Scratches? Scribbles? Scripture! Revealing the Unseen – 3D Scanning of Glagolitic Graffiti of the 10th Century at the Monastery of St. Naum

The Monastery of Saint Naum in Macedonia is part of the UNESCO World Heritage Site “Natural and Cultural Heritage of the Ohrid region”. The area is unique not only for its architecture but also its outstanding linguistic heritage. The monastery was named after Saint Naum and founded at the end of the 9th century and is visited by many tourists every day. In the transition from the narthex to the central church, the visitor immediately notices two shiny white marble columns. These columns carry unique inscriptions/graffiti, which represent some of the earliest evidence of the Glagolitic alphabet, a precursor of the Cyrillic alphabet. During the project, previously unseen inscriptions were revealed on the columns. The huge number of tourists poses a danger to the historic surfaces of the columns, as the constant touching and rubbing of the inscriptions is causing deterioration. Therefore, there is an urgent need to image and archive the inscriptions. Using macrophotography with raking light did not work well as the columns’ curvature and shiny surface caused blurring in the images, and some of the graffiti were not visible. Therefore, a structured light scanner with a 3D point resolution of 30 μm or less was used to record the columns, to both preserve and reveal these unique graffiti. The recording of the surfaces was deliberately carried out without texture information to exclude errors caused by the shiny and discoloured marble of the columns. The resulting high-resolution 3D model can be virtually illuminated from any angle, for example using raking light, allowing detailed observations and analysis. In addition to digitally preserving and archiving the inscriptions, the resulting surface models can be easily accessed by Slavistic and linguistic experts for a variety of research purposes.