Holographic Interferometry and active infrared thermography for the nondestructive assessment of esteemed hand-painted ceramic sample panels.

Ceramics of Castelli, town in the province of Teramo – Italy – is the most famous expression of a craft tradition spread a little everywhere in the region of Abruzzo, from the Majella to the Gran Sasso. A tradition of more than a thousand years is rooted in the nature of the place: the birth of the ceramics of Castelli, in fact, is due first of all to the presence of clay in the soil around the old town, and of course the abundance of water and wood needed to fuel the furnaces in which the creations of the artisans were cooked. The rest, that is to become the great ceramic of Castelli, was created by the Benedictine monks, who first taught the pottery artwork to local craftspeople. Beautiful objects can be seen not only in the Museum of Ceramics of Castelli in Abruzzo, but also in the Hermitage in St. Petersburg, the Victorian and Albert Museum in London and the Metropolitan in New York. It is precisely for this reason that ceramics of Castelli must control its products to avoid defects. Defects in the ceramic body are usually originated during the pressing stage due to incorrect use of parameters or to improper selection of raw materials. These defects are generally characterized by the inclusion of heterogeneous materials or agglomerates, which decreases the structural strength jeopardizing the final quality of the fabricated workpiece. The use of non-destructive testing can help in detecting defective workpieces, in order to improve the quality of this production. In this work, holographic interferometry (HI) and infrared thermography (IRT) allowed the identification of real and simulated defects in a sample called “L’Arbitro” (the referee) painted using mostly yellow, green and orange, which are the typical colours of the Italian ceramics of Castelli.