In England, very little is known of the painting trade prior to the 13th century. It was at this point when ‘guilds’ began to form (an association of artisans or merchants who controlled the practice of their craft in a particular town) and amongst them were the Painters Company and the Stainers Company. With the consent of the Lord Mayor of the City of London in 1502, the two guilds merged and became The Worshipful Company of Painter-Stainers. The guild regulated the quality of the craft and acted as protector of the trades secrets. In 1606 Parliament granted a bill to enforce protection from outside competition such as plasterers. The Act legislated for a seven year apprenticeship and barred plasterers from painting. The enforcement of this Act was sought by The Worshipful Company until the 19th century.

A figure-eight shaped curve whose equation in polar coordinates is ρ²=a² cos 2θ

In algebraic geometry a lemniscate may refer to any of several figure eight shaped curves. The word comes from the Latin “lēmniscātus” meaning “decorated with ribbons.”

In lazure painting it is the ‘brushing out’ technique of the translucent glazes.

One day in around 1704, a Herr Diesbach was settling down to make carmine lake according to a tried and tested recipe – mixing ground up cochineal, alum and ferrous sulphate, then precipitating it all with an alkali – when he realised he had run out of alkali. He borrowed some from his boss, but did not realise it had been distilled with animal oil. Suddenly, to his amazement, he found blue instead of red in his flask. The clue is in the ‘animal’ element: the mixture had contained blood, which contains iron. Diesbach had unwittingly created iron ferrocyanide, which was dubbed ‘Prussian blue’ and was instantly popular, particularly as a house paint.

From Travels through the Paintbox by Victoria Finlay.