Tour à réduire was a specialized technique that allowed a large scale, detailed model or sculpture to be duplicated, with an incredible amount of accuracy, as an object at a much reduced scale. Large sculptures could become miniature figural pieces, brooches, bracelets, etc. The result had the look of hand chasing with an amazing level of detail and relief. These clearly defined details could be reproduced without the necessity of acquiring special skills and without the need for other craftsmen or master engravers to work on a piece.
A Russian invented lathe to produce coins by a reducing method was known to have been used at the Moscow Mint c.1700s. Based on the Moscow model, a succession of reducing machines with different mechanisms were developed by the French, culminating in a much improved machine c.1899. This new improved French model was put into use at the the French mint. Rene Lalique, among others, experimented with this reducing lathe, known as the tour à réduire, and soon even those without specialized training were able to create fabulous medal jewels with all the detail of a hand engraved piece.
Lalique adapted the tour à réduire from its intended use - engraving coins - to making brooches and later branched out to make other jewelry objects in this manner. His uses for the lathe included low relief ivory pieces, horn and large gold items such as chalices and caskets.
Lucien Janvier (Parisian jeweler and sculptor - a contemporary of Lalique) specialized in the technique. Once other jewelers discovered Lalique's secret for achieving these magnificent jewels Janvier was so swamped with work that he was forced to enlarge his workshop. The creation of Art Nouveau medallist jewelry, sculptural jewels and objet d'art were greatly facilitated by this technological innovation of the late nineteenth century.