Tall vase #2, 12" x 7" x 7", Terra Sigilatta surface
John Hull’s current work is created from porcelain thrown on the potter’s wheel and is finished with a Terra Sigilatta surface. Terra Sigilatta (earth seal) is made by mixing the throwing slip and other clays with water and allowing it to settle out for 24 hours. After settling, the finest clay particles are drawn off, mixed with water again and re-settled. This is repeated five times to enable the gathering of the absolute finest particles. This mixture is then applied to the surface of the unfired work and buffed with lambs wool and the palms of the hands until a pleasing sheen develops. The work is then fired once to approximately 1900º F and thus is porous and will not hold water. The firing makes this beautiful skin-like surface permanent. This produces a pure white or rich orange surface. The markings on the surface are then achieved by burning a variety of materials in variations of Pit and Saggar firing techniques.