented paper aimed to provide a complete characterization of the materials constituting distempered paintings as well as alteration products of Heddal and Eidsborg stave churches through a multi-technique approach. The investigation focused on both the inorganic and organic fractions of the historic material and results clearly demonstrate the necessity of applying different analytical techniques to solve issues related to the identification of such complex mixtures.