Page - 157 - in The Vienna Genesis - Material analysis and conservation of a Late Antique illuminated manuscript on purple parchment

Sophie Rabitsch, Antonia Malissa, Katharina Uhlir, Martina Griesser, Christa Hofmann 157 preliminary investigations of micro samples of the original silver ink with energy dispersive X-ray analysis in the scanning electron microscope (SEM/EDX) performed by Rudolf Er- lach and with micro-X-ray diffraction (µ-XRD) performed by Klaudia Hradil, see chapter on silver inks. Micro samples were taken by slightly scraping the surface of the ink with a scalpel. According to the results of SEM/EDX, the metal used for production of the silver ink may have been pure silver. If small amounts of copper had been present in the metal originally, this would most likely have been removed due to the corrosion process. The detected silver is always accompanied by chlorine, a clear hint for the presence of silver chloride. µ-XRD detected the main crystalline phase silver and various corrosion products, i. e. silver chloride (AgCl; chlorargyrite), silver oxide (Ag2O) and silver nitrate (AgNO3). The results of these measurements indicated that the ink analysed is a pure silver ink with silver chloride as the main corrosion product. Due to these preliminary results, recipes for the production of pure silver inks as well as for silver inks with metallic and non-metallic additives were chosen for the first sub study. The selection of recipes used for sub study 2 was based on the results of further analysis of the Vienna Genesis’ silver ink using µ-XRF in the second year of the project, see chapter on silver inks. Representative measurement points were chosen on different folios of the manuscript. The XRF spectra generated indi- cated a more significant amount of copper than it was initially presumed due to prelimin- ary analyses, with copper being more likely a minor component of the ink. Additionally, an almost constant ratio between silver and copper could be observed for the silver ink of the entire codex. Whereas sub study 1 mainly focused on the corrosive impact of different inorganic and organic ingredients, the effect of copper was investigated within the second sub study. An overview of the reference inks and the exact name of the recipes according to Trost as well as a summary of the categories of silver inks and the additives used are given in Table 1. Table 1: Overview of the reference inks, the exact name of the recipe templates according to Trost, a summary of the different categories and the used additives. Reference ink Recipe Group Additives ST1 CL N 3–13 Silver ink with additional components Sodium chloride (NaCl), copper(I)oxide (Cu2O, copper hair) ST2 MC LXXXXII d Pure silver ink - Open-Access-Publikation im Sinne der CC-Lizenz BY 4.0