The original painting (left), along with images made using three different modalities. Using a combination of three advanced imaging techniques, scientists from UCLA and the National Gallery of Art have produced a highly detailed analysis of a second-century Egyptian painting.

The scientists refer to their new blended technique — which combines hyperspectral diffuse reflectance, luminescence and X-ray fluorescence — as "macroscale multimodal chemical imaging." It enabled them to learn about what raw materials the artist used and the order in which they were applied. It also uncovered insights about the painting's connections to other work from the same era.

As published in the journal Scientific Reports, the researchers were able to map molecule and element signatures across the painting's surface for each pixel of the image. This allowed important details of the painting's composition and structure to be revealed.

The painting being examined, which depicts an Egyptian noblewoman, is a Fayum portrait — a type of painting that was attached to mummies and is believed to represent the image of a real person. It measures just 35 centimeters tall by 12 centimeters wide.

Analysis revealed that the painting was made using the encaustic technique, wherein a mixture of pigment and melted beeswax is "burned in" to a wooden base.

"The decoration of her garment is an excellent example of craftsmanship in real life being reflected within the painting," noted Roxanne Radpour, a UCLA graduate student and a co-author of the study. "Madder dye extracted from roots was often used to color textiles and leather in ancient Egypt, and we see from the chemical mapping of the portrait that the artist chose to paint the noblewoman's dress with madder lake pigment, thus imitating contemporary practices."

"Without even taking a minute sample from the painting, we mapped out detailed information that tells us exactly what materials were used, and how they were prepared," said UCLA's Ioanna Kakoulli, a professor of materials science and engineering and co-director the university's Molecular and Nano Archaeology Laboratory. "We were also able to link their production technology to other ancient 'industries' and practices, such as mining, metallurgy, pottery, dyeing, pharmacopeia and alchemy."

Kakoulli said the new approach could potentially be used in other disciplines such as environmental, geological, biological and forensic sciences.

"Our approach will revolutionize the way important and irreplaceable archaeological materials are analyzed and interpreted," she added.