Spin's signature Celadon White glaze gets its slight greenish blue tint from trace elements of iron-oxide, and becomes glossy once it reaches about 2450 °F (1350 °C) in our high-fire kilns. It forms the base layer for almost all of our fine porcelain pieces.
Historically Celadon White (青白) wares have a great variety of shades of greenish blue based on the quantity of iron within the glaze. Spin's wares tend to be quite white for Celadon White wares however some glaze mixes contain slightly more iron-oxide resulting a more celadon hue.
Underglaze Red is a copper oxide glaze applied underneath the celadon white glaze, which causes the underglaze to turn its distinctive red hue. It is particularly sensitive to temperature, only turning red around 2370 °F (1300 °C).
Due to irregularities of temperature within the kiln, the Underglaze Red can exhibit shades of blue, green and yellow, creating a rich, polychromatic effect. This extreme sensitivity to temperature also contributes to a successful firing rate of only 40%, which explains why Underglaze Red products are typically more expensive: many must be discarded.
China Blue is the trademark of Jingdezhen’s porcelain and the symbol of Chinese porcelain around the world. A cobalt oxide pigment, it has a distinctly bright color, stability with kiln temperature and colorfastness.
China Blue is actually black when used alone (see unglazed designs). However, when it is overlaid with our Celadon White glaze, it turns royal blue. Less sensitive to temperature than the Underglaze Red, it has a successful firing rate of 70-90%.
The effect of the crackled glaze is caused when the glaze cools and contracts faster than the body, thus having to stretch and ultimately split. Each is a unique pattern of crackles with no two exactly alike.
Since the Song dynasty's imperial court use of Guan wares in the 12th century crackled glaze has been held in high regard for its difficulty to produce and graded based on crackling pattern.
Spin's crackled glaze is a light grey with a dense crackled pattern paired against Celadon White on the remaining surface of the object.