orchilla

Orchilla, also spelled orchilla or archil, is a purple dye obtained from certain lichens, most notably Rocella tinctoria. It has long been used to dye textiles such as wool and silk, especially in Europe and the Mediterranean, before the development of synthetic dyes.

Source and production: The dye is derived from the color compounds in the lichen thalli. Lichens used for orchilla grow on rocky coastlines and arid regions, with notable populations historically found around the Canary Islands, parts of North Africa, and the Mediterranean. Harvested lichens are processed to extract color and then fixed to fibers using metallic mordants, commonly alum. The resulting shade ranges from purple to reddish-purple, and can be darkened or altered with different mordants, such as tin or iron.

History and trade: Orchilla was a valuable natural dye from antiquity through the early modern period. The Canary Islands were a major source, and European trade networks moved the dye across the continent. Because the lichen grows slowly and yields are limited, orchilla was relatively expensive and often used for special textiles or as part of multi-dye recipes to achieve desired purples or browns.

Contemporary status: Today, orchilla is largely of historical or artisanal interest. It is used by natural-dye practitioners and in museum work to reproduce period textiles, and it remains a reference example of pre-synthetic dyeing practices.