Infrared reflectography (IRR) images were captured with an Apollo reflectography camera (Opus Instruments, UK) from Ars nova music fragments preserved in Nuremberg, Stadtbibliothek, Germany (12–13 Februrary 2020, and 18 October 2021), and Melk, Stiftsbibliothek, Austria (21 October 2021). The aim was to verify the presence of carbon in the inks.

The regular Short-Wave Infrared (SWIR) sensing range (900–1700 nm) of the 128×128-pixel scanning InGaAs sensor was reduced by a Long Wave Pass Filter (LWP1510, range 1510–1700 nm), mounted in front of the IR lens (150 mm, f/5.6–f/45) with the aperture of f/8, acquisition time was 50 ms/tile. The working distance between the sensor and the object was set to approx. 73 cm in Melk, and to approx. 80 cm in Nuremberg. Broadband illumination was provided by two 20W halogen lamps.

The research for this publication was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany´s Excellence Strategy – EXC 2176 'Understanding Written Artefacts: Material, Interaction and Transmission in Manuscript Cultures', project no. 390893796. The research is part of project RFA08 and was conducted within the scope of the Centre for the Study of Manuscript Cultures (CSMC) at Universität Hamburg.