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76 Purple dyeing of parchment
Orchil
This light-sensitive dye51 can be extracted from different types of lichen. Orchil (French
Orseille52) consists of various dye components whose chemical structures were first dis-
cussed by Hans Musso in the 1950s53. Historical recipes, dating from Antiquity to the 19th
century, mostly refer to the use of orchil on textiles. The colour can range from bluish-red,
brownish-red to intense purple54. The freshly dyed colour has vibrant hues. Orchil dyes
protein fibres like wool, silk, or parchment and does not work well on cellulose fibres55. A
mordant is not required56, but can be added.
Lichens are organisms consisting of a fungus and a photosynthetic partner, mostly
green algae or less often cyanobacteria, growing in a symbiotic association. The fungus
provides the physical protection of its cortex and the chemical protection of various prod-
ucts like colorants or precursors of those, while the photosynthetic partner provides carbo-
hydrate and energy for the metabolic process. The fungus is the source of the colorant
substances57. Lichens grow on solid surfaces like rocks or trees, in various environments.
Orchil can be produced from different types of lichens, which can vary a lot in their ap-
pearance.
Orchil dyes were produced from sea and land sources:
- A great variety of fruticose lichens, such as the Roccella spp. can be used to make or-
chil. Roccellae grow on coasts, often in subtropical or tropical regions58. Written sources
indicate that different species of Roccella were used in orchil making and these include
Roccella tinctoria, R. canariensis, R. fuciformis and R. phycopsis. These lichens differ in
growth and chemical composition and are often difficult to identify with the naked
eye59.
- A large group of crustose lichens grow on the siliceous rocks of European mountains60:
These include Lasallia pustulata, Ochrolechia tartarea, O. parella, and Pertusaria dealbe-
scens61.
51 Hofenk de Graaff, 2004, p. 278.
52 Cardon, 2007, p. 490.
53 Whitworth and Koren, 2016, p. 6.
54 Schweppe, 1993, p. 25.
55 Whitworth and Koren, 2016, p. 7; Beecken et al., 2003.
56 Schweppe, 1993, p. 25.
57 Cardon, 2007, pp. 485–486.
58 Cardon, 2007, p. 487.
59 Cardon, 2007, pp. 495–505.
60 Cardon, 2007, p. 487.
61 Cardon, 2007, pp. 506–513.
Open-Access-Publikation im Sinne der CC-Lizenz BY 4.0
The Vienna Genesis
Material analysis and conservation of a Late Antique illuminated manuscript on purple parchment
- Title
- The Vienna Genesis
- Subtitle
- Material analysis and conservation of a Late Antique illuminated manuscript on purple parchment
- Editor
- Christa Hofmann
- Publisher
- Böhlau Verlag
- Location
- Wien
- Date
- 2020
- Language
- English
- License
- CC BY 4.0
- ISBN
- 978-3-205-21058-0
- Size
- 17.3 x 24.5 cm
- Pages
- 348