List of Pottery Terms - O

O

• Once-fired, green-fired (W)

• Opacifier An ingredient used in glazes to cause it to be opaque, and hence mask the colour of the underlying body.

• Orton cones See pyrometric cone.

• Overglaze (W) See Enamel, above.

• Oxidation (W)

• Oxidizing firing A firing in a kiln that retains an oxygen environment.