Page - 89 - in The Vienna Genesis - Material analysis and conservation of a Late Antique illuminated manuscript on purple parchment

Sophie Rabitsch, Inge Boesken Kanold, Christa Hofmann 89 colour can be directly used for painting, but not for dyeing, as it is water-insoluble101. In order to process and make it useable for dyeing, time consuming processes of reduction and oxidation have to take place102. The glands have to be fermented and the colorant has to be reduced in alkaline conditions in order to achieve its soluble form. The dye can then be absorbed by textiles or, in this case, parchment. In this state, the dyestuff is lime-green. When the dyed material is removed from the vat and exposed to the air, the contact with the oxygen reconverts the lime-green compounds into their purple water-insoluble form, which is then bound to the fibres103. Antique sources indicate that the origins of shellfish purple are located in the Near East, in the Phoenician empire104. The city Tyre was so famous for the production and trade of purple that the colour was named Tyrian purple105, a term still used today. The earli- est archaeological traces were found for example in Crete (Greece, 1,900–1,700 B. C.)106, Ugarit107 (Syria, 15th–13th century B. C.108) and Sarepta (Lebanon, around 1,350 B. C.)109. In Antiquity, the marine snails were mainly fished in the Mediterranean Sea110. There were different kinds of purple molluscs used by the ancient civilisations of the Mediterranean and the Middle East: Bolinus brandaris, Hexaplex trunculus and Stramonita haemastoma111. However, the use of molluscs is not unique to the Mediterranean world. Purple dyes were extracted from molluscs along the Atlantic coasts of Europe, in South and Central Amer- ica112 and in several ancient civilisations in Asia113. Caius Plinius Secundus, known as Pliny the Elder, described the production of the dye in his Natural History (Plin., HN IX, 38) 4: The vein already mentioned is then extracted and about a sextarius of salt added to each hundred pounds of material. It should be soaked for three days, for the fresher the extract, 101 Cardon, 2007, p. 4. 102 Quandt, 2018, p. 122. 103 Cardon, 2007, p. 4. 104 Bogensperger, 2015, pp. 158–159. 105 Schweppe, 1993, pp. 30–31. 106 Carannante, 2011, p. 11. 107 Schweppe, 1993, p. 31. 108 Barber, 1991, p. 229. 109 Quandt, 2018, p. 121. 110 Boesken Kanold, 2017, p. 67. 111 Cardon, 2007, pp. 566–586. 112 Several indigenous peoples in Central and South America dyed their textiles by rubbing the mucus of the living snails directly onto the yarn. The technique is still practiced today. Cardon, 2007, pp. 557–558. 113 Cardon, 2007, p. 553. For molluscs used in other parts of the world, see Cardon, 2007, pp. 586– 604. Open-Access-Publikation im Sinne der CC-Lizenz BY 4.0