Page - 267 - in The Vienna Genesis - Material analysis and conservation of a Late Antique illuminated manuscript on purple parchment

Sophie Rabitsch, Christa Hofmann, Junko Sonderegger 267 In order to reduce gloss on the surface of the coating, a 5 mm-thick silicone mould made of the surface of frosted glass was used as support33. The adhesives were applied in a single layer with a broad synthetic brush (da Vinci) in a flat angle on the matt silicone surface. Berlin Tissue, which is especially thin and difficult to coat, was placed into an ad- hesive layer which had been brushed on the silicon support in advance. The coated tissues were left to air dry slowly. A reactivation system developed by Eliza Jacobi was used34: A kitchen sponge cloth (Wettex) was cut to 10 x 10 cm and soaked with 37 ml of water or solvent mixture and placed on a water-resistent support. Two pieces of blotting paper of the same size (Canson, 250 g/m2) were placed on top and slightly pressed on, until the blotting paper was thor- oughly wetted (Fig. 27). The remoistenable tissue was cut to the size needed with a scalpel, placed on the blotting paper with the adhesive layer face down and smoothed on using a finger or a soft brush. After a few seconds it was then picked up with a pair of tweezers, air-dried for a maximum of 10 seconds and placed on the object, where it was dabbed on with a pattern brush (Japanese Surokami-bake); a piece of polyester web can be placed between the brush and surface. A piece of blotting paper and a small weight (lead snake, GMW) were then put on top. Not much pressure should be applied, as this can possibly lead to metal ion migration35. Depending on the Japanese tissue, the fibre direction must be taken into account when cutting the pieces. Berlin Tissue was cut following the fibre direction, so it did not tear when wet. For the tests, mixtures of ethanol and water 1:1 or 3:1 v/v and ethanol alone were used. Different support materials were chosen for the application of samples for the adhesive tests: Whatman paper No. 1, sheep parchment (Anton Glaser; slightly yellow, thickness of approx. 0.35 mm), and lamb parchment (Anton Glaser; white, thickness of approx. 0.19 mm). RK0 and KR4C were used to produce remoistenable tissues. The application and reactivation of the adhesives were carried out as described above. After the first evalu- ation, the adhesives that seemed to be the most suitable were tested on the fragmentary purple manuscript Cod. Ser. n. 280436 and on the margin of folio 7 of the Vienna Genesis. RKO and KR4C were coated with the different adhesives and adhesive mixtures de- scribed above. For the mixtures with proteinous adhesives, Klucel G was prepared with 33 Hofmann et al., 2015, pp. 166–168; since the publication the mould is made from the surface of frosted glass. 34 Neevel and Reißland, 2005; Jacobi et al., 2011, Van Velzen and Jacobi, 2011, Hofmann et al., 2015. 35 Hofmann et al., 2015, pp. 168 and 171. 36 The fragment is a piece of purple parchment (30 x 10.4 cm) with losses in the place of the former text. The parchment is dated to the 6th century and shows the qualities of Late Antique parchment. Open-Access-Publikation im Sinne der CC-Lizenz BY 4.0