Discovering an Inscription
When viewed from just the right angle under specific lighting conditions, portions of an inscription could be seen at the upper left. Usually, conservators use infrared reflectography or x-radiography to see changes or buried paint layers. In this case, none of the conventional imaging techniques yielded useful information about this inscription.
However, a technology called Reflectance Transformation Imaging (RTI) helped to decipher the inscription by exploiting variations in the surface shape at the edges of the inscription.Next: Reflectance Transformation Imaging (RTI)