A wooden panel, found in Hexham Abbey after bring lost for more than 30 years, could be the missing piece in a series of medieval panel paintings, according to art conservators.
The painting is thought to be part of the Dance of Death sequence, a set of four surviving wooden panel paintings from around 1500.
These depict Death visiting powerful figures, including a cardinal, a king, an emperor, and the pope.
In 2017, a wooden panel, unseen since the 1990s, was discovered in Hexham Abbey's triforium, a rarely visited area due to its inaccessibility.
The panel was in poor condition, with a heavily discoloured surface.
Dr Theodorakopoulos conducted an examination using a camera developed by spectral imaging specialists XpectralTEK.
This camera uses a wide range of wavelength bands from across the electromagnetic spectrum, from the near ultraviolet to the infrared, to capture different layers of an artwork, from surface varnishes, through the various paint layers, to the underdrawings beneath.
By merging images of the panel taken at three wavelength bands representing red, green, and blue light, Dr Theodorakopoulos was able to identify the image hidden beneath decades of grime – a figure in Tudor dress, thought to be the 'caller' featured on the introductory panel in the Dance of Death series.
Dr Theodorakopoulos said: "The investigation involved non-destructive multispectral imaging, which allowed us to examine the paint layers without extracting samples from the panel.
"The discovery of this panel that may belong to the Dance of Death series of paintings is a monumental achievement for Hexham Abbey and for art conservation.
"This is not only a rediscovery of an important piece of art history, but it also demonstrates the potential of modern technology in unlocking the secrets of our cultural heritage."
The study also involved statistical analysis to simulate the removal of discoloured varnish, enabling the team to virtually restore the painting's vibrant colours.
Dr Tom Kelsey of Hexham Abbey added: "The technical skills that Dr Theodorakopoulos and Northumbria University brought to our investigations cannot be underestimated.
"Melding together the spectral analysis and the history of the Abbey’s medieval art collection has proved so helpful – and will be of enduring interest to many academics and interested observers."
The research was carried out in 2018 in partnership with Hexham Abbey Conservation Group and will now feature as a case study in a webinar being given by Dr Theodorakopoulos and XpectralTEK, taking place on Wednesday, April 30, at 3pm.
Antonio Cardoso, CEO and co-founder of XpectralTEK, said: "Spectral Imaging linked to AI as a cloud-based solution is today used from agriculture to materials identification and study in a surface.
"In this particular case, XpeCAM contributed to gaining a deeper understanding of the materials' surface, bringing to light most of the information hidden by time."
The possible existence of a fifth painting in Hexham Abbey’s Dance of Death series had been discussed for hundreds of years.
A sketch by John Carter from the 1790s depicts an identical figure to that hidden on the rediscovered panel.
It is not known for certain whether there were originally additional images in the sequence in addition to those housed in Hexham Abbey.
Hexham Abbey's Dance of Death panels are considered some of the most important surviving examples of medieval English panel painting, a genre that was particularly vulnerable to destruction during periods of religious reform, such as the Protestant Reformation in the 16th century.
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