Looking under the skin: multi-scale CT scanning of a peculiarly constructed cornett in the Rijksmuseum

Covered tightly by a thin leather skin, three early seventeenth-century cornetts from the collection of the Rijksmuseum were examined with the focus on their construction and manufacturing. One cornett of the three unexpectedly turned out to have a peculiar construction and to be made out of two sections of different wood species. The question arose whether this could be original or is the result of an extensive restoration. As the internal structure is not accessible for analysis and examination, multi-scale Computed Tomography (CT) scanning was employed to identify the exact regions of interest (ROI) and subsequently perform scans at a sufficiently high resolution in those areas. 3D images of the hollow spaces such as the tunnelling structure caused by the common furniture beetle (Anobium punctatum) criss-crossing the wood species could be computed from the 3D x-ray tomography reconstruction. This allowed to place the occurrence of the insect infestation after the joining of the two sections. Fine tool-marks, signs of construction and potential indications of earlier treatments could be visualized. These results were compared with the other two instruments of the same group and cross-referenced to instruments in other collections, in an attempt to answer questions about the instrument’s authenticity and originality. While the unusual construction out of two wood species might be the result of an extensive repair, another possible hypothesis—based on the combination of the results—is that this unique choice of original manufacturing was intentional, possibly to avoid splitting of the wood when inserting the mouthpiece or to counteract undesired vibrations when played.

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