Seite - 190 - in The Vienna Genesis - Material analysis and conservation of a Late Antique illuminated manuscript on purple parchment

190 Alteration study of silver inks on parchment by three-fold measurements, respectively63 and averaged. By averaging these mean values, the average values shown in tables 3–5 were received. As can be seen in Table 3, the most significant decrease of the shrinkage temperatures for all three types of reference parch- ments takes place within the first five/six days. In the case of the parchment type NP the shrinkage temperature drops from 51.8 ± 0.8 °C down to 39.9 ± 0.5 °C. Compared to that, the main shrinkage temperatures TS of the reference parchments LP and MP decrease to 44.1 ± 0.8 °C and 46.4 ± 0.4 °C, respectively, originating from higher values of 61.8 ± 1.2 °C (LP) and 62.5 ± 1.4 °C (MP) for the unaged samples. A lower decrease of TS within the second half of the artificial ageing could be observed for all types of reference parchments: After 13 days TS of reference parchment NP was 33.3 ± 0.6 °C, while reference parchment LP showed a TS of 34.9 ± 0.7 °C and reference parchment MP had a TS of 40.7 ± 1.1 °C. With regard to the samples of the parchment type MP, which were treated with acidic parchment glue, TS decreased to 46.3 ± 1.6 °C after six days and 41.4 ± 1.1 °C after 13 days originating from TS of 64.3 ±2.6 °C. Table 3: 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 the reference samples prior to, after five days and after 13 days of artificially ageing. sample Tfirst [°C] TS [°C] TS, end [°C] ΔT [°C] Tlast [°C] ΔTcomplete [°C] NP_p_0d 48,7 ± 2,3 51,8 ± 0,8 54,9 ± 0,5 3,1 56,4 ± 0,8 7,7 NP_p_5d 36,5 ± 1,2 39,9 ± 0,5 42,8 ± 0,5 2,9 47,0 ± 1,3 10,5 NP_p_13d 30,2 ± 0,6 33,3 ± 0,6 36,3 ± 0,7 3,0 41,3 ± 1,6 11,1 LP_p_0d 58,7 ± 1,9 61,8 ± 1,2 65,1 ± 0,5 3,3 67,7 ± 0,6 9,0 LP_p_5d 41,0 ± 1,5 44,1 ± 0,8 47,4 ± 0,5 3,3 52,1 ± 2,2 11,1 LP_p_13d 31,4 ± 0,9 34,9 ± 0,7 39,8 ± 0,9 4,9 44,2 ± 0,9 12,8 MPB_p_0d 57,7 ± 2,2 62,5 ± 1,4 67,4 ± 1,8 4,9 71,0 ± 1,0 13,3 MPB_p_6d 43,9 ± 1,5 46,6 ± 0,4 49,6 ± 0,6 3,0 57,4 ± 2,7 13,5 MPB_p_13d 37,6 ± 1,0 40,7 ± 1,1 43,6 ± 0,8 2,9 52,0 ± 1,1 14,4 MPD_p_0d 60,2 ± 2,8 64,3 ± 2,6 67,4 ± 2,6 3,1 69,8 ± 2,0 9,6 MPD_p_6d 43,5 ± 2,0 46,3 ± 1,6 50,2 ± 1,1 3,9 55,1 ± 2,5 11,6 MPD_p_13d 36,2 ± 0,7 41,4 ± 1,1 45,6 ± 0,7 4,2 50,3 ± 0,9 14,1 63 More detailed results of each reference samples are given in the appendix in table 4 and Malissa, 2017, pp. 89–96. Open-Access-Publikation im Sinne der CC-Lizenz BY 4.0