Posts Tagged ‘Schweinfurt green’

Bottle with emerald green pigment

Once upon a time green paint literally killed people. In 1814 in Schweinfurt, Germany, two men named Russ and Sattler tried to improve on Scheele’s green, a paint made with copper arsenite. The result was a highly toxic pigment called emerald green. Made with arsenic and verdigris, the bright green color became an instant favorite with painters, cloth makers, wall paper designers, and dyers. The first commercial British arsenic was produced at Perran-ar-Worthal in 1812, and at Bissoe in the Carnon Valley in 1834. Their product appealed to the Lancashire cotton industry which used the chemical in pigments and dyes. It was also used by other industries such as glass manufacture (as a decolouriser), in the production of lead-shot, leather tanning, soaps, lampshades, wallpaper manufacture (to create green and yellow print), pharmaceuticals, agriculture for sheep dips, children’s toys, candles, a highly effective rat poison, etc.*

“Manufacture of [emerald green] began in 1814 at the Wilhelm Dye and White Lead Company of Schweinfurt. It was more popular than Scheele’s green and was soon being used for printing on paper and cloth; it even coloured confectionary. –  The Elements of Murder: A History of Poison, John Emsley

Textured Georgian wallpaper

Emerald green was also called Schweinfurt green, Paris green, and Vienna green. The toxicity of dye made with emerald green was not initially recognized, until the recipe was published in 1822, and
“…its poisonous nature was revealed. Manufacturers then changed the recipe, adding other ingredients to lighten the colour, and changing its name accordingly in an effort to disguise its true nature.” – Murder, Emsley
Eventually, the use of this pigment was abandoned when it became generally known that people who wore clothes dyed with the substance tended to die early. To this day the French avoid making green theater costumes.** Emerald green was also used to color confectionary and cake cake decorations:
“The leaves of artificial flowers in particular were coloured with various arsenic greens and they were very popular in Victorian households. The industry making them employed hundreds of young girls, who suffered accordingly from chronic arsenic poisoning…at a banquet held by the Irish Regiment in London in the 1850’s the table decorations were sugar leaves coloured by them. Many of the diners took these home for their children to eat as sweets and several deaths ensued. At another dinner in 1860 a chef was eager to produce a spectacular green blancmange and sent to a local supplier for green dye. He was given Scheele’s green and three of the diners later died.” – Ibid

Floral border wallpaper, Ipswich, late 18th c.***

Wallpaper made with Scheele’s green was deadly, By 1830, wallpaper production had risen to 1 million rolls a year in the UK, and by 30 million in 1870. Tests later revealed that four out of five wallpapers contained arsenic. Leopold Gmelin (1788-1853), a famous German chemist, suspected as early as 1815 that wallpaper could poison the atmosphere. He noticed that the substance gave off a mouse-like odor when the paper was slightly damp. Gmelin warned people to strip their rooms of the paper and advocated banning Scheele’s green, but he was too far ahead of his time.

In 1861, Dr W. Fraser tested wallpaper that contained arsenic.The threat, he said, came from breathing the dust of the papers, especially flocked wallpaper. The warnings went unheeded, and by 1871, arsenic production had increased to the point that Britain had become its largest producer and consumer. An addition of a small amount of arsenic, for example, would neutralize iron in glass and give it a green tint. “Potassium chromate (K2CrO4) is yellow and this colour can be imparted to certain glasses. To produce emerald green glass in which a yellowish cast has to be avoided the addition of tin oxide and arsenic is necessary.” (Substances used in the making of colored glass.)

Soon arsenic was exported for the making of pesticides in the United States. Health considerations did not end the use of arsenic-laced wallpaper. By the 1870’s synthetic green dyes began to replace arsenic, and fewer people were placed in danger by its poisonous gases. Experiments at the end of the 19th century proved that arsenic pigments in damp or rotting wallpaper were lethal. The mold that grew on damp wallpaper emitted a toxic odor that smelled of garlic.

The French painter Cezanne had an affinity for using paris green, and it might have been no coincidence that he suffered from severe diabetes. The pigment had a tendency to turn black when exposed to heat and thus it did not become universally popular with artists. Even with scientific evidence of its highly toxic nature, production of emerald green paint was not banned until the 1960’s.

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