|Monthly Tech-Tip |
This is GA10-B Alberta Slip tenmoku glaze over L3954N black engobe (top half and inside of mug). The body is H550 buff speckled stoneware. The glaze only contains 2% added iron oxide and the engobe under it has 10% black stain, only a reduction atmosphere could produce this metallic effect with so little colorant.
This is the same piece in sunlight and a fluorescent flood lamp. The picture was taken by an iPhone and then cropped to a white background using the path tool in Photoshop. The whole mug is glazed with GA10-B. The inside and upper outside of the leather hard piece was engobed using L3954N.
A method of firing stoneware where the kiln air intakes and burners are set to restrict or eliminate oxygen in the kiln such that metallic oxides convert to their reduced metallic state.