iny coloured leather tesserae rise to the surface of the dial on the latest Slim d’Hermès Hippocampe. Only under magnification do the seahorse’s astonishing details reveal themselves: a sparkling black eye highlighted by a delicate touch of white, scales shimmering through subtle turquoise gradients, and a buttercup-yellow harness – a playful nod to its four-legged terrestrial counterpart.

Inspired heritage

The Hippocampe art dial, produced in two distinct executions for two numbered limited editions of 24 pieces each, brings together the innovations developed at the Brügg leather atelier under the guidance of Philippe Delhotal, Creative Director of Hermès Horloger. In a recent interview with Europa Star, he recalled the origins of the project: “In 2016 I decided that leather should take centre-stage on our dials: a first in the métiers d’art family. I proposed two designs and our leather artisans imagined two techniques, leather marquetry and leather mosaic.”

This vision gave rise in 2017 to the Arceau Cavales, whose leather marquetry dial paved the way for the Arceau Robe du Soir. The latter’s leather mosaic dial went on to win the Métiers d’Art Prize at the 2018 Grand Prix d’Horlogerie de Genève, prompting the Hermès Horloger teams to push their explorations even further.

Marquetry and mosaic: two instruments, one melody

Ancient mosaics are to archaeology what the horse was to human mobility for centuries: indispensable. Whether laid on floors or adorning walls, these colourful compositions – often inspired by Greco-Roman mythology – testified to the wealth and status of their owners. Today, rediscovered through preventive excavations, they continue to captivate archaeologists and museum visitors alike, from Naples and Tunis to the galleries of the Louvre. They also remain a recurring and emblematic decorative motif within the Hermès universe.

During our visit to Brügg, we met Élisabeth, one of the craftswomen involved in developing both techniques from the very beginning in 2016. She explains the distinction between marquetry and mosaic: “In marquetry, every piece is unique and belongs to one specific place. In mosaic, every tessera has the same size and shape; only colour determines where it goes.” The Arceau Robe du Soir, the maison’s first leather mosaic project, required close to 2,500 leather squares, each measuring just 0.5 millimetres on a side.

The Arceau Robe du Soir, the maison’s first leather mosaic project, required close to 2,500 leather squares, each measuring just 0.5 millimetres on a side.

The song of leather

The six craftswomen*, all of whom have now mastered marquetry and, for two of them, leather mosaic as well, are remarkably versatile. They divide their time between creating art dials and producing leather straps from start to finish, from cutting the hide to executing the signature hand-sewn saddle stitch.

The workshop rings with a crystalline soundtrack. Small polished, rounded hammers are used to soften the leather seams, producing a distinctive, almost musical sound.

Adjacent to the leather atelier, the hide storage room holds a wealth of surprises. Shielded from all external light and maintained under strictly controlled humidity conditions, it houses the three classic skins used in watchmaking: Louisiana alligator, calfskin and goatskin. Dozens of wooden shelves fill the roughly one-hundred-square-metre space, where hundreds of labels identify each hide by type, colour and finish.

“Barolo” designates an alligator leather processed in one of the maison’s Italian tanneries. “Swift”, widely used for Hermès leather straps, is a premium calfskin. Then there is “Barenia”, instantly recognisable for its substantial thickness and warm brown-orange hue, which evolves throughout its exceptionally long lifespan, earning it the internal designation of “Heritage”.

The labels also reveal the breadth of the maison’s cultural inspirations: Athena Glycine calfskin, matte Eglantine pink or Brume blue alligator, Evercolor Casaque red calfskin. Together they form an almost limitless palette of more than 4,000 distinct combinations of materials and colours.

Shielded from all external light and maintained under strictly controlled humidity conditions, it houses the three classic skins used in watchmaking: Louisiana alligator, calfskin and goatskin.

A craft shaped by constraints

Unlike wood marquetry, leather cannot be sanded, meaning that every element of the future dial must be cut with absolute precision from the outset. Furthermore, the material’s natural flexibility can lead to deformation during assembly, a challenge that only experience can truly mitigate. Finally, the perfectly flat surface required for the passage of the watch hands imposes a maximum uniform thickness of just 0.5 millimetres.

The mosaic craftswoman then glues and places each leather tessera individually. “We cannot prepare a layer of glue in advance,” we are told. “It dries too quickly.”

Out of these constraints emerges the magic of craftsmanship. As the work progresses, the artisan selects the tessera that appears most appropriate. Where does turquoise begin? Where does carmine end? Here, only the craftswoman’s artistic sensitivity determines the final result, which varies subtly from one dial to another, and from one artisan to the next.

At an earlier stage, it is sometimes necessary to revisit the original artwork itself. A cheerful tiger painted against an exuberant background by artist Alice Shirley lost much of its expressiveness when only its head was rendered in mosaic on the dial. The artist therefore created a second composition focused entirely on the tiger’s face.

Out of these constraints emerges the magic of craftsmanship. As the work progresses, the artisan selects the tessera that appears most appropriate.

The future of tradition

Originally developed within the Brügg leather atelier in 2016, these two decorative crafts are now mastered by six specialists. The precision of the gesture and the perseverance demanded by any métier d’art are learned within the workshop itself, with the more experienced craftswomen playing a pivotal role in this informal transmission of knowledge.

From a technical standpoint, both crafts continue to evolve in response to the growing intricacy of the designs entrusted to them. For the Panther model, for example, whose production concludes this year, leather threads were used to create the whiskers, each one individually inlaid into the composition.

The latest Slim d’Hermès Hippocampe stands as the culmination of a decade spent refining and consolidating this artisanal expertise. Here, leather marquetry and leather mosaic engage in dialogue with engraving. A finely sculpted gold applique recreates the principal contours of the creature’s skeletal structure. Much like in champlevé enamelling, the leather tesserae are positioned around and between delicate metal partitions.

The result perfectly illustrates Philippe Delhotal’s philosophy: “Innovation is always possible, and never at the expense of tradition.”

Here, only the craftswoman’s artistic sensitivity determines the final result, which varies subtly from one dial to another, and from one artisan to the next.

*With five women and one man working in the atelier, the feminine form is used throughout the remainder of this article.