Nave, northern and southern wall, fragments

The plaster is rough and very hard; perhaps it was consolidated during restoration. The fact that limewash was applied over it has been confirmed by the cross-sections of the samples taken (Figs. 1–2). The plaster appears bright, mostly containing angular, translucent aggregate grains (Fig. 2), though it also includes some dark sand grains (Fig. 1). The plaster samples from the northern and southern walls have been analysed using the XRD technique to determine whether the two fragments belong to the same mural. Both samples show the presence of quartz, calcite, and dolomite, as well as some feldspars. The sample from the northern wall mostly consists of quartz as the aggregate, while the binder content is somewhat more modest. Both calcite and dolomite can be used as binders, and both can also be crushed into the aggregate (translucent grains). The northern wall sample contains more dolomite than calcite. In contrast, the sample from the southern wall contains remarkably little quartz but an abundance of calcite and dolomite, of which the latter is once again prevalent. Based on the XRD analysis, it appears that the plaster on the southern wall differs from the one on the northern wall, suggesting that the fragments belong to two separate murals. Regardless of the relative amounts of the plaster ingredients, we should underline that they are identical in both samples and especially that the proportion between the calcite and dolomite is similar. In medieval mural plasters, dolomite was relatively rare compared to calcite. Thus, despite the differences in the quantity of the ingredients on the two walls, this could nevertheless be a single mural, which could be confirmed by further analyses. On the other hand, the murals may also be two separate works, but the materials could have been obtained from the same location.

Chancel, southern wall, fragment

In the chancel, limewash was also applied to the rough plaster. The cross-section only reveals the limewash, which has fallen off, and a yellow colour layer (Fig. 3). The XRD analysis of the sample reveals an extremely high content of dolomite, much less calcite, and an extraordinarily low quartz content. Feldspars are also present. The plaster is therefore made of lime (calcite and/or dolomite) and crushed dolomite or marble with a bit of quartz. The ingredients are identical to the mural fragments on the two nave walls, but the proportions are notably different from the samples taken in the nave. Due to its modest quartz content, the analysed sample is more similar to the sample from the southern nave wall. We should underline the significant presence of dolomite, which is also present in the nave, as a rarer medieval plaster ingredient in the territory of today’s Slovenia. Based on the results, it is impossible to either confirm or deny that the mural in the chancel was painted at the same time as the ones in the nave. It is possible that the nave and the chancel were painted simultaneously, or the murals might originate from different periods while the materials could have been sourced from the same place. It would be interesting to investigate the potential nearby dolomitic rock deposits.