Seite - 271 - in The Vienna Genesis - Material analysis and conservation of a Late Antique illuminated manuscript on purple parchment

Sophie Rabitsch, Christa Hofmann, Junko Sonderegger 271 parchment of the Vienna Genesis. The reactivation of Klucel G 5 % worked best with a small proportion of water added (ethanol-water 3:1 v/v). 37 ml of the described mixture are enough to work with Klucel G coated tissues for about an hour. When the reactivation did decrease, 10 ml of the ethanol-water mixture were poured onto the kitchen sponge cloth. In discussions, Andrea Pataki expressed concerns towards the mixtures of proteinous adhesives with the cellulose ether Klucel G, as this topic is not sufficiently investigated. Following those concerns, Luise Raab’s bachelor thesis49 for the Stuttgart State Academy of Art and Design dealt with the evaluation of mixtures of Klucel G and isinglass. The results of Raab’s thesis revealed that the two adhesives can be mixed, as long as Klucel G is dissolved in water. Alcohols cause denaturation of the protein, which has some effects on the swelling capacity and the adhesion of isinglass containing adhesive layers. A mixture of isinglass and Klucel G does not result in the combination of the qualities of those two components. Adhesive layers consisting of those two adhesives tend to swell more in etha- nol than the single components, but do adhere less. It does not seem that a mixture has ad- vantages and it is unclear if the aged mixture of Klucel G and isinglass results in changes of the solubility. It seems more suitable to use each adhesive on its own and not as a mixture. Table 6: Listing of the adhesives, their reactivation and the results; tested on folio 4, page 7 of the Vienna Genesis. Adhesive Reactivation Pros Cons 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, barely visible, better adhesion than on modern parchment Ethanol-water 3:1 v/v See above Ethanol Adhesion is not sufficient, easy to remove Due to the tests on the purple manuscripts and the results of Raab’s thesis, we decided to use Klucel G 5 % dissolved in water to prepare the remoistenable tissues. When prepared with water, the adhesive is easier to apply. The bonding is strong enough to stabilise tears and fragile areas of ink. The coated paper is visually unobtrusive. It forms an even layer and has a matt and smooth surface. For reactivation, 37 ml of a 3:1 v/v mixture of ethanol 49 Raab, 2017. Open-Access-Publikation im Sinne der CC-Lizenz BY 4.0