Using x-ray light, a team of researchers hopes to expose the writing hidden under 2,000-year-old burnt papyri from Herculaneum.
Scholars have been attempting to interpret what remains of highly burnt scrolls retrieved from the library of a luxury villa destroyed during Mount Vesuvius’ eruption in 79 AD for more than 200 years. The disused scrolls were flash-heated and transformed into fragile rolls of carbonized papyrus resembling lumps of coal or burned logs, and the hot gases turned the library into an oven in which the abandoned scrolls were flash-heated and transformed into fragile rolls of carbonized papyrus resembling lumps of coal or burned logs.
The site was first excavated in 1709, but it was abandoned after that. Around 1,800 scrolls were discovered in 1980, and they were donated to the Biblioteca Nazionale in Naples, the Institut de France in Paris, the British Library in London, and the Bodleian Library in Oxford. Scientists are currently trying to figure out how to read anything unintelligible and hidden inside a complicated matrix of tightly coiled, blackened, and compacted material that is too fragile to touch, with writing that fades quickly when exposed to air.
Physically traditionally opening these scrolls causes substantial and irreversible damage to the original materials. Various methods have been used throughout the years, including immersion in water, pouring mercury through the rolls, and suspension in various gases. Currently, the standard procedure is to carefully cut away the firm outer layers before attempting to separate and unroll the more flexible middle layers. Even under ideal conditions, much of the text will be lost in the process, leaving just a partial trace of the original.
The Diamond Light Source synchrotron is used in the first stage to investigate the scrolls with x-ray beams. These extremely strong x-rays may penetrate the scrolls and map their interior structure in a non-destructive and non-invasive manner. The x-rays flow through the scrolls and are detected on the other side, resulting in a succession of two-dimensional photographs that can be patched together to form a three-dimensional model of the scroll.
Prof. Seales is the director of the University of Kentucky’s Digital Restoration Initiative, a research program devoted to the development of software tools that allow the recovery of fragile, unreadable documents. Seales claims that Diamond Light Source is a critical part of our long-term strategy for revealing writing from damaged materials because it provides unrivaled brightness and control over the images we can make, as well as access to a team of experts who understand our problems and are ready to help us succeed. Ancient texts are uncommon and valuable, and they can’t be deciphered with any other method currently available. We are prepared to take a huge stride ahead in our capacity to understand and visualize this material because of the opportunity to study the scrolls at Diamond Light Source, which was made available by the National Endowment for the Humanities and the Andrew Mellon Foundation. The scan session is shaping up to be a pivotal moment in our search for a trustworthy technique to access the invisible library.
DATA ACQUISITION, ANALYSIS, AND VIRTUAL UNROLLING IN MICRO-COMPUTED TOMOGRAPHY
The second stage involves the papyrus fragments left over from previous attempts to physically unroll the papyri. These bits, which have apparent text on them, are photographed, scanned, and the results are fed into computers.
Although micro-CT has just been commercially accessible for a decade, it is perfectly suited to the examination of papyrus scrolls. The scans provide a non-destructive way to view the inside of the scrolls without having to physically open them. As a planning and condition evaluation tool, CT can be extremely beneficial. It reveals fracture lines within the scrolls, as well as any other damage concealed within the artifact.
To educate the computer to recognize the minute structural variations between the inked and darkened areas, complex computer methods (machine learning) are used (such as differences in the structure of papyrus fibers).
After the computer has been trained on these pieces, it will be applied to the data from the intact scrolls obtained at Diamond Light Source in the hopes of revealing the hidden content.
A computer simulation may digitally unfurl a scroll, exposing its original form, given a high enough resolution scan and the capacity to separate layers within a scroll. If the ink and papyrus contrast, the ink features can disclose the original text without the need for invasive and destructive physical unrolling. Such software and algorithms have been developed by scientists and tested on a variety of proxy objects. The Herculaneum papyri, on the other hand, provide distinct obstacles to this approach.
The first micro-CT scan of Herculaneum papyri has been collected, permitting imaging of the interior of these scrolls without risk of serious damage. The interior structure of the rolls, including fissures, fractures, and air gaps, may be seen in these images. Any physical intervention or conservation plan for these papyri could benefit from this knowledge. The complexity of this internal structure has hindered initial data analysis. It’s been nearly impossible to use automated segmentation to separate layers within scrolls. Although no link has yet been visible, manual segmentations have been successful in viewing small areas of the scrolls.
Luckily, this non-destructive scanning procedure caused little to no damage to the scrolls, conserving them for future study. We know our “virtual unrolling” method works based on CT scans of similar objects, and if a procedure to boost ink contrast can be devised, another scan could disclose a lot more concealed text.
