Seite - 277 - in The Vienna Genesis - Material analysis and conservation of a Late Antique illuminated manuscript on purple parchment

Sophie Rabitsch, Christa Hofmann, Junko Sonderegger 277 The parchment should not be pressed, but larger movements of the material should still be avoided. Furthermore, the surface of the folios should be accessible, without visual distor- tion. Future scientific research should be possible, therefore the storage solution should be reversible, in case other alternatives or solutions prove to be better in the future. Monitor- ing of fragile areas should take place once a year. Different storage models were considered during intensive discussions with several col- leagues: - A common solution for single parchment folios is the mounting in a window mat, using Japanese tissue strips adhered on all the margins. In the case of the folios of the Vienna Genesis, a double sided window mat that can be closed would be necessary. This version was considered too risky, due to the fragility of the parchment, especially the corroded areas. Furthermore, an adhesive would have to be applied to the edges of the folios in order to attach the Japanese tissue strips, which could introduce tension or moisture in the parchment. - Another possibility for storage is the sink mat, developed by Junko Sonderegger: single folios are placed in a smooth folder made of Japanese tissue paper, which is stored in a museum matboard folder adjusted with small spacers to avoid pressure applied to the parchment. The matboard folder is further protected in a larger sink mat with a cover board. This solution is minimally invasive, without the introduction of an adhesive, and the folios can be accessed on both sides. - Pockets of Japanese tissue or silk gauze were considered, such as for some folios of the Archimedes Palimpsest56. A model involving silk or synthetic gauze in combination with a closable double sided window mat was developed by Abigail Quandt. The single folios would be fixed between two matboard frames adjusted with two layers of gauze in the middle without the introduction of an adhesive. The two matboard frames are fixed together with small magnets. This model is minimally invasive, but even with the very thin gauze, the impression of the folios is changed. - Another model for storage was developed by Valerio Capra and Diego Rivella57. The single folios would be stored floating inside an acrylic box, adjusted with springs. Strips of Japanese paper would have to be applied to the margins of the folios. The tension could be adjusted, depending on the movement of the parchment. Like the first option, this version was considered too risky, due to the fragility of the folios. The models and different solutions were discussed at the expert meeting in November 2017. Valerio Capra kindly provided a full model of the frame-box. Colleagues at the Institute of Conservation at the Austrian National Library and the Conservation Department of the Al- 56 Quandt, 2011, pp. 156–161. 57 Valerio Capra presented the model at the expert meeting in November 2017. Open-Access-Publikation im Sinne der CC-Lizenz BY 4.0