"Li Tre Libri dell'Arte del Vasaio," by Cipriano Piccolpasso, [AD 1559], is a book that describes the formulas and methodologies used by the Italian craft shops in the 16th Century. Cipriano Piccolpasso, in this book, has divulged the secrets of that art, and for this, he risked his life.

Here I want to describe the process I followed to obtain my reproductions in 1990

Clay, sand, barrel tartar, antimony, copper oxide, lead, cobalt, iron oxide, manganese.
Working process:

- The first step, getting the right clay from the river, or any place rich in this material, and create the piece.

- From the river, we take the sand, and from the (empty) wine barrels, we obtain the barrel tartar, a strong acid that mixed with sand allows it to melt at a lower temperature, 900°C, instead of 1600°C.
- Cooking this mixture of sand and tartar (900°C), you obtain a Marzacotto, a semitransparent glazed sponge-like mineral.
- The marzacotto is finely ground at the mill and mixed with water together with tin oxide, to get white enamel.
- The piece (terracotta) is glazed by immersion in the gloss obtained.
- The preparation of the colors has the same components and procedure of Marzacotto, plus the oxides for the different colors.
  These also are finely ground at the mill.
- After the painting process, the piece is glazed with transparent glaze by immersion or spray, and then it's ready for the kiln.

The result (eventually) is a piece that has the same characteristic as those stored in the museums.

I only forgot to mention the most crucial component: a powerful passion for this art.