Clous de Paris is a surface decoration of small raised pyramids lined up in neat rows. Done the traditional way, it is engraved into the metal with a guilloché machine rather than stamped onto it. Watchmakers use it on dials, movement bridges and cases, and Patek Philippe uses it on Calatrava bezels.
How is Clous de Paris made?
Traditionally, the pattern is cut on a guilloché machine. Two kinds are used: the rose engine and the straight-line engine. Either way, the pattern is engraved into the metal, not stamped onto it. Watchmakers took up this kind of guilloché decoration for dials, movement bridges and cases. Patek Philippe makes the decoration on each hobnail bezel by engine turning, which is a type of guilloché engraving.
What does Clous de Paris look like on a dial?
On a dial, Clous de Paris gives a raised, three-dimensional texture. Each pyramid is a small relief, so the surface has high points and low points across its rows. The English name, hobnail, comes from this look: the pattern resembles the studs on old metal objects. A finer version, with smaller pyramids, is often used on dress watches. There, a subtle look is wanted.
Which Calatrava has a hobnail bezel?
The first Calatrava with a hobnail bezel was the ref. 96D of 1934. The D stands for décor. On a Calatrava bezel, the pattern forms two rings of tiny pyramids, one inside the other. The best-known hobnail Calatrava is the ref. 3919, which came out in 1985. Its case measures 33.5 mm and is only 6.5 mm thick.
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