In 1972, with new technology becoming available, Yale sent the map for chemical analysis by forensic specialist Walter McCrone whose team, using a variety of techniques, found that the yellowish lines contain anatase (titanium dioxide) in a rounded crystalline form manufactured for use in pale pigments since the 1920s, indicating that the ink was modern. They also confirmed that the ink contained only trace amounts of iron, and that the black line remnants were on top of the yellow, indicating that they were not the remains of a penciled guide-line, as the British Museum staff had speculated.