The knowledge of how to make vermilion from mercury and sulphur was rare until around the 12th century. For this reason, it was used sparingly in manuscript painting in the 11th, 12th and even 13th centuries, mostly being used for important headings and for so-called ‘red letter’ days. However, by the 15th century, the manufacture and use of vermilion was widespread. The painter Cennino Cennini noted that it was easier to buy it from the druggist than to waste time preparing it.
Hues that heal
Where vermilion was used to create a brilliant red, saffron was used in manuscript painting to produce a pure yellow, one with no hint of green. Persian painters often used a mix of saffron and verdigris to obtain a beautiful pistachio colour. Several Persian recipes from the 18th century suggest that this mix prevents the verdigris from damaging the paper. Did they know about its antioxidant properties even then?
Zoroastrian priests wrote special prayers in saffron ink to ward off pests and evil spirits, while medieval recipes suggest taking saffron to calm the nerves, as a sort of natural Prozac. Saffron was also used traditionally for asthma and coughs, to loosen phlegm, and to aid digestion.
Another pigment with medicinal properties is indigo, which has been used as a dye since at least 500 CE. The process of making it is long and complicated, and was a closely guarded secret. In medieval times, blue dyers were the elite of their profession: if you knew how to dye with it, you only dyed in that colour. In manuscript painting, indigo was often used because it was the cheapest of the three blues. The other two are mineral blues – azurite and lapis lazuli (ultramarine).