The classic method of analysis (not just of the surface) of paintings is radiography which can detect Pb, Hg and Cd in pigments. In the last 20 years, two new methods, infrared reflectography (IR), which detects graphite (drawing), and neutron activation autoradiography (NAAR) have been added. The authors examined the use of NAAR, which can identify about 30 different chemical elements. Their methods and results are described and discussed. They found that only 3 of 10 to the 10th power Co-atoms became radioactive after 3 days of radiation, which showed that only a small portion of the substances present in the paint layer were activated. They found no documentable damage. Documentable changes in the binding media of the paint layer were first discernable at 40 Mrad.