Seite - 26 - in The Vienna Genesis - Material analysis and conservation of a Late Antique illuminated manuscript on purple parchment

26 The history of the Vienna Genesis and former interventions since 1664 the miniatures50. Wächter learned about the use of parchment glue during internships in Italy at the institute “Istituto Centrale Patologia del Libro”, today ICRPAL, and at the con- servation department of the Vatican library. In an article on the conservation of the Vienna Dioscorides Wächter admits that the addition of 1 % vinegar to the parchment glue is con- troversial. The solution becomes less viscous with the addition of vinegar. The leaves of the Vienna Dioscorides were moistened with ethanol, then rectified by stretching and spraying with parchment glue. Tears were closed with gold beater’s skin51. When Hilde Kuhn treated the folios of the Vienna Genesis, she probably also sprayed them with parchment glue con- taining vinegar to flatten the parchment and to stretch deformations. She might have dried the parchment under weights instead of stretching it on a frame. Pressed folds can be ob- served on some folios. Gold beater’s skin was used much less frequently, if at all, than on the leaves of the Vienna Dioscorides. Many folios show mending of tears with paper fibres (Fig. 10). The method of mounting degraded folios of parchment between polyacrylate was also used for the parts of Tabula Peutingeriana (Codex 324) and the folios of the so-called black prayer book (Horarium Galeazii Mariae Sfortiae V. ducis Mediolanensis, Codex 1856). 50 Wächter, 2003, pp. 36–37. 51 Wächter, 1962, pp. 24–26. Fig. 10: Mending a tear with paper fibres on folio 1, page 1. Open-Access-Publikation im Sinne der CC-Lizenz BY 4.0