SYDNEY, AUSTRALIA—Working with the people of the Jawoyn culture, Barbara Stuart, Alexandria Hunt, and Paul Thomas of the University of Technology, Sydney, are analyzing the chemistry of ancient rock art in Arnhem Land to understand how the materials were used by the artists, and how their techniques changed over time. “We need to take samples but we try to take as small amount as we can so that we don’t visually alter the paintings at all,” Hunt told Phys.org. Her tests, employing the infrared beam at the Australian Synchrotron in Melbourne, will determine what the pigments were made from. “Once I have that information I’ll be able to work out the age of the paintings,” she explained.