Comparison of wall paintings at Ostia Antica by NMR depth profiling

Painted walls were analyzed at Ostia Antica, the ancient port of Rome, with the aim to trace the evolution of the buildings in the city. Nuclear magnetic resonance (NMR) depth profiles were acquired from walls and mortar fragments to image the stratigraphy of the mortar-layer preparations for the painted surfaces produced over more than five centuries from the second century BC to the third century AD. The profiles are compared in search of similarity to obtain clues suggesting alike workmanship and contemporaneous origin, and to retrace the transformations of execution technique in time.