“Facts and Inferences”—Digitizing Shadows from the Walls of Death Part 3

NLM has digitized and made publicly available for the first time, one of four known copies of Shadows from the Walls of Death: Facts and Inferences Prefacing a Book of Specimens of Arsenical Wall Papers, 1874. In this three-part series learn more about the origins of this rare book, the digitization effort, and the arsenic pigments of the 19th century.

By Kristi Wright ~

Robert Kedzie’s book, Shadows from the Walls of Death, was published amidst rising awareness of the dangers associated with arsenic-laden wallpapers.   Arsenic was a component in the production of popular eye-catching colors in multiple shades including green, purple, blue, yellow, grey, red, mauve, and brown. Though arsenic powder was known to be a potent poison, arsenical colors became quite fashionable.  Greens were especially trendy and ultimately their nearly ubiquitous, insidious, presence in 19th century domestic goods made them notorious.

Arsenical Green in 19th Century Wallpapers

Toxic pigments including lead, chromium, cadmium, mercury, and arsenic have longstanding spots in artists’ palettes.  Shades of historic greens include sap from buckthorn berries, natural earth pigments in a variety of shades, the powdered malachite mineral, and a corrosive copper-acetate called verdigris.  Mixing blues and yellows to create green was also common, and medieval painters and manuscript illuminators frequently used a shade of green known as vergaut that was a mix of orpiment, which is a yellow arsenic-based mineral, and indigo, a plant extract.  These greens, while beautiful, are often described as dull by comparison to later synthetic colors.

In the late 1770s when chemist Karl Scheele published his recently discovered recipe for a green color combining copper oxide, arsenic trioxide, and water to create copper arsenite, the use of arsenic in a pigment would not likely have alarmed anyone.  It was cheap to make and resulted in the most brilliant green obtainable at that time.  Demand for products colored with the alluring ‘Scheele’s green’ grew rapidly and soon it was produced in great quantities.  In the year 1860, 700 tons of the pigment were produced in England alone!  It was popular for coloring common household items including toys, candy wrappers, food coloring, artificial flowers, textiles, window coverings, lamp shades and, of course, wallpapers.

Another arsenical green, copper acetoarsenite, was developed around 1800 and it became widely available by 1814.  This color was marketed by many names including Paris green, Schweinfurt green, Mitis green, and Emerald green.  Kedzie describes it quite admirably in an introductory pamphlet to Shadows from the Walls of Death:

“There is not in commerce a green paint so beautiful and unfading as the aceto-arsenite of copper.  When mixed with other colors in toning it still gives a clear and fresh color.  The temptation for the paper printer to use it is very strong.  It is often used to give a delicacy to the shading where the unpracticed eye would fail to detect any shade of green.”

Both Scheele’s and Paris greens were used in 19th century wallpapers.  The brighter hues are eye-catching and when mixed with other colors they were often used as a subtle base layer, or ground, to tone the large areas of the wallpaper.  Thus, even papers that did not contain bright greens could still be thoroughly arsenic coated.  These papers were highly toxic with an average of 30 grains, or about 2 grams, of arsenic per square foot.

Manufacturers of arsenical colors, printers and papermakers using them, and consumers were all at risk of inorganic arsenic poisoning.  The health effects of regular exposure were known, and the Massachusetts State Board of Health recommended in the 1870s that paper printers working with arsenical colors limit work to two or three weeks at a time before rotating to a different project so that they could recover.  Exposure during just a few weeks could be significant.  One 1860s papermaker in England stated that two tons of arsenic were used weekly in his shop!

In the home, arsenic was theorized to become airborne as either a particulate or, especially in moist environments, a vapor. The cumulative effects of exposure to arsenic-coated wallpapers could have dire, sometimes fatal, consequences.  In attempts to remove the arsenical threat, medical professionals and chemists published medical case reports, opinion columns, and even fictional serial stories that decried the use of arsenical wallpaper.  “At-home” arsenic tests gave the public the ability to test papers for themselves rather than rely on manufacturer claims. This helped to increase awareness and encouraged consumers to make informed choices when purchasing goods.

Though some criticized the anti-arsenic contingent as sensationalizing the issue, increased public awareness ultimately sparked demand for arsenic-free goods. By the early 1880s, fashions had shifted and consumers were avoiding bright arsenical colors in favor of wallpapers using safer colors.  As a result, wallpaper poisoning was a rare occurrence by the 1890s and without a market for the toxic pigment in domestic goods, by the early 1900s the production of arsenical pigments was limited to use as pesticides, rodenticides, insecticides, fungicides and wood preservatives.

But where did society turn for a beautiful shade of green?  Though not without risks of their own, other metals-based or synthetic pigments were substituted.  Viridian, a chromium based pigment, was a common replacement for arsenical greens in wallpaper, and many modern greens are based on phthalo green, a synthetic color first produced in the early 1900s.

Vibrant, Verdant, Virulent

And what is in store for the vibrant but virulent wallpaper sample book in the NLM collection?  The book currently has a modern, non-original, cover which will be carefully removed.  Then, the book will be separated into individual pages and each page will be enclosed in its own inert polyester sleeve. The book will then be reassembled in a post-binding format.  The sleeves will not only protect the acidic, and therefore fragile, pages from mechanical damage but also protect future researchers from arsenic exposure by preventing direct contact with the wallpaper samples.  As for occupational health concerns regarding arsenic exposure during the conservation treatment process, we’ll be wearing appropriate personal protective equipment as we do anytime hazardous substances are involved. 

Read Part I and Part 2 of this series.

Like a good mystery? Discover Shadows from the Walls of Death as seen on Mysteries at the Museum “Jack the Ripper, Wooden Money, Deadly Décor” which premiered Thursday, July 12 at 10 p.m. ET/PT on Travel Channel.

Kristi Wright is a contract conservator for the Conservation Program of the History of Medicine Division at the National Library of Medicine and principal of Wright Conservation and Framing.