The Herbarium (RNG) has been assisting me in drawing lichens for a Reading Science Week art Exhibition called ‘Symbiosis’. Recently I’ve been focusing on lichen species used in traditional dying. Below are some images including photos of me drawing taken by Reading’s Dr M! Ochrolechia and Roccella spp have been historically used in making ‘cudbear’ and ‘orchil’ purple dyes, by processing with ammonia to convert precursor lichen substances to orcein. Parmelia spp have also been used in making ‘crotal’, a yellowish to brown dye.
Its quite challenging to find modern reference sources for lichen dyes (and I’d be interested to hear from anyone with any experience), however, one that has proved useful to us on this project is ‘Lichen Dyes: The New Sourcebook’ by Karen Casselman and there is interesting historical information in ‘Vanishing Lichens: Their History, Biology and Importance’ by D.M. Richardson – one of my favourite lichen books, now out of print but its very easy to get a second hand copy cheaply via sites like AbeBooks or Amazon.