"Outside of Japan and China we do not know where any colors and glazes are to be found finer than those which come from the Rookwood Pottery."
- Clarence Cook, in The Studio
Rookwood was well known for their devotion to underglaze slip decoration, a technique based on the Barbotine ware seen by founder Maria Longworth Nichols at the 1876 Centennial Exposition in Pennsylvania. Within that tradition, the company introduced a number of specialized glaze lines of exceptional quality around the turn of the century for which they earned lasting fame. Rookwood continued to innovate in the early 20th century, before their business was affected by economic woes tied to the Great Depression.
Standard Glaze was the first glaze produced by Rookwood in the 1880s and helped the company achieve early recognition for their techinques and the fine quality of their decoration. Heavily reliant on the pigmentation of native clay deposits in Ohio, the Standard Glaze was known for its warm earthy tones, in particular yellow, orange, red and brown, rendered under a brilliant clear glaze.
Introduced in 1894, the Iris glaze was described by Rookwood in a promotional booklet as "deliciously tender." The clear high gloss glaze over the slip decoration offered a stark, photorealist effect, often on a base of white clay. Iris allowed for unlimited color effects and was generally used to depict naturalistic floral and botanical motifs, and rarely landscape scenes. In 1899, the Black Iris variation was introduced.
Opalescent in nature, the Sea Green glaze lent itself to imagery of undersea flora and fauna in shades of in blue, green and gray, though sometimes the glaze would be employed for floral motifs. Sea Green was introduced in the mid 1890s alongside the Iris glaze.
In 1904 Rookwood introduced the Vellum glaze, a hybrid between the transparent gloss glaze and a matte finish. The nature of the Vellum glaze lent itself to scenes that reflected the American Tonalist movement, and it was generally used to depict quiet landscapes marked by hazy atmospheres, a stream or pond bordered by trees, and scenes depicting shifting quality of light. Rookwood won a Grand Prize at the 1904 World’s Fair in St. Louis for a vase in the Vellum glaze.
Distinguished by the absence of gloss, Rookwood introduced this line of glazes around the turn of the 20th century, including 'Conventional Mat,' 'Modeled Mat,' and 'Incised Mat." In these new styles, the glaze was no longer used merely to protect the underglaze decoration but instead became the main focus. The Matte glazes lent themselves to more Modernist decoration and flattened forms. As described in a promotional booklet published by the firm in 1904, these glazes combined "richness of color with softness of texture."
Introduced in 1902, Rookwood's Architectural Faience was often used to create mantelpieces as well as tiles and pictorial plaques which adorned the exteriors and interiors of public and private buildings. Shortly after it was introduced, Rookwood received a commission from the New York City IRT Subway System to decorate a number of stations, including the 23rd Street Station, 86th Street Station, and Wall Street Station. A monumental pictorial plaque by Rookwood remains on display at the Fulton Street Station. Rookwood tiles can also be found in Grand Central Station.