Page - 195 - 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 195 and therefore a better condition of the samples compared to the samples of the reference parchment NP. In contrast to the fibre samples of the artificially aged reference samples, the fibre sam- ples of the Vienna Genesis contained a smaller amount of fibres. With regard to the fibre morphologies, sample Vienna Genesis_S1, which was taken from folio 2, mainly showed “bundles” and partly gelatinised fibres, whereas in the fibre sample Vienna Genesis_S2 from folio 9 mainly “flat fibres” (Fig. 39 a) and “pearls on a string” (Fig. 39 b) were present. When comparing the information gained by the analysis of the fibre morphologies of the reference samples as well as the fibre samples from the Vienna Genesis with the deter- mined values of the shrinkage temperatures (Table 4), they confirm one another. Summary and conclusions A number of 14 reference inks was prepared for the artificial ageing study. The inks ST1– ST9 were artificially aged during the sub study 1 and ST10–ST14 were part of the sub study 2. The observations which were made during the preparation of the reference inks as well as the results of the analyses performed on the reference samples showed that it requires a lot of knowledge and practice to properly prepare silver inks and to write with them. Since the instructions in the original treatises are often not very precise, the inter- pretation of a single recipe can vary greatly. Even the question of the silver source con- stitutes a factor with many unknowns. Craftsmen preparing silver inks could have used pure silver with traces of other elements depending on the mine, silver alloys or recycled silverware. Certain preparations were modified in order to be able to write with the inks on the parchment. Nevertheless, for some inks it was not possible to apply them smoothly, as the silver powder either did not disperse in the binder or the inks were too thick or clotted. Additionally, the majority of the reference inks tended to smear or flake off during the burnishing process. Only three reference inks (ST5, ST7 and ST10) could be burnished without problems66. The unburnished inks mostly had a greyish colour without a silvery shine, while the burnished ones had shiny silver surfaces. The colours of the reference inks ranged between yellowish, greenish or brownish grey and a very light grey on purple parchment. Most of them were at least a bit glittery when being observed under magnification. The tests showed that the refining method of the silver powder influences the usability of the inks. The reference inks which were prepared with silver powder gained by grinding silver leaves by hand with gum arabic were easier to 66 These observations were not congruent with the observations of Trost. Open-Access-Publikation im Sinne der CC-Lizenz BY 4.0