Decades ago, the casting process was the predominant method for recovering three-dimensional footwear impression evidence. Although the impressions were also photographed, the bulky and less sophisticated photographic equipment, combined with the slower films of those times, made photography more difficult, less available, less convenient, and often less successful than casting. Most of the older literature on casting footwear impressions advocated the use of plaster of Paris. The casting procedure required the use of about 5 lb of plaster of Paris for the average footwear impression. This translated into an inconvenient, messy, and time consuming procedure, especially if this process had to be repeated for several impressions. In addition, and most important, because the plaster of Paris was not a sufficiently hard form of gypsum, much of the fine detail, usually necessary for positive identifications, was routinely washed away when the soil was cleaned from the cast.