- Bookbinders historically used a toxic mixture of arsenic and copper to create the bright green color on book covers.
- Toxic books have been kept from public access in libraries and museums due to health hazards.
- University of St. Andrews Libraries and Museums developed a device for detecting the toxic green pigment.
Thousands of books believed to be toxic have been quarantined at museums and libraries worldwide. Now a new tool promises to give some of them their freedom — and restore access to would-be readers and researchers.
The issue is a colorful one: emerald green, as a matter of fact. Bookbinders in the past were fond of using arsenic mixed with copper to create a bright green that was used in book covers and some inlay features of book covers.
The new device to check for the presence of the toxic pigments was developed by the University of St. Andrews Libraries and Museums in Scotland and the university’s School of Physics and Astronomy.
As the university explained in a news release, “Although it has long been known that historic wallpapers and textiles, particularly those colored a vivid green, may contain arsenic, the focus in recent years has been on bright green-colored book bindings. This is because publishers used arsenic to achieve a vibrant green color known as emerald green. While the risk to the public is low, frequent handling of these books can lead to health issues like irritation of the eyes, nose and throat, and potentially more serious effects, causing concern for those who handle books on a regular basis.”
Many, many libraries have responded to the risks by putting suspect books where they can’t be reached, in part because testing has been expensive and time-consuming. Instead, libraries have just moved such books out of access points to be careful. The University of Bielefeld in Germany, for example, did that with 60,000 books.
Shining a light on books
St. Andrews’ researchers wanted a way to ensure their own book collection was safe and started with an analytical device that the School of Earth Sciences used to identify minerals in rocks.
The “Eureka!” moment was discovering the unique reflectance pattern from emerald green pigment in the visible spectrum,” said lead researcher and professor Pilar Gil, Heritage Scientist from University Collections. “The idea was then to apply this discovery to an instrument which we could use and share with the sector.”
Two other professors, Graham Bruce and Morgan Facchin of the School of Physics and Astronomy, developed a portable tool. The device shines different lights on the books, and the amount of light reflected at each color identifies the book’s pigment. “Through extensive work using the university’s collections, our team has found a way to identify the fingerprint of emerald green on a book,” Facchin said.
Bruce said it takes just a fraction of a second, making it possible to scan a great number very quickly.
Said Erica Kotze, a University of St. Andrews book conservator, “The retention of green books from public view is not only a matter of safety, but it also restricts access to the information contained. This means that the books which have been tested and found not to contain the pigment can remain available to users. This project has been an interesting collaboration and has been well-received by colleagues in the sector who will be able to more accurately target collections which need special handling.”
Impact of arsenic
It’s not believed the arsenic would do much harm to someone who came across such a book casually, which means risk to the public is low. But for those who handle old books a lot or researching such books and handling them, the risk goes up. There’s a possibility of eye, nose and throat irritation, as well as more serious effects, per the release.
The Occupational Safety and Health Administration said that serious health consequences can include skin lesions, warts and discoloration, an increased risk of lung, bladder and skin cancers, risk of heart disease, cognitive decline in children and could even be fatal, though it’s unlikely that handling a green book normally would lead to that.