A. Lange & Söhne’s Lange 1 Tourbillon Perpetual Calendar “Lumen” Turns Darkness Into A Design Triumph
The platinum-cased limited edition proves that legibility after dark can be technically intriguing and genuinely elegant.
Darkness has always been the enemy of fine watchmaking. A finely decorated dial is crafted to reward close attention under good light. But what happens when the lights go out? In true A. Lange & Söhne fashion, darkness is welcomed as a challenge to overcome.

Since 2020, Lange has released seven models under the exclusive “Lumen” series, featuring highly luminous watch components that emanate an ethereal glow under semi-transparent smoked sapphire dials.
The latest addition to the family, the Lange 1 Tourbillon Perpetual Calendar “Lumen”, entices collectors with the same playbook and then some. Limited to 50 pieces, the watch’s platinum case houses a tourbillon and an instantaneous perpetual calendar, both rendered legible in the dark through a semi-transparent dial.
The Lumen’s draw works less like a decoration, and more like a mechanism in its own right. The translucent sapphire crystal lets ultraviolet light pass through to charge the luminous compound beneath.
To fully harness the power of light, Lange prioritises the Lange 1 Tourbillon Perpetual Calendar “Lumen”‘s essential components for maximum exposure: the outsize date, retrograde day display, month display disc, running seconds, moon phase, leap year indicator and outline of the regular time displays.
In the dark, the larger elements glow with pronounced intensity while finer ones such as the hands and the scales take on a subtler wash of light. The most captivating detail sits within the moon-phase display, which shows a starless sky by day and a field of luminous stars by night.
Rather than replacing the sapphire dial and adding luminous components to an existing model, Lange has developed a new movement specifically for this iteration.
The Calibre L225.1 features a tourbillon with a stop-seconds device built around a V-shaped arresting spring that Lange patented in 2008, which halts the balance within the rotating cage so the watch can be set to the second.

The perpetual calendar shares that same instinct for no-nonsense functionality. Its month indication runs on a rotating ring around the dial’s circumference rather than the small aperture found on most calendar watches. Elsewhere, its date, day, month, and leap-year indications switch instantaneously rather than crawl forward overnight.
Lange has long made the argument that decoration and function are the same pursuit. With the Lange 1 Tourbillon Perpetual Calendar “Lumen”, that commitment receives a glowing affirmation.





