1. Measurement systems
Traces of measurement systems and measurement error at NBA ornaments
The creation of decorated bronze artefacts requires some kind of measurement system to secure an error-free application of the decoration. While examining the material of the Nordic bronze Age markers and recurring decorative units were detected that displays auxiliary lines and other kinds of markings that can confirm the construction of a decorative pattern. That such auxiliary tools, however, were not only used in constructing the large belt plates (with their many spiral rows), but also used in the crafting of other arteacts can be shown on several examples within the NBA.
The disc-headed pins from Lüneburg (LMH 12041) and Heitbrack (LMH 137:81), and on the Kolbedal tutulus (AM 5106) show a deep auxiliary line on which the dotted line is oriented. Not as clear, but still recognisable, is the auxiliary line visible on the disc-headed pins from Lower Saxony (12041 and 137:81).
Measuring units can also be carefully incorporated into the decoration of the ornament. Here, the notches or incisions might have served as guides as documented on the tutulus from Vejlbymark (FHM 0877) or the neck collars from Vellinge (Fyn, NM 25787), Sibberup (Sorø, NM B3574), Toppenstedt (Lower Saxony, HH62375) and Estrup (Sorø, NM 11969).
The construction of a star decoration on smal belt plates.
Errors in the construction of decorative pattern occurred frequently. On post-cast decorated bronzes these errors can be more often documented than on model-decorated artefacts. Some of the smaller belt plates under investigation revealed that the decoration had to be adapted due to measurement mistakes. Some characteritic features are for example that decorative elements, like triangles, deviates in their dimensions (see the image of the belt discs from Molzen (ML 242-84c) and Apel (LMN 4769).
In order to construct such a star-like triangle pattern successfully, the edge- and spike-accompanying circular lines were probably drawn as an orientation. Subsequently the triangle star-shape pattern was constructed using solid aid-lines to adjust the single triangles. The line-filling of the triangles was applied clockwise, in the same way as the line decoration around the spike.