Two non-destructive techniques for data and authentification of easel paintings are based on the study of compositional changes that lead white undergoes over time, due, on the one hand, to the mode of preparation of the pigment, and on the other, the place of origin of the mineral. Nuclear microprobe analysis of impurities in lead white allowed to measure percentages of copper and silver in 15th to 20th century works. However, the equipment limitations in detecting impurities will need to be set back to widen the application of this method. The isotopic variation measurement ²⁰⁶Pb/²⁰⁴Pb using mass spectrometry on 15th to 20th century paintings allowed to state that the same European mine was used throughout the 15th to the 18th century, whereas starting in the 19th century the ore came from further and further locations. -- AATA