Seite - 191 - 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 191 Table 4: Mean values for the temperatures of the first observed shrinkage activity (Tfirst), the shrinkage temperatures (TS), the temperature at the end of the main shrinkage interval (TS, end), the length of the main shrinkage interval (ΔT), the temperature of the last observed shrinkage activity (Tlast) and the length of the entire shrinkage interval (ΔTcomplete) of polished and unpolished reference samples of the first part of the ageing study after five days of artificial ageing. Sample Tfirst [°C] TS [°C] TS, end [°C] ΔT [°C] Tlast [°C] ΔTcomplete [°C] ST1B/NP/up/5d 37,8 ± 0,3 40,2 ± 0,8 43,4 ± 0,0 3,2 47,0 ± 0,9 9,2 ST1B/NP/p/5d 37,7 ± 0,6 39,2 ± 0,9 42,8 ± 1,2 3,6 47,1 ± 1,0 9,4 ST2B/NP/up/5d 37,9 ± 0,7 41,1 ± 0,5 43,7 ± 0,6 2,6 46,8 ± 0,4 8,9 ST2B/NP/p/5d 35,8 ± 0,7 40,5 ± 0,7 43,5 ± 3,0 3,0 46,6 ± 0,6 10,8 ST3B/NP/up/5d 37,2 ± 1,7 40,0 ± 0,9 42,5 ± 1,3 2,5 49,1 ± 2,0 11,9 ST3B/NP/p/5d 35,3 ± 0,7 40,0 ± 0,1 42,7 ± 0,5 2,7 53,7 ± 2,5 18,4 ST4B/NP/up/5d 35,6 ± 0,6 38,5 ± 1,1 42,9 ± 3,6 4,4 47,2 ± 2,1 11,6 ST4B/NP/p/5d 34,4 ± 1,6 39,2 ± 1,6 42,4 ± 0,5 3,2 49,8 ± 1,7 15,4 ST1B/LP/up/5d 41,9 ± 0,1 43,9 ± 0,1 47,3 ± 0,4 3,4 50,9 ± 1,8 9,0 ST1B/LP/p/5d 42,0 ± 0,6 44,0 ± 0,1 46,7 ± 0,2 2,7 49,0 ± 1,2 7,0 ST2B/LP/up/5d 43,1 ± 0,7 44,4 ± 0,4 46,9 ± 0,4 2,5 51,3 ± 1,8 8,2 ST2B/LP/p/5d 39,0 ± 0,3 42,5 ± 0,4 46,9 ± 0,6 4,4 51,2 ± 1,6 12,2 ST3B/LP/up/5d 42,8 ± 0,5 44,7 ± 0,2 47,9 ± 0,8 3,2 55,3 ± 3,6 12,5 ST3B/LP/p/5d 41,8 ± 0,4 44,2 ± 0,5 47,5 ± 0,3 3,3 56,1 ± 3,4 14,3 ST4B/LP/up/5d 43,7 ± 2,0 45,4 ± 1,4 47,2 ± 0,8 1,8 53,0 ± 1,3 9,7 ST4B/LP/p/5d 43,0 ± 1,7 44,9 ± 0,3 47,2 ± 0,6 2,3 52,0 ± 1,2 9,0 Along with the discussed decrease of the shrinkage temperatures of the artificially aged samples, a reduction of the possible five shrinkage intervals – A1, B1, C, B2 and A2 – could be observed. The reference samples, which were made of the parchment types NP and LP and aged during the first series of the ageing study, only showed three shrinkage intervals – A1, C and A2 – after 13 days of artificial ageing. In contrast, the reference samples, which were made of the parchment type MP and aged during the second part of the ageing study, still showed all five shrinkage intervals. As it was described above, one half of each reference sample was burnished with an agate polishing stone prior to the application of the silver inks in the course of sub study 1 with the purpose of checking if this mechanical preparation step had an impact on the condition of the parchment after ageing. As it can be seen in Table 4, the shrinkage tem- peratures of unburnished and burnished samples only vary between 38.5 °C and 41.1 °C for samples of the reference parchments NP and between 42.5 °C and 44.9 °C for samples of the reference parchments LP. Since these minor variations are in accordance with the Open-Access-Publikation im Sinne der CC-Lizenz BY 4.0