A technique based on the same kind of technology used in airport scanners has revealed images beneath a fresco held at the Louvre museum in Paris.
Trois Hommes Armes de Lances was known to be a fresco forged by Giampetro Campana on a wall from Roman times.
The new research suggests that under that forgery lies a real Roman fresco.
The discovery was announced at the American Chemical Society meeting by Bianca Jackson of the University of Rochester in the US.
Terahertz waves are known for their ability to penetrate materials without damaging them, and have in recent years been added to the suite of tools used to examine items of cultural heritage.
These tools span much of the electromagnetic spectrum from X-rays to ultraviolet to the infrared - and of course microscopy with visible light.
Previous studies of Trois Hommes Armes de Lances had used X-ray fluorescence - which yields a list of all the atoms within an object - but showed that there were atoms present in the work that were not present on the surface.
Dr Jackson and her colleagues were called in to apply terahertz imaging to find out what lay beneath.
“After quite a bit of data processing, we were able to pull out some signs that there is a figure beneath… what looked like two eyes, eyebrows, nose, mouth, a shadow for a chin,” she said.
I’m finally uploading and editing my photos from the villas at Stabiae, including this exceptional example of transitional I/II Style fresco from the Villa Arianna.