CNN_ Classical Greek marble sculptures today appear crisp and white. But they weren’t always that way, according to a new study, which found the famous 2,500-year-old Parthenon sculptures were colorful, painted with floral patterns and other elaborate designs.

By using a noninvasive imaging technique, researchers at the British Museum — where nearly half of the sculptures reside — and King’s College London found traces of paint on 11 out of 17 figures and from a section of frieze on show in the museum, according to a study published this week in the journal Antiquity.

Paint often does not survive on archaeological finds, particularly in cases such as the Parthenon sculptures that date back to between 447 and 438 BC and were continuously exposed to the environment, said lead study author Dr. Giovanni Verri, a conservation scientist at the Art Institute of Chicago who previously was a fellow at the British Museum.

“These are just thin paint layers at the very, very top of the surface of these objects, and so they are at the interface between everything that happens. … (The paint) is the first to get the impact of the environment,” Verri said. “It’s also possible that during conservation treatments — restoration treatments — these small traces that looked like dirt effectively, were inadvertently removed.”

Greece has repeatedly called for the return of the sculptures that British diplomat Lord Elgin removed from the imposing Parthenon temple in Athens in the early 19th century when he was ambassador to the Ottoman Empire, which then ruled Greece.

Infrared light detects traces of long-lost paint

The technique used to find the paint was created in 2007 by Verri and is known as visible-induced luminescence imaging. The process uses infrared light that finds microscopic traces of paint that the eye cannot see, Verri said. By illuminating the sculptures with the red light, a pigment known as “Egyptian blue” absorbs the light and appears on camera as a glowing white.

“Egyptian blue” was a popular pigment of its time that was made using calcium, copper and silicon, according to the Royal Society of Chemistry. The bright blue was highly valued for its rarity and was commonly saved for royalty or depictions of gods and goddesses.

The distinctive blue was found in several places in the marbles, including the serpent tail on the sculpture of mythical king Kekrops, within the background space of statues Demeter and Persephone and on the garment worn by Dione, mother of Aphrodite, where the forming of two flower petals was found near the bottom of the cloth, according to the study.

“The interpretation of these very small traces is always complicated,” Verri said. “So, we make suggestions (of these patterns) through comparisons with other works of art.”

The researchers also detected a purple color that was not found through the imaging process but by the human eye, Verri said. The hue, which they named “Parthenon purple,” is particularly unique, the study said, because researchers found that it was not made using shellfish — the common ancient Mediterranean recipe.

Shellfish-based purple can be detected using a technique called X-ray fluorescence, Verri said, but that color was not present in this case.

Classical texts refer to an elusive purple color, the study added, but the ingredients weren’t disclosed because the color was deemed so valuable.

“This recent study gives more proof that colorful decoration was common in ancient Greek art,” said Michael Cosmopoulos, a professor of archaeology and Greek studies at the University of Missouri–St. Louis, via email. He was not involved in the study.

“This is a big deal because it challenges the traditional Western idea that classical art was just plain white marble and shows how important color was to ancient Greek artists. … These findings help us understand the creative process behind, as well as the meaning of the Parthenon and its sculptures.”

At this stage, a reconstruction of the sculptures’ original appearance “is not really possible,” Verri said, since the imaging technique only detected blue paint, and “because reproducing in modern terms one of the greatest masterpieces of mankind is not something that can be addressed lightly,” Verri added.

The study also found that there were no signs of keying or abrasion to the sculptures that are typically seen to help paint adhere.

“What we were able to really demonstrate is not specific surfaces for the application of paints, but rather that both carving and color were conceived as part of the same objective,” said William Wootton, an author of the study from King’s College London. “Extreme care and attention in the production of sculpture — both its carving and its color — actually was visible across the ancient world to a level which we are still only beginning to understand.”

The study points to earlier instances when Greek sculptures were found to be colored, such as in 2008 when conservators at the Acropolis Museum in Athens found a greenish pigment on the West Frieze featuring a horseman.

Verri said he hopes that further imaging will soon be developed to find other colors present on the sculptures.