Orseille
The Orseille is a purple dye selected from lichen species of the genus Roccella is obtained that grow close to the coast. In ancient times it was considered to be the most valuable dye alongside the purple of the purple snail . Theophrastus already describes the color effect. In the fourth century AD the use of the dye decreased, possibly the slow-growing lichens were decimated too much.
For production, shredded lichens were mixed with diluted ammonia or urine and then fermented for a few days to months, which resulted in the red dye orcein . The by-product obtained with the addition of potassium carbonate , lime and glue was the deep blue litmus .
literature
- Heribert Schöller (Ed.): Braiding. History, biology, systematics, ecology, nature conservation and cultural significance . Kramer, Frankfurt am Main 1997, ISBN 3-7829-1151-2 , p. 192 ff . ( Kleine Senckenberg row 27).