Marguerite Wildenhain vase, 1960's/Pond Farm, Northern CA~from fleabay. Wildenhain was born in France and studied ceramics at the Bauhaus before relocating to the united states in 1940 and joining the Pond Farm school/artist colony near Guerneville-north of San Francisco where she lived and worked till her death in 1985.
She fired everything to cone 5, in an oxidizing atmosphere. Her active surfaces and glaze effects were achieved by the interaction of fluxes in the engobes and the particles of iron and manganese in the clay body. Effects that I expected to be the result of a reducing fire were obtained in oxidation, and the basic methods have never had to change. Richard Petterson, Ceramics Monthly, march 1977.