Susy Siegele and Michael Haley have been working with colored clay since 1976 when they became interested in developing colored clay bodies while they were ceramics students of J. Brough Miller at Texas Women's University. Michael did his Master's of Fine Arts thesis using colored clay in the raku technique at about the same time Susy began experimenting with a series of colored porcelain bodies for high-fired work. They soon began marketing laminated colored porcelain dinnerware, which continues to be the mainstay of their business.

Besides giving workshops for other potters, Susy and Michael volunteer their time to do clay, papermaking, and drawing classes for the local elementary schools and Headstart program. Their pieces are in the collections of all the Russian cosmonauts who have orbited the Earth.
Nearly all of their work is slab constructed although they spent a couple of years doing wheel-thrown wood-fired pieces in the late 1970's while Michael was employed at a living history museum in Dallas recreating late 19th century salt glazed utilitarian ware. They are still under the influence of woodfiring, although it is now used only during the later stages of the firing process (from 1600 degrees through 2400 degrees) to take advantage of the flashing and consistent temperature and reduction that wood affords.

Although they have experimented with ceramic stains, the colorants they consistently use are raw oxides that are plugged into the clay body. Currently they are mixing about thirty shades of porcelain containing various amounts of red and yellow iron, cobalt, chrome, and granular ilmenite. These clays are stacked, sliced, extruded, or otherwise manipulated as they are constructed into loaves that weigh up to two hundred pounds, which are then sliced into thin slabs from which dinnerware is made.

Source: http://nmaa-ryder.si.edu/collections/exhibits/whc/whc-intro.html