In this series, we explore the stories behind certain pigments - natural and synthetic - and how these hues, and artists’ understanding of color in general has impacted the development of art. Read the first installment, What is Color? here.

What does green mean?

The human eye can detect more shades of green than any other color, which no doubt came in handy when our distant ancestors were attempting to navigate their way through a jungle, or discern whether a piece of fruit was ripe and ready to eat. However, as with all colors, the significance of green exists beyond the merely practical. Symbolically, the color has always been used to represent Nature itself, alongside notions of vitality, harmony and rebirth. Of course, green has also come to signify the modern environmental movement. But it’s not all positive - green can denote greed, envy and feeling rather worse for wear. Even the Devil himself was regularly to be found dressed in green attire throughout medieval literature and folklore. This ominous association was perhaps all too appropriate - after all, some greens can be deadly.

Early green pigments

Despite green being the most common color in the natural world, for most of human history, the range of green pigments available for the artist’s palette was remarkably limited. Before the Industrial Revolution, there was really only one source of green paint - copper. Malachite green (copper carbonate) had been used since ancient times, as had verdigris (copper acetate). The Roman author Pliny describes the actual process of making verdigris, in which copper plates were corroded over barrels of vinegar (acetic acid). Sadly, neither of these two greens were ideal. Malachite was stable but its tinting strength was very weak. Verdigris, in contrast, was a more vibrant green, but highly prone to blackening. Over the centuries, artists attempted to solve this impermanence problem in different ways. During the Middle Ages, they dissolved verdigris in pine balsam. Later, the Old Masters would take the precaution of isolating it between layers of varnish. But, despite these efforts, the lack of a brilliant and permanent green remained.

Scheele’s green

After millennia of artists being stuck with just two greens, thanks to the work of German-Swedish chemist Carl Wilhelm Scheele during the mid-1770s, there was finally a brash new kid on the block. The fact that Scheele’s green (copper arsenite) was an ‘arsenical’ green gives a clue as to what set it apart from the older greens. Put simply, he created it by combining copper and arsenic, which (as anyone who has read Agatha Christie will know) is a poison. Why would people risk using such a toxic substance? For one thing, it was hard to ignore. Scheele’s pigment was the most vivid green that had ever been made. But there was still a problem (aside from the deadly poison). Like verdigris, it was prone to fading and blackening, especially when it came into contact with lead and sulphur. Thankfully, this was exactly the kind of problem that scientists and entrepreneurs during the Industrial Revolution loved to tackle.

Emerald green

In 1814, two chemists in Bavaria produced an ‘improved’ version of Scheele’s green called emerald green. Somewhat confusingly, it also came to be known by many other names, including Paris green, Vienna green, Veronese green and Schweinfurt green (after its Bavarian city of origin). Technically-speaking, it was copper aceto-arsenite. It had greater covering power, more durability and an even more brilliant hue than Scheele’s original. Unfortunately, emerald green still displayed a tendency to blacken. It was also just as poisonous as its predecessor. Yet, despite these drawbacks, its sheer dazzling vibrancy meant that it quickly replaced the older copper greens on artists’s palettes across Europe. As far as green was concerned, nineteenth century painters had an exciting new toy to play with.

Emerald green in art

J.M.W. Turner used Scheele’s green in his early works, but by the 1830s he had switched to emerald green. The latter was also perfect for the Pre-Raphaelites, who wished to emulate the bright fresh colors of the Early Renaissance through the application of pure pigment over a brilliant white ground. For example, William Holman Hunt used emerald green to paint Porphyro’s rather arresting hat in The Flight of Madeline and Porphyro (1848) . Along with various new yellows and purples, John Everett Millais experimented with emerald green to evoke an almost hallucinatory intensity in his depictions of nature. Critics accustomed to the soupy brown style of older landscape paintings infamously decried Millais’s vivid efforts as ‘vulgar’.

As late as 1862, Manet used both Scheele’s green and emerald green in Music in the Tuileries. The last ever recorded use of Scheele’s green in a painting occurred a few years later. However, emerald green continued to be used until the end of the century by Impressionists such as Monet and Pissarro, along with Post-Impressionists like Cézanne, Gauguin and van Gogh.

Green for Danger!

Even though Scheele understood how poisonous arsenical green could be, the possibility of vast financial reward evidently outweighed any pressing urge to inform the public. As a consequence, for several decades, there was widespread ignorance about the danger. The relative cheapness of manufacturing both Scheele’s and emerald green meant that the brilliant new color was used for household paint, wallpaper, clothes, toys, medicines and even food dye in sweets.

The sheer variety of romantic sounding names for emerald green (‘Paris’, ‘Veronese’, ‘Imperial’) was partly an attempt to distract attention from how toxic the new pigment was. Sadly, the ubiquity of emerald green during nineteenth century led to terrible cases of vomiting, skin lesions, diarrhoea and even cancer. Stories of children ‘wasting away’ in green rooms were common, whilst women would find themselves fainting in green dresses.

By the 1830’s, the danger it posed had begun to be understood, but despite a ban in several countries, William Morris continued to use the green in his range of wallpapers into the 1880s.

Some have conjectured that its most famous victim was Napoleon Bonaparte. Whilst in exile on the island of St Helena, the defeated French general died (most likely) from stomach cancer. The fact that his hair samples showed high levels of arsenic has led many to suggest a causal connection. It seems entirely possible that his bright green bedroom walls had reacted with the humid climate to release toxic arsenic fumes.

Modern greens

Whilst emerald green opened up new artistic horizons for nineteenth century artists, other greens soon emerged - the best of which was viridian (chromium oxide dihydrate). Originally invented in 1838 in Paris and made to a closely guarded recipe, by 1859 viridian had been patented for mass-production by Guignet. Painters increasingly preferred this powerful, non-toxic and completely stable green (which, very confusingly, the French referred to as ‘vert émeraude’)

The 20th century witnessed many other new greens - perhaps the closest in colour to emerald green came from the group of synthetic pigments created in the 1930s known as phthalos (thankfully without any of the attendant hazards).

By the early 1900’s, emerald green had been banned for use as a pigment. Its days on the artist’s palette were well and truly up.

It was perhaps only fitting that, by the 1930s, it was being used as an insecticide. Scheele’s green had, at last, found its true purpose in life.