Seite - 174 - in The Vienna Genesis - Material analysis and conservation of a Late Antique illuminated manuscript on purple parchment

174 Alteration study of silver inks on parchment Reference ink ST14 Reference ink ST14 is another variation of reference ink ST4. It is based on the same recipe (MC CCXLVIII: variation II, 1, 2; model 130, 131)43 by Trost. In contrast to ST4 and ST13 the silver chips used for the preparation of silver powder were ground adding water as grinding aid instead of wine vinegar. 102.3 mg of silver chips were ground in a marble mortar together with 10 drops of water for 20 minutes. The obtained silver powder was washed six times, dried and mixed with 0.098 g of potassium nitrate (KNO3). 20 drops of isinglass (5 %) were added. The refer- ence ink showed the same problems regarding its further use as ST13. It seemed to be a bit translucent and had a brownish colour (Fig. 22). 43 Trost, 1991, p. 236. Fig. 21: Sample ST13_A, as described in fig. 18. Fig. 21: Sample ST13_A, as de- scribed in fig. 18. Fig. 22: Sample ST14_A, as described in fig. 18. Open-Access-Publikation im Sinne der CC-Lizenz BY 4.0