Identifying ‘toxic’ green books
Drs Graham Bruce and Morgan Facchin, together with colleagues in Libraries and Museums, have developed a new instrument that can help cultural heritage institutions distinguish which books in their collections may contain a toxic pigment, and which are safe to use and display.
It has long been known that historic wall papers and textiles, particularly those coloured a vivid green, may contain arsenic. However, the focus in recent years has been on bright green coloured bookbindings. This is because publishers used arsenic to achieve a vibrant green colour known as emerald green, or copper acetoarsenite. While a passing interaction with one of these books presents a low risk, 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.
Recently libraries and collections from around the world, including the French National Library in 2024, have had to prevent access to parts of their book collections. Whilst testing is available it has, until now, 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 University of Bielefeld, along with several other German universities, isolated around 60,000 books as a precautionary measure.
The handheld instrument developed in St Andrews measures the reflectance spectrum of the bookbinding at key wavelengths, allowing a user to screen an individual book for the presence of emerald green pigment in a fraction of a second. It has been deployed in libraries and collections across Scotland this year: the team have inspected thousands of books, of which over 100 have been identified as containing emerald green pigment.
While removing the arsenical books from general circulation improves the safety of staff and readers, books which have been tested and found not to contain the pigment can now remain available to users, preserving access to their content.
The project recently received significant media attention, featuring on BBC Scotland news and in several national newspapers. The work is also the subject of the exhibition Poisonous Books, Dangers from the Past, which has reopened at the Wardlaw Museum in St Andrews since Friday 6th June 2025 and runs until the end of July. Admission is free
More information can be found at the project website: https://poisonous-books.wp.st-andrews.ac.uk/