Some books are just toxic
But it's not necessarily the content that makes you sick
THEY say you should never judge a book by its cover, but some are being judged too dangerous for the reading public simply because of their colour.
Before we begin to foam at the mouth over the prospect of censorship, there’s apparently a very good reason for it. The books in question are toxic, in more than a rhetorical sense. No, not the content – but the bindings. These are books that can literally make you sick.
Appropriately, perhaps, these tomes are coloured green. But not every volume of such hue is bad for the health; some are perfectly fine. It all depends on whether arsenic was used to create the vivid emerald green bindings.
Therein lies the problem. Short of invasive and time consuming chemical testing – how does one know? For safety’s sake, then, green books have been locked away. Until now.
A new scanning device has been developed at the University of St Andrews in Scotland that offers a fast and low-cost means of identifying toxic pigments in the bindings of historic books. The groundbreaking tool makes it easier to distinguish hazardous tomes from those that are safe to handle and display.
The new portable device was developed Dr Graham Bruce and Dr Morgan Facchin, from the university’s School of Physics and Astronomy, in collaboration with the Libraries & Museums department.
“The retention of green books from public view is not only a matter of safety, but it also restricts access to the information contained,” said accredited conservator, Erica Kotze, who instigated the programme.
“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.”
Facchin said: “Our device shines different colours of light onto the book. The amount of light reflected at each colour is like a fingerprint of the pigment in the book. Through extensive work using books from the university’s collections, our team have found a way to identify the fingerprint of emerald green on a book.”
Arsenic was in common use in the 19th Century for use in pigments. Publishers used it to create the colour known as emerald green, but it was also used in wallpapers and textiles.
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.
Restricted access
Recently, libraries and collections from around the world have had to prevent access to parts of their book collections for this reason. In 2024, The Guardian reported the French National Library was placing books suspected of containing arsenic under “quarantine”.
Testing is available, but until now it been a specialised, costly, and time-consuming process, leading many institutions to simply prevent access to all suspect green books from their collections as a precaution.
Last year the The University of Bielefeld, along with several other German universities, isolated around 60,000 books as a precautionary measure.
“The project began with the need to positively identify emerald green bindings in the University of St Andrews collections, using the analytical techniques available to us within the university,” said Dr Pilar Gil, heritage scientist from University Collections, who lead the research.
“A device used in the School of Earth Sciences to detect minerals in rocks was the starting point, and the Eureka moment was discovering the unique reflectance pattern from emerald green pigment in the visible spectrum. The idea was then to apply this discovery to an instrument which we could use and share with the sector.”
Bruce added: “The device that we have developed is handheld and allows us to screen an individual book for the presence of emerald green pigment in a fraction of a second. It has been exciting to see it being used in libraries and collections across Scotland. Our team has been asked to look at thousands of books, of which over 100 have been identified as containing emerald green pigment.”
It is hoped that this tool will enable public and private institutions both large and small to accurately identify poisonous books in their collections.
“This work is a brilliant example of how universities and research can solve real problems,” said Dr Jessica Burdge, assistant director in Libraries and Museums.
“The emerald green detection tool is the result of a collaboration that plays to the strengths of different expertise across the university and takes advantage of our fortunate position to have access to expensive analytical equipment, to create something simple easy and cheap for others to use.”
MC