The first variation of this glaze was produced in 1975-76. It contained far less
soda ash and also was based on a single particle size of nepheline syenite. The
balance between F-4 feldspar and nepheline syenite was also favoring more F-4 feldspar.
The addition of the redart clay causes the glaze to take on a more peachy tone overall.
It can be omitted and the EPK content upped by the 1% amount for a whiter result.