Emerald Green

Summary: Emerald Green and its chemical relation, Scheele’s Green are derivatives of copper and arsenic.  They are unavailable today due to their toxicity as well as their reactive nature with any sulfur-containing pigment. The green hue has a relationship with two important characters in 18th-century history.

Long ago, on a trip to New York City, I was curious to see what a quality piece of jewelry containing an emerald looked like. Knowing that I would not be fooled by an imitation, I walked into Tiffany’s on 5th Avenue and found the case containing emerald rings. I was disappointed because the emerald rings on display were somewhat cloudy green, lacking the clarity and sparkle that I was expecting.  I was anticipating seeing a green colored translucent stone. It seems I was confusing emeralds with tourmalines.

Images of Napoleon Bonaparte, George Washington and an emerald gemstone

I came into contact again with the term Emerald Green as a pigment, not as a gemstone, when organizing antique paint boxes in the Art Materials Collection and Research Center during my career at the National Gallery of Art in Washington, DC. Half-pans of true Emerald Green were in several of the 19th-century paint boxes, and their hue reminded me of the visit I made to Tiffany’s many years prior.

Like many other pigments, synthetically derived Emerald Green was created in a laboratory in 1814 during the period when chemists were busy inventing many new materials. But knowing Emerald Green’s sinister associations made it an interesting curiosity regarding how casual it was to have it included in an artist’s paintbox along with several other dangerous pigments.

We have taken all of the “perilous excitement” out of pigments.  Many of them used to be extremely dangerous.  Artists lived on the cutting edge of having the materials they used be a potential source of their demise.  What pigment today can you name that could be both a colorant and a rat poison simultaneously? (See below)

Currently, despite what many artists say, the modern pigments we use are fairly safe to handle. Seriously, some artists claim that the mere presence of cadmium paint in their studio has the potential to harm them.  I view many comments from concerned artists who fear that they are slowly being poisoned by the cadmiums or cobalt pigments they use for their paintings.  However, when reviewing how they use them and assessing their studio safety habits, it would be a baffling mystery if they ended up being hurt by their pigments. 

Most artists do not come into bodily contact with pigments that would cross the blood barrier, digestive tract, or pulmonary system.  Most artist keep paint on their brushes.  They tend not to slather themselves with pigments, especially when having open cuts on their skin, partake in intentionally eating or accidentally ingesting paints, or sand paint layers so that the dust produced flies up and is inhaled.  Somehow, despite some very loose casual practices in some art schools, most painters are fairly careful when it comes to contact with pigments. 

A few pigments have been noted more for their toxicity than their color characteristics.  Emerald Green is a fairly unnatural, high chroma, bright green that one would be hard pressed to think would become so popular during its relatively short lifespan.  However, it does make for an interesting story.

Emerald Green is a combination of acetic acid, copper, white arsenic, and sodium carbonate. It was introduced in 1814.  Mixed in a hot solution, the precipitate yielded from the combination of chemicals is washed and dried to obtain the finished pigment.  It will react when exposed to a sulfurous atmosphere and/or sulfur-based pigments.  It was far more popular with decorators than with fine artists.  The pigment was used in wallpaper and house paint.  Emerald Green also served to provide substantial protection against pest infestation because the same combination of copper arsenic material was also marketed as a pesticide. 

It was even rumored to play an important role in Emperor Napoleon’s undoing.  Reportedly fond of the color, the emperor had his exile home in St. Helena decorated with wallpaper containing Emerald Green.  Folklore states that Napoleon’s premature death may have been caused by the noxious fumes coming from the bright green wallpaper.   This claim has been disputed, and an autopsy indicated that while arsenic was present in Napoleon’s body, it was ingested at intervals far prior to the commercial introduction of Emerald Green.  Analysis of his nails and hair, which form a strong timeline of past contact with material in the environment, played an important part in determining that the period of incarceration near the end of his life was not part of a sinister plot to cleverly poison him slowly.  This story has many fascinating twists and turns.

Another famous leader seems to have favored a chemical relative of the yet-to-be-invented Emerald Green.  The interior of the dining room at George Washington’s plantation home, Mt. Vernon, in Virginia, is painted a bright, mint green hue.  It is a mixture of an intense green color with white.  As with many colonial homes, it is a striking contrast to the warm, earthy colors found in most eighteenth-century residences.  We tend to think of our colonial ancestors as a bland and colorless lot who would tremble or sigh with delight at the sight of yellow ochre.  Washington’s dining room goes far beyond common earth colors.  It reminds us that chemical technology had a place in the lives of those who could afford to have it.  The construction of Washington’s dining room started in 1774, and it was completed in 1788.  Washington was said to have harbored a keen interest in following the latest European trends of his day, and it stands to reason that he would have chosen Emerald Green’s close “cousin,” Scheele’s Green, invented in 1778. Washington had the walls of his dining room painted with it.  It is an arsenite of copper that closely resembles Emerald Green in color and chemical composition.  So, for all practical purposes, it imitates Emerald Green in hue and intensity.

Napoleon and Washington did have overlapping life dates.  They both fancied intense green and liked to be nattily attired.  For me, I would prefer eating a Napoleon (the puff pastry cream and fondant icing dessert) while sitting in Washington’s high-ceiling dining room at Mount Vernon, VA.  The room is elegant.  The views out of the windows of the room are spectacular.  The problem would be the pesky tourist interrupting me with questions while I savored each bite of that heavenly dessert.  At least the dining room would be rat-free!

Syntax of Color

 Adapted from Grammar of Color article, Vol. 3 No. 7 in 2007.

Keywords: Emerald Green, Scheele's Green, arsenite of copper, poisonous, Mt. Vernon, George Washington, Napoleon Bonaparte,pigments, artists' materials, 19th-century, antique paint boxes, 1814, 1788.