Enameling

Enameling is one of the few watchmaking techniques that offers no forgiveness: every imperfection is visible, every firing is irreversible. It consists of fusing vitreous metal oxides onto a solid surface — almost always copper, gold, or silver — through one or more kiln firings. The result is a material that does not fade, does not scratch as easily as lacquer, and maintains its color for centuries if properly cared for.

The fundamental distinction is between grand feu and petit feu. Grand feu fires at temperatures above 800°C, often exceeding 900°C; the enamel fully vitrifies and bonds to the base permanently. Petit feu works at lower temperatures, around 500-600°C, and is used for overlaid details — text, numerals, secondary decorations — that would not withstand a second high-temperature firing without melting or running. In the Breguet Classique Souscription 2025, for example, the white background is grand feu, the black Arabic numerals are petit feu: two materials, two firings, two different thermal regimes on the same dial.

Within grand feu there are constructively distinct techniques. In cloisonné, thin gold wires are soldered to the base to form cells containing different colored enamels: each cell is a sealed compartment, and the wire line remains visible as a graphic element. In champlevé, conversely, the cavities are created by engraving or milling the metal itself; the enamel fills the recesses and the original metal surface remains exposed between areas. Paillonné inserts thin metal leaves — paillons — between layers of transparent enamel, creating internal reflections that change with the angle of light. Flinqué applies transparent enamel over a guilloché base: the engraved pattern remains legible through the vitreous layer, with a depth effect. Plique-à-jour is the most extreme technique: transparent enamel is held by metal cells with no support on the back, like a stained-glass window. The dial is permeable to light. It is also extremely fragile.

For a grand feu black dial, up to thirty layers of pigment may be needed, each fired separately. For a smoky effect like H. Moser's Purple Haze, the master enameler blends the pigment by hand before firing, more concentrated at the edges, more diluted at the center. For the moon disk of Brodbeck Guillochage's 28MPR at Fleurier, multiple firings are followed by hours of manual polishing. Coquille d'œuf — eggshell — instead involves enamel powder applied by hand to separate surfaces, with surface tension controlled layer by layer.

At the bench, I have seen grand feu dials emerge from the same kiln in completely different ways. Temperature is one variable, but so are ambient humidity, pigment granulometry, and thickness of application. There is no automation that can replace the master enameler's eye before the kiln.