Seeing Through Pasteovers

During a visit to the Chester Beatty Library in Dublin, Ireland, in September 2022, our researchers made a remarkable discovery. While analysing Arabic manuscripts with regard to the inks used in them – the aim was to determine whether iron-gall, carbon, or mixed inks were used to produce the documents – they found, by chance, that an additional layer of paper had been applied to the original cover sheet of the manuscript. They then analysed the document using infrared reflectography (IRR), a non-invasive imaging method that is mainly used in the examination and preservation of paintings. With the help of IRR images, it possible to see beneath the surface layers of a painting or, as in this case, a manuscript. This method revealed that underneath the upper layer was a text that was no longer visible.

The chance discovery sparked a pilot study in which further Arabic manuscripts with laminated pages were analysed for hidden text. These manuscripts are in the collection of Leiden University Library, where the study was carried out in November 2023. Kyle Ann Huskin from the CSMC, Boris Liebrenz from the University of Leipzig and Karin Scherper, a conservator at Leiden University Library, were involved in the study.