Typically our earthenware pieces undergo two kiln firings. Initially a bisque firing to around 1080 degrees Celsius followed by a glaze firing to around 1030 degrees Celsius. This process particularly relates to most underglaze, majolica & crystal glaze finishes. However where lustres & gold are employed, a third or even a fourth firing at lower temperatures is required.
Porcelain items on the other hand vary immensely. Any given piece can have a minimum of one-two firings to achieve a fairly simple design while other more complex pieces can sustain up to twenty or more firings. The possibilities are endless & extraordinary.