Flow blue (ceramic glaze)

Refers to a glaze comprising a transfer-printed blue design on white porcelain or stoneware, characterized by the design taking on a soft, feathery, blurry, or fuzzy-edged appearance, as if the blue had bled into the white ground. It was created by firing the work in an atmosphere containing volatile chlorides, which caused the blue pigment to become diffused through the glaze. The glaze was an early 19th-century development, originally in Staffordshire; it was popular throughout the English and American Victorian and Edwardian ages. The blue may range from grayish blue to greenish blue, but the most desirable is a vivid cobalt blue.