low contrast leaf prints at cone 6
Glazes are fired at cone 6 in an electric kiln.
The kiln is cooled slowly, at a rate of 25 deg F an hour in the temperature interval 1750 deg F to 1650 deg F, with a 1 hour hold at 1650 deg F.
Here are leaf prints on two cobalt glazes, and two low alkaline glazes.
The same wash is used on the leaves for all four pots. The difference in the color of the wash shows the effect of the interaction of the wash with the base glaze.
The first two glazes, containing cobalt have bases high in alkali metals, and magnesia, moderate strontia, and low zinc.
The first glaze is higher in soda, lower in Lithia than the second.
These glazes belong to the family of mixed pink and blue cobalt glazes. I was looking for a glaze where the pink would dominate.
Instead the strength of the pink and blue color seems matched, so that glazes in which the blue is a pale pastel tint
the pink also is washed out and sometimes sufficiently pale as to seem white.
The leaf wash contains rutile, which is the cause of the yellow green tint in the leaf prints.
The second pair of glazes containing nickel, have bases low in alkali metals, moderate in calcia, and high in magnesia and strontia.
These glazes also contain some boron.
The first glaze is lower in magnesia and higher in strontia than the second.
Here I was looking for a glaze with a smooth surface, good for utilitarian ware, which would stay put, so take a sharp leaf print.
In that both of these glazes succeed, but have cracks which are not crazing, so have glaze fit problems.
In each pair the two glazes are more similar than different.
The two cobalt glazes
glaze zincSr_182_1 on a bowl diameter ~5 inches
glaze zincSr_182_2 on a bowl diameter ~5 inches
Note the multiple dunting cracks in this pot.
The two low alkaline glazes
glaze loAlk_182_0 on bowl ~5 inch diameter
glaze loAlk_182_1 on a bowl ~5 inch diameter