Lacca

Lacquer in watchmaking is not just one material: it's a family of techniques ranging from Japanese plant resin to modern synthetic compounds, with radically different processes and results. Confusing them is the most common mistake I see, even from people who've been selling watches for years.

The ancestor is urushi, extracted from the sap of the Toxicodendron vernicifluum tree, cultivated in East Asia. In its raw state it's highly toxic. After filtration and refinement, it's applied by hand to the dial in successive layers, each sanded before the next. Hardening occurs through moisture absorption from the air, not evaporation: this explains why drying times reach two months. Over the years the surface becomes harder, not more brittle. Kurono Tokyo, among the few who use it systematically today, records the highest scrap rate on urushi dials of their entire production: a single dust particle during drying is enough to reject the piece.

More elaborate techniques derive from urushi. Shibo-urushi mixes the resin with pigments and egg white, obtaining a viscous paste that the craftsman can model; sanding, tin powder or shell fragments complete the pattern. Maki-e, literally "scattered picture," involves sprinkling microparticles of gold or silver onto still-fresh lacquer: it's among the most difficult Japanese decorative arts to master, practiced today by very few masters. A final coating of transparent suki-urushi seals everything.

In the Western context the term lacquer indicates different products. Zapon is a single-component lacquer applied by hand to galvanic dials to protect them long-term — in the HYT Hastroid Rainbow, lacquerer Yan Patriarca applies it in multiple layers to build a progressive chromatic effect. Vintage gilt dials exploit transparent lacquer as a selective mask during galvanic plating: black varnish adheres only to exposed metal, leaving brass-colored characters in relief. On modern dials like the Jaeger-LeCoultre Polaris Chronograph, 35 layers of transparent lacquer stacked together generate color gradients that no rapid industrial process can replicate.

The fumé effect and degradé are variants of the same principle: lacquer hand-sprayed at increasing concentrations toward the perimeter, so the center appears lighter and the edge more saturated. A technique simple to describe, difficult to execute uniformly at production scale.

A warning from the bench: visible bubbles under the lacquer in Tudor Submariner ref. 7016 Mk2 — the so-called bubble dials — are neither negligible defects nor desirable characteristics in themselves. They arise from water infiltration or porosity in the substrate. Collecting has mythologized them, but they indicate an execution or preservation problem, not an intentional variant.