The manufacturing of ceramic is part of ancient traditions of different and old populations. There are many different typologies of ceramic products. The colour of ceramic depends on the chemical element contained in the clay. The composition of ceramic is complex. Even in this case, the molecular structure of ceramic determines a different kind of material. For example the presence of water in the ceramic structure gives more plasticity to the structure and the manufacturing is easy and fruitful.
There are two main kinds of ceramic. The first typology is the Ceramic of compact paste. Usually the ceramic of compact paste is identified with porcelain and gres.
The porcelain is considered by the oriental population the most prestigious level of ceramic. The main element of the porcelain is white clay. According to studies, the porcelain was invented by Chinese population in 1700. The second typology of ceramic of compact paste is the gres.
The gres is obtained by the mixture of different kind of natural clay. The colour of gres depends on the quantity of iron elements in the composition. However, the ceramic of compact paste has a minimum level of porous structure and for this reason they are impervious to liquids and gas. This typology of ceramic is very strong and it’s impossible to scratch it.
As already mentioned, there is another typology of ceramic. This is the case of Ceramic of porous paste and in this typology are included terracotta, terraglia and maiolica.
The origin of majolica ceramic has to be referred to Majorca Island where it was discovered. Originally the ceramic was covered by glaze with tin. Furthermore, all the products of ceramic of porous paste are even characterized by soft and absorbing paste.
The colour of terracotta’s products depends on the baking. It could be yellow or red. The baking is around 980°C -990°C. The presence of iron in the composition gives strong resistance to terracotta and for this reason is used in building constructions. As regard the manufacturing of terracotta, the process has to be referred to the following steps.
First of all, before the starting of every manufacturing the most important step is the selection of the different kinds of clay.
Secondly, the manufacturing needs different kinds of modelling tools. One of them it is the modelling made by free hand. In this case, it is chosen the portion of clay and after that the favourite shape is created. In this occasion, it is possible that the manufacturer uses other instruments. The second way of modelling tool, it is called modelling with colombino. This technique is generally used for the creation of jars, bowls and dishes. The manufacturing of terracotta can even follow the modelling with mould, lathe and with sheet. Another important step in the manufacturing of terracotta is the drying. During this process the grade of humidity is not so high, so the material has to dry very slowly.
The baking is very important in the manufacturing of clay. The baking is very important because it can modify the structure of the final products. During the manufacturing, each products of ceramic has different temperature. Furthermore, the final step of the manufacturing of ceramic product is the decoration. The typical colours of ceramic are three: Ingobbio, cristalline and smalto.
Cristalline are vitreous, impervious and shiny covering. Usually they are transparent and sometimes they are coloured. When this kind of covering is used, it is possible to see the clay below. In order to decrease the melting point the cristalline need melt elements. Finally, it is possible to use the glaze that in Italian is called smalto. Even in this case the glazes are vitreous and coloured covering. The glaze has been used for many functions as for example the protection of material, for the washing, for the decoration and finally for the maintenance.