Two Englishmen invented the basic process that is used to make Prosser molded beads. In 1840 Richard Prosser patented the process in England, and in 1841 his brother Thomas patented improvements to the process in the US. Both patents were for the manufacture of buttons. Neither of the brothers ever made beads. Prosser beads are also called Bapterosses beads, after a French entrepreneur who further improved on the Prosser method and began making beads in France in the 1860s.
Prosser beads are always opaque, and their ceramic-like finish is often rather crude and grainy. They come in a limited range of colors beyond the standard spectrum of light to dark primary colors, the usual pastels, and a few more exotic hues such as amber and coral. Predominantly spherical or cylindrical and modest in size, they could be described as typical filler beads. Thanks to interchangeable two-part molds, however, Prosser boast a variety of complex shapes, including interlocking beads, such as “snake” beads.
Prosser beads are made with the help of a hydraulic press that can exert the great pressure that is needed to compress a cold, moist mixture of finely pulverized materials into cast-iron molds and form beads. After removal from the mold the beads are dried, then after being fired at a relatively low temperature they may be hand painted or transfer printed, but they are usually left undecorated and monochrome. Finally, they are glazed and fired at a high temperature, similar to the way that porcelain is.
The ingredients of the mixture and their proportions vary, and researchers debate whether Prosser beads should be classified as ceramic—porcelain, in particular—or glass, or a ceramic/glass hybrid. The materials that make up the mixture reportedly include clay or some other earthy material (the basic material of ceramics), flint and feldspar (porcelain ingredients), but also soda and quartz sand (major components of glass). Metallic oxides (used by potters and glassmakers alike) are added to obtain the desired colors. Other beadmakers have added still other ingredients to the mix, most notably milk which was introduced by Bapterosses. It is understandable that Prosser beads are sometimes misidentified as pressed glass beads, or mistakenly called porcelain or earthenware beads. They are also widely known as tile beads, because the same materials and technology are used to make ceramic tiles.
Beads that are made by the Prosser method share several distinguishing features. Mold seams often create pronounced equatorial ridges on spherical beads. Cylindrical beads taper slightly, as do their large perforations, which makes it easier to release them from the mold. A marked difference between the two ends of cylindrical beads is due to the molding process. One end is typically smooth and somewhat rounded, while the other end is flat and displays a pitted “orange peel” surface. In Bapterosses beads, which tend to be more carefully crafted, this tell-tale anomaly may barely be visible except to a trained eye.
After Bapterosses developed a system to mass produce Prosser beads, and thus reduced their cost, they became very popular. Soon other workshops and factories began producing Prosser beads in Bohemia, then in Germany, and possibly in Italy and even in England. Because the beads were inexpensive and uniform in size and shape they became worldwide best sellers. European beadworkers liked to use them to create decorative geometric designs to embellish utilitarian items, such as table mats, trivets, and bell pulls. But most Prosser beads were made for export to the Americas, to Asia, which inspired the name “Oriental Beads” for a line of trade beads, and especially to Africa, where they were used in the regalia of Kuba kings and Luba diviners. The high frequency of Prosser beads found in Zaire, the former Belgian Congo, suggests that they may have also been made in Belgium. The great bulk of them were cylindrical or spherical in various sizes, but some were specifically designed for the African market. The Czechs used the Prosser method to mold imitation conus shell rings, lions’ teeth, and Tuareg amulets. Today these simulations of traditional African ornaments are highly prized collectibles.
In the late 19th and early 20th century, shipments of Prosser beads arriving in African ports rose to hundreds of tons annually. But when plastic beads proliferated in the 1950s and ‘60s, demand for Prosser beads declined, and by the end of the 20th century production of these beads ceased altogether in Europe. They continued to be made in North Africa, however, with old machinery that had last manufactured Prosser beads in the Czech Republic. The equipment had been sold off by weight to a Moroccan company, and in the 1990s it was still turning out tile beads, but in modern matte and muted colors favored by contemporary designers.