Seite - 269 - in The Vienna Genesis - Material analysis and conservation of a Late Antique illuminated manuscript on purple parchment

Sophie Rabitsch, Christa Hofmann, Junko Sonderegger 269 Gelatine-Klucel G 5 %, isinglass-Klucel G 5 %, rice starch paste, rice starch paste-Klucel G and wheat starch paste-Klucel G showed the best results regarding adhesion and optical features like matt and smooth surfaces. Depending on the surface of the support, Klucel G 5 % (in water) is suitable as well. When isinglass is mixed with Klucel G, it forms better films, as the viscosity is higher. Klucel G prepared with water can be brushed on a Japanese tissue more evenly than when being prepared with ethanol, so it was decided to only use Klucel G prepared with water for further tests. Rice and wheat starch and their mixtures resulted in cockling of the parchment on some samples. As no stress should be introduced to the fragile parchment, these adhesives were excluded from the screening. After the ac- celerated ageing, all proteinous adhesives and their mixtures yellowed at least a bit, with parchment glue changing the most. The first tests showed that the Japanese tissues KR4C and Berlin Tissue are more suit- able for the mending than RK0. The rougher the surface that has to be mended, the better the bonding of most of the adhesives. The majority of the adhesives showed better ad- hesion on Whatman paper and on the rougher side of the parchments. The material that has to be stabilised has a great influence on the bonding. Therefore, a smaller choice of adhesives was tested on the fragment of the purple manuscript Cod. Ser. n. 2804 and on folio 7 of the Vienna Genesis. A selection of adhesives and adhesive mixtures were applied on KR4C. Thin strips of tissues were activated and applied on the fragment of Cod. Ser. n. 2804. The adhesives, their reactivation and the results are listed in Table 5. The small strips of tissue were subse- quently mechanically removed. Table 5: Listing of the adhesives, their reactivation and the results; tested on Cod. Ser. n. 2804 Adhesive Reactivation Pros Cons Isinglass 5 % Ethanol-water 1:1 v/v Sufficient adhesion, but can be removed Fibrous surface, fibres re- main on the surface of the parchment when peeled off. Gelatine 5 % Ethanol-water 1:1 v/v Adhesion is not sufficient Gelatine 5 %-Klucel G 5 % (in water), 1:1 v/v Ethanol-water 1:1 v/v Adhesion is not sufficient Isinglass 5 %-Klucel G 5 % (in water), 1:1 v/v Ethanol-water 1:1 v/v Sufficient adhesion, closed surface, adheres better than Klucel G alone Klucel G 5 % (in water) Ethanol-water 1:1 v/v Sufficient adhesion, closed surface Open-Access-Publikation im Sinne der CC-Lizenz BY 4.0