|This dye was well known in ancient times, and although descriptions are vague, it is usually thought that Roccella tinctoria was the main lichen used. The term was first used in England in the 14th century.||In Europe various names have been used ...
|Here is a recipe for orchil: This description is by Roseto (1540) quoted
by Hellot (1750) and from Kok.
"Take one pound of the Orselle of the Levant, very clean ; moisten it with a little urine add to this sal-ammoniac, sal-gemmae ("sel terrestre et fossile", des Bruslons, p. 184), and saltpetre, of each two ounces ; pound them well, mix them together, and let them remain so during twelve days, stirring them twice a day; and then to keep the herb constantly moist, add a little urine, and in this situation let it remain eight days longer, continuing to stir it; you afterwards add a pound and a half of pot-ash well pounded, and a pint and a half of stale urine. Let it remain still eight days longer, stirring it as usual after which you add the same quantity of urine, and at the expiration of five or six days, two drachms of arsenic ; it will then he fit for use".
The first steps in understanding the origin of the purple colour were
taken by Pierre Robiquet (born
in Rennes 1780, died 1840) in1829 when he isolated
orcine as large
colourless prisms, from the lichen by extraction with ethanol. The purple
dye obtained from orcine, now called orcinol, by reaction with ammonia
and air he called orcéine.
For more recent chemistry, have a look at the orcein page.
|This is a drawing of Roccella tinctoria
from Dillenius's Historia Muscorum (1742)
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