Medieval painters built up a tremendous range of technical resources for obtaining brilliance and permanence. …
... "the dragon wraps his tail around the legs of the elephant, and the elephant lets himself sink upon the dragon, and the blood of the dragon turns the ground red; and all the ground that the blood touches becomes cinnabar, and Avicenna calls this dragonsblood." I am sometimes not at all sure that we do not pay too dearly for our scientific knowledge.
— The Materials and Techniques of Medieval Painting by Daniel V. Thompson (Page 125)