These two showcases illustrate the many demanding phases for the creation of a Florentine mosaic, also called “commesso”. The first step consists in tracing the original painted model, at a 1:1 scale: this phase is carried out by the craftsman in charge of the realization of the mosaic. The different sections that are going to compose the final image are drawn on the tracing. The next step consists in finding the right colors for the transposition of the original painting into stone. The desired tonalities are chosen from thin slabs, section-cut from semiprecious hard stones. On the selected stone slab a paper template is fixed with a special glue; the shape of the piece of stone is then cut out by means of a chestnut wood bow. Once the cutting of the sections is completed, these are refined with files along the borders, to guarantee the perfect matching of the pieces. They are also levelled on the back, so that they all have the same thickness. On the back a slate is fixed with resin-wax glue as an invisible support, to strengthen the artwork. The same kind of glue is used to join the adjacent stone sections together. The final step consists in the polishing by means of differently ground abrasive powders rubbed onto the surfaces. This procedure gives the stones a long-lasting mirror-like shine, which is a specific aspect of these fascinating artworks.
