An ancient Roman painting that remained buried in volcanic ash for nearly 1,800 years has only just revealed its true beauty.
Scientists have used a new type of high-resolution imagery to give life to the artwork, which had long been forgotten after one of the most famous volcanic eruptions in history – Mount Vesuvius in 79 AD.
The eruption is more often associated with the destruction of the ancient city of Pompeii, but Herculaneum – a town that would have been located near modern-day Naples – was also greatly affected. It was buried under 66 feet of volcanic material (20 metres) until its rediscovery by archaeologists in the 19th century.
As they entirely covered the city's artworks – including the delicate painting of an ancient Roman woman - the layers of volcanic ash and molten lava actually preserved them for centuries. Ironically, excavations from the second part of the 19th century greatly degraded the quality of these masterpieces.
Humidity, changes in temperature, salt and other atmospheric agents have caused great harm to the frescoes, paintings and statues that were discovered over the years by archaeologists and retrieved from the ash.
The portrait of the young Roman woman was excavated 70 years ago. At the time, it was probably still a beautiful piece of art, but exposure to the elements has greatly degraded it – to the point that in recent years, it has become impossible to see what was on the canvas with the naked eye.
In a study presented at the 254th National Meeting & Exposition of the American Chemical Society, scientists have explained how an innovative x-ray technology has allowed them to save the young woman from decay.
Bringing the woman back to life
The researchers used a recently developed portable macro X-ray fluorescence (macro XRF) instrument, to scan and analyse the painting. It is a particularly helpful method as it is non-invasive – the painting can be analysed without the device touching it and without having to move it.
More interesting for art conservators is the fact that the machine can map the chemical elements that remain present in the painting, such as iron, lead or copper.
"These insights could help conservators choose cleaning solvents that are compatible with the elements in a painting and possibly allow much of its original magnificence to be restored," said Eleonora Del Federico, a scientist with the Herculaneum Conservation Project, who worked on this research.
Using the technology in this way to identify the kind of chemical elements in the painting, the researchers were able to recover a lot of the details that had made it stunning in the first place.
They found that the artist had used an iron-based pigment to sketch the woman. Her eyes were then highlighted around her eyes with a lead pigment. There were also high levels of potassium identified near the woman's cheeks, which indicates that a green earth pigment was probably used as an underpainting to help create a "flesh" colour.
"Science is allowing us to get closer to the people who lived in Herculaneum. By unravelling the details of wall paintings that are no longer visible to the naked eye, we are in essence bringing these ancient people back to life. And learning more about the materials and techniques they used will help us to better preserve this artistry for future generations," Del Federico concluded.
"This young woman is gone forever, but our study has revealed in remarkable detail her humanity, her thoughtful expression and her beauty."