A. Lange & Söhne gives its perpetual calendar a glowing Lumen dial

A. Lange & Söhne has brought its Lumen treatment to the perpetual calendar. The Lange 1 Tourbillon Perpetual Calendar “Lumen”, launched at Watches and Wonders 2026, pairs the Glashütte maker's classical Saxon design with the contemporary photoluminescence usually reserved for sports watches.

The watch gives the Lumen series a calendar that can be read in the dark. The off-centre time sub-dial, the outsize date and the retrograde day-of-week indicator all take part in the nocturnal display, an area of watchmaking that has been neglected for too long.

Chief executive Wilhelm Schmid said earlier this year that the house revisits Lumen only every two to three years, and only where it makes horological sense. “The Lange 1 is a very elegant watch, whereas the ‘Lumen’ execution is rather contemporary and sporty,” he said. “If you merge the two, you have to avoid going in the wrong direction.”

Illuminating the time sub-dial was the major hurdle. Coating the Roman numerals directly with luminous compound made them look disproportionately thick by day, so the manufacture applied the material beneath the semi-transparent, UV-permeable sapphire crystal dial instead.

At night the numerals emerge as sharp, crisp silhouettes against a glowing background, while daytime legibility is undisturbed. Turning such an intricately assembled layout into a nocturnal spectacle required, of all things, deliberate restraint.

The perpetual calendar keeps its instantaneously jumping displays: the peripheral month ring, the outsize date, the retrograde day-of-week indicator and a leap-year window at 6 o'clock. The tourbillon stays on the watchmaker's side of the movement, where some would argue it belongs.

Purists may also take issue with the word “tourbillon” appearing on the dial. The movement itself carries quieter flourishes: the balance cock and intermediate-wheel cock are steel, engraved by hand with shooting stars and polished black.

They are anchored by another Lange special, a diamond endstone set in a screwed gold chaton. A.Lange & Söhne makes it its mission to keep expanding the frontiers of watchmaking, and details like this are where that shows.

A first luminous moon-phase

The Lumen edition is Lange's first with a luminous moon-phase and an integrated 24-hour day/night indicator. Its celestial disc turns once a day, moving from a clear daytime sky to a star-studded night behind the lunar disc.

The moon-phase is accurate to one day in 122.6 years. A moon-phase is also the kind of indication a wearer checks after dark, which makes it a natural candidate for lume.

Driving it all is the newly developed automatic Calibre L225.1, built from 685 parts. Lange's brief is to bring a new and improved movement with every release, and the L225.1 adds the day/night moon-phase to the perpetual calendar's existing functions.

Lange's perpetual calendars and our rankings

We have covered the jumping indications before, on the 50-piece Datograph Perpetual with its revived full-platinum bracelet. That watch had no luminous twist, which is what this edition introduces to the family of Lange perpetual calendars.

In our ranking of the best luxury watch brands, A. Lange & Söhne is firmly in the conversation with Patek Philippe, Audemars Piguet and Vacheron Constantin at the summit of haute horlogerie. We rank on heritage, in-house movement-making, value retention and design language.

Schmid's caution about merging elegance with sportiness is the watch's central tension, and the under-dial lume is the answer to it. Lange has not disclosed a price, production numbers or delivery dates for this edition in the material available to us.

The 685-part calibre, the hand-engraved cocks and the diamond endstone are all typical of the house, and so is the decision to keep the tourbillon on the movement side. More in our coverage of watches jewelry follows as details emerge.