For anyone interested in soda or salt firing, Soda, Clay and Fire covers the topic in great detail. The technical research and presentation surpass all existing literature on the topic, and the rich, vibrant examples of finished work are stunning and sure to inspire. With soda firing, the creative process continues until the kiln is turned off. Nichols’ book discusses the principles behind this technique and delves into clays, glazes, loading protocols, firing schedules and more. Also included are profiles of other artists working with this technique and examples of their work.
Phases are specific forms of materials. The most familiar phases are solid, liquid and vapor. Any phase of a material is identical in composition and structure in all parts of that phase. For instance, a glass of water is the liquid phase of H2O, top to bottom; if it weren’t, we’d call it something else, like ice if it were solid (structural change), or lemonade if it had lemon and sugar dissolved in it (compositional change).
Barium carbonate has long been used as an ingredient in high-fire glazes, sometimes conferring unique properties upon glazes. One of the alkaline earth carbonates, it has also been used as rat poison (large doses can be toxic to humans as well). Glazes containing it ought to be checked for barium leaching if they are intended to hold food or drink, or reserved for surfaces that do not come into contact with food. It is not my intent to present the research on barium toxicity here, but to present a course of action for replacing it in glazes.