Seite - 66 - in The Vienna Genesis - Material analysis and conservation of a Late Antique illuminated manuscript on purple parchment

66 The parchment of the Vienna Genesis: characteristics and manufacture product is often very thick and oily. However, epidermis membrane is used for the repair of holes in the parchment. Very thin folios can be found in manuscripts containing parchment of irregular qualities. Some steps in the preparation of parchment, including the splitting of sheepskins, appear to be preserved in a modified form in the Late Byzantine period. The quality of these random examples cannot be compared with the high level of production in Late Antiquity. In contrast, the techniques of peeling sheep skin completely disappeared in the preparation of parchment in the Western and Northern part of Europe in early medi- eval times. Natural holes were not repaired with patches made from the epidermis layer of the skin. As the epidermis layer was not removed, the medieval parchment was thicker and stronger than Late Antique parchment. Holes could be closed by sewing with thread. The parchment of the Vienna Genesis was manufactured by the same method as most other manuscripts that survive from Late Antiquity, whether they were dyed or remained in their natural colour. The parchment of the Codex Rossanensis and the Codex Sinopen- sis closely resemble the parchment of the Vienna Genesis. The parchment of the Vienna Dioscorides was also produced using the same technique yet the material was less well selected and shows more differences. The quality of the parchment in the Vienna Dioscor- ides more closely resembles that of manuscripts of the later Byzantine period. Summary and conclusions for conservation The parchment of the Vienna Genesis shows typical features of Late Antique manufac- ture: thinness, smoothness and an equal appearance of the hair and flesh sides. Similar properties were reproduced during the production of new parchment by removing the epidermis layer from the hair side of sheepskin. The parchment of the Vienna Genesis was carefully selected and shows the expert skills of the Late Antique parchment makers. By visual observation, practical experiments and comparison with other contemporary manuscripts, the writing support was identified as sheep parchment that was made from the skins of young animals. One or two bifolios were cut from a single sheepskin. A com- parison of the parchments has confirmed the close relationship of the Vienna Genesis with the Codex Rossanensis and the Codex Sinopensis. The exposure to high humidity, multiple restoration treatments and more than one hundred years of storage between glass and polyacrylate has greatly altered the parchment of the Vienna Genesis. The folios have become more transparent. The application of parchment glue to both sides of the folios and subsequent flattening have changed the surface texture. Finally, the lengthy storage between rigid sheets of glass and polyacrylate has altered the behaviour of the parchment by preventing its natural movement. Open-Access-Publikation im Sinne der CC-Lizenz BY 4.0