Cloisonné is not a single technique: it is a containment system. Before anything else, I define the image's boundaries with thin metal strips or wires — almost always gold, sometimes silver — soldered onto a base. Those wires are the cloisons, the partitions that trap each color in its place and prevent adjacent enamels from fusing during firing.
The working sequence is rigid. I prepare the base, normally in solid gold or silver. I bend the wires with tweezers, micromillimeter by micromillimeter, following the design. I solder them. Then the filling begins: colored glass powder, applied with a brush into the cells using natural-bristle brushes, layer after layer, with a furnace firing between each pass. Temperatures range between 800 and 900 °C, depending on the enamel formulation. The number of firings varies greatly: twenty passes are standard in relatively simple cases, forty or fifty in complex dials. Vacheron Constantin reported over fifty hours of work and 220 gold wires for a single Eternal Flow dial. Patek Philippe used more than twenty meters of wire and 48 colors for a table clock. Louis Vuitton documents 80 hours for certain Escale dials. These numbers are not marketing: they reflect a process that cannot be compressed.
The rejection rate is high. A dial that cracks in the final furnace is a dial lost. It is estimated that only 10% of pieces advanced in production pass all firings without defects. No paint or digital printing carries this risk, and no paint or digital printing maintains color unchanged for decades as vitreous enamel does.
Cloisonné distinguishes itself from champlevé because in champlevé the cavities are created by carving the base metal, while here the partitions are built on top. It distinguishes itself from plique-à-jour because the latter has no permanent rear support: the cloisons hold the translucent enamel in the void, like a stained-glass window. Flinqué and guilloché instead concern the engraved support beneath transparent enamel. Each of these techniques has its own logic; cloisonné is the one that allows maximum chromatic complexity in defined spaces, which is why it is associated with figurative scenes and polychrome motifs.
The technique has Persian roots, entered China around the 15th century, and reached its highest technical density there. Swiss watchmaking imported it as an auxiliary craft at least from the 19th century, entrusting it to specialist enamelers — a figure separate from the watchmaker and jeweler — of which today there are fewer than twenty at a high level worldwide.