I had the opportunity to learn a new technique by participating in Fresco Painting Workshop at Loulé Criativo | Portugal – SENART The Sky is the Limit.
Learning to preparing the tile and making the “fresco plaster” with limestone. 
Adding the “Fresco” limestone plaster to the tile. 
Painting with pigments on the fresh limestone plaster.
Fresco (plural frescos or frescoes) is a technique of mural painting executed upon freshly laid (“wet”) lime plaster. Water is used as the vehicle for the dry-powder pigment to merge with the plaster, and with the setting of the plaster, the painting becomes an integral part of the wall. The word fresco (Italian: affresco) is derived from the Italian adjective fresco meaning “fresh”. The fresco technique has been employed since antiquity and is closely associated with Italian Renaissance painting.
Defintion of Fresco – Source: https://en.wikipedia.org/wiki/Fresco