One morning, you bring up your old diver. The light catches the curved glass, and there, surprise: the deep black of its dial has taken on a warm and velvety chocolate shade. This is not an illusion. It's patina, the word that collectors pronounce with the same smile as lovers of great Bordeaux (my preference has been Burgundy for several years but I imagine that you don't care much, dear reader). Why do some dials change color over time? The answer lies in a discreet ballet between chemistry, light and materials — and says a lot about our relationship to authenticity.
The majority of vintage dials were not designed for chromatic eternity. Their color, their shine, their markings result from a stack of layers sensitive to the outside world.
This slow chromatic shift is rarely uniform. This is what creates, when the watch has lived coherently, an “organic” patina that the eye judges to be harmonious.
In the 50s and 70s, many sportswomen – divers and chronographs – used UV-sensitive lacquers and varnishes. Exposed to the equatorial sun, these black dials gracefully turned brown, sometimes even dark caramel. This so-called “tropical” metamorphosis concerns both diving icons and pilot times. It is explained by the photo-degradation of the binder and the progressive transparency of the black layer, which reveals the warm tone of brass or a burnished undercoat.
For a long time, nighttime readability was ensured by radium paints, then tritium. As they age, these compounds lose their shine, oxidize, and take on vanilla to apricot shades — the famous “pumpkin”. The contrast with the dial gives the illusion of a warmer dial, and, when indexes and hands age together, the whole gains a sought-after chromatic coherence. Warning: a relume that is too perfect often betrays a modern intervention.
The “gilt” dials (“negative” inscriptions revealing the golden brass under a black lacquer) change mood over time: the black becomes browner, the lettering becomes copperier. Galvanized dials can lose their luster and turn slightly, especially when the protective varnish thins. As for glossy lacquers, they are the most theatrical: micro-cracks, increased transparency, warmer reflections — the patina becomes a story.
Not everything is poetry. There is a fine line between patina and damage. The informed collector observes:
On the market, a beautiful natural patina – this deep “tropical brown”, without stains, with intact legibility – can increase the price. It gives character and uniqueness, two cardinal values for amateurs. Conversely, a redial dial, an approximate reprint, or a relume that is too new, tend to penalize the object.
“Service dials” — replacement dials fitted during official service — restore the watch to its original appearance, but erase part of its history. Some collectors see it as necessary for mechanical and aesthetic hygiene; others regret the loss of this unique patina. The reasonable path? Transparency. Document the interventions, keep the original parts, and let the buyer make an informed judgment.
Faced with the public's love for these lived-in nuances, contemporary houses have chosen the path of controlled patina. The smoked dials—gradient from light in the center to dark at the edges—play up depth and warmth without cheating. Tinted varnishes and modern, more stable pigments offer browns, greens or blues that evoke time without suffering its ravages. We do not “age” the watch; we compose with light to obtain a similar, controlled and lasting emotion.
Why do some dials change color? Because they live. The sun, the air, the skin and the years interact with fragile and noble materials. A few decades later, the result can be an accidental masterpiece: a black that becomes cocoa, a lume that turns to honey, a silver that takes on a gray pearl patina. This beauty is neither perfect nor reproducible. She reminds us that in watchmaking, time is not just a measurement: it is a pigment.
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