Final answer:
The process needed to make a clay body vitreous is firing, conducted at high temperatures around 900 degrees Celsius, where the clay particles fuse to create a glass-like, non-porous quality.
Step-by-step explanation:
To make a clay body vitreous by firing at a specified temperature, the necessary process is firing. Glazing could be used to create a vitreous surface but is, in this instance, distinct from the actual process of making clay vitreous. To vitrify clay means to fire it in a kiln at high temperatures, often around 900 degrees Celsius, which causes the clay particles to fuse together and create a non-porous, glass-like quality. This was an important step in ancient pottery practices as well as modern ceramics, and the temperature and duration of the firing were crucial for the final quality of the pottery or sculpture.
Different cultures have used various methods to work with clay, such as coiling, slab building, and pinch potting. The wetter the clay, the easier it is to shape, but also the more fragile it is. After shaping, the clay must be carefully dried and fired to achieve the desired strength and durability. During firing, decoration techniques such as incising lines, applying slipware or glazes, and painting become permanent, further enhancing the aesthetic appeal of the pottery.