cobalt free blue

Mixed with an alkaline potassium-base glaze, rutile and copper carbonate combine to make a beautiful turquoise blue in cone 6 oxidation.

I like the central colour the most, which is a 50/50 ratio of copper carbonate to rutile. I dipped the terracotta body in a Maiolica glaze for a brighter body response:

Maiolica glaze recipe:

Quartz, 6

Borax Frit, 62

Hyplas ball clay, 9

China clay, 9

Whiting, 3

Nepheline Synite, 5

Zircon, 11

The alkaline base in this low-temperature neutral firing gives a heavily crazed surface, so I won’t use it for domestic ware, but I used it along with other colouring oxides to decorate this bowl inspired by the streets of Paris.