Chrome oxide green & Viridian

The two pigments are very closely related, as viridian is the hydrated, transparent form of chrome oxide green.

Chrome oxide green

Chromium was discovered in 1797 by the French chemist Louis Nicolas Vauquelin (1763-1829), while he was analysing Siberian red lead¹, or crocoite (lead chromate), as it is known today. Crocoite had already been used as a pigment since the 1770s.

The orange-red mineral had been discovered in the Ural Mountains in 1766 by the German mineralogist Johann Gottlob Lehmann (1719-1767). However, Lehmann died shortly afterwards, apparently as a result of an accident in his laboratory, before he had the opportunity to undertake a thorough analysis of the mineral².

Because of the many colourful compounds that Vauquelin observed could be produced from the element he had isolated from crocoite, the French chemist Antoine François de Fourcroy (1755-1809) and the French mineralogist René Just Haüy (1743–1822) suggested the name Chromium for the new metal³, derived from the Greek word χρώμα (chroma), meaning “colour”. Among Vauquelin’s investigations of chromium was chromium oxide, formed by calcining the starting materials in a furnace and therefore pyrogenetic in origin⁴. Around 1798-1799, he proposed chromium oxide as a pigment for artists, potentially improving their palettes. However, its high production cost prevented it from being widely adopted by artists.

It has been identified in J. M. W. Turner’s painting Somer Hill (1812), now in the National Galleries of Scotland in Edinburgh, making it one of the earliest — if not the earliest — documented occurrences of the pigment in a painting⁵.

Viridian

The hydrated form, viridian, was discovered several years later, around 1838, by the French colour maker Pannetier and his assistant Binet, according to Church⁶. They kept their manufacturing formula secret. If chrome oxide green was already extremely expensive because of its production cost, the viridian produced by Pannetier and Binet was reportedly more than 100 times as expensive⁷.

In 1859, the French chemist Charles Ernest Guignet (1829-1906) obtained a patent for producing viridian by a somewhat more affordable method⁸.

However, Sarah Herring of the National Gallery in London⁹ presents a different account:

“Arsenne refers to viridian in his ‘Manuel du Peintre et du Sculpteur’ of 1833, stating that it was available from the colourmen Colcomb-Bourgeois (note 25). He writes: ‘This last colour marries perfectly well with browns and gives the greens a very intense tone. When it is known it will be of great use to the landscapist’ (note 26). It has also been found in a painting from Corot’s second trip to Italy, View of Riva of 1835 (Munich, Neue Pinakothek), where it is mixed with cobalt blue, thus dulling it and making it more like opaque chromium green (note 27). It was extremely expensive at this time but price does not seem to have been a disincentive to Corot, as by 1821 he was in receipt of a yearly income of 1,500 pounds (note 28). Corot was already a customer at Colcomb-Bourgeois when he first went to Italy in 1825, and on 29 October 1826 wrote to his friend Abel Osmond for colours from the firm (note 29). Although Arsenne published this source in 1833, the evidence from this painting is that the colour was being made by Pannetier and available even in the 1820s from these colourmen.” [refer to the article for further sources].

“Viridian” derives from the Latin viridis, meaning “green” and “fresh”. The pigment was given this name after previously being known as vert Pannetier and vert Guignet, after its respective manufacturers.