Seite - 175 - in The Vienna Genesis - Material analysis and conservation of a Late Antique illuminated manuscript on purple parchment

Sophie Rabitsch, Antonia Malissa, Katharina Uhlir, Martina Griesser, Christa Hofmann 175 Sample preparation on parchment The chosen reference silver inks were applied on the flesh side of the parchment sam- ples. The parchment has been dyed with orchil made of Rocchella tinctoria, see chapter on purple dyeing of parchment. Greek letters were written with bamboo pens on pieces of purple parchment of sample sizes 2.5 x 2.5 cm and 3 x 3 cm in sub study 1. In sub study 2 the samples measured 5 x 4 cm. At the time the study took place, only a limited amount of parchment was available, especially parchment that was produced based on Late Antique techniques, see chapter on the parchment of the Vienna Genesis. Therefore, three different types of parchment were used. For sub study 1 each sample-set was produced twice, using two different types of lamb parchment: 1. modern lamb parchment from the company Anton Glaser (NP, new parchment)44 with an average thickness of 219 µm 2. lamb parchment produced in Late Antique style by Jiří Vnouček (LP, Late Antique parchment 1) with an average thickness of 104 µm, see chapter on the parchment of the Vienna Genesis The samples of sub study 2 were all prepared on lamb parchment produced by David Frank according to medieval methods (MP, medieval parchment)45. Frank’s parchment is very smooth on flesh and hair side, with an average thickness of 190 µm. The average thickness of the parchment folios of the Vienna Genesis measures 100–160 µm. For sub study 1, one half of the parchment was burnished with an agate polishing stone prior to the application of the silver inks. The influence of this finishing step on parchment and inks was intended to be evaluated after ageing. For sub study 2, the entire parchment was burnished in advance. Each reference sample-set of both runs was produced in quad- ruplicate and marked with the labels A–D (Fig. 23): A: unaltered as reference sample B: artificially aged C: sprayed with water in sub study 1; sprayed with a 3.5 % solution of sodium chloride (NaCl) in sub study 2; aged. D: sprayed with parchment glue containing acetic acid46, according to Wächter47; aged. 44 The exact methods and substances used in the production of the parchment are unknown. 45 The surface of the parchment was scraped and not split, as it was presumably done in Late Anti- quity; see chapter on the parchment of the Vienna Genesis. 46 Therefore, 60 ml of a 20 % parchment glue were prepared and mixed with 20 ml ethanol and 20 ml 5 % wine vinegar. 47 Wächter, 1982, p. 164. Open-Access-Publikation im Sinne der CC-Lizenz BY 4.0