Shining a Light on the A. Lange & Söhne Lumen Collection

When A. Lange & Söhne makes a contribution to watchmaking, whether in the areas of technology, design, materials, or any combination of these or other elements, it tends to go above and beyond the call — to challenge itself to reach a little higher, to put its own distinctly Saxon spin on things. This philosophy is evident particularly in the brand’s approach to complications: not just a moon-phase, but a moon-phase that’s accurate for more than a century. Not just a tourbillon, but the first tourbillon with a stop-seconds mechanism. Not just a split-seconds chronograph, but the first “triple split” chronograph to make comparative time measurements of not just seconds and minutes but multiple hours. 

It was in that overachieving spirit, no doubt, that Lange developed its own signature illumination system for watch dials, rolling it out in 2010 on the second generation of the groundbreaking Zeitwerk model that it had introduced the year prior. The system, called “Lumen” and patented in 2013, illuminates not only dial elements like hands and indexes in the dark but also components normally hidden beneath the dial’s surface, like date disks and decorated plates, wheels and bridges. Lange’s technical solution to the challenge of charging all of the elements uniformly — luminous-treated surface details like hands, hour markers and subdials, as well as non-treated parts beneath the surface — was a dial made of sapphire and coated with a semi-transparent substance that blocks most of the visible spectrum of light but allows light in the ultraviolet (UV) spectrum to pass through it.

Like other of the manufacture’s exclusive innovations — like its proprietary precious-metal alloy, Honey Gold, more on which below —  Lange has been somewhat stingy with the use of Lumen, restricting it thus far only to a half-dozen timepieces in strictly limited editions, released over the course of a decade-plus. Here is a full rundown of the A. Lange & Söhne Lumen collection, with some detail on what makes each one distinct from the rest. (All prices listed are based on the MSRP at the model's release; prices may vary widely on the secondary market.)

2010: Zeitwerk Luminous

Price: $91,000, Case Size: 41.9mm, Case Height: 13.1mm, Lug to Lug: 49.7mm, Crystal: Sapphire, Water Resistance: 30 meters, Movement: Manually Wound Caliber L043.3

The A. Lange & Söhne Zeitwerk made the scene for the first time in 2009, winning that year’s Aiguille d’Or grand prize at the Grand Prix d’Horlogerie Genève, the prestigious “Oscars of Watchmaking.” With a design based on the famed Semper Opera House clock in Dresden, near the company’s hometown of Glashütte, the Zeitwerk displays the time digitally, on a series of three numeral disks that jump precisely at the changing of each minute and hour. On the original Zeitwerk, only the large numerals are visible, in their parallel apertures linked by a framing “time bridge,” and sharing the dial space with a small seconds subdial and an analog power reserve indicator. On the Lumen version — actually called the Zeitwerk “Luminous,” as the Lumen terminology had yet to be coined — the dynamic movement of the three date disks is visible beneath the semi-transparent sapphire dial. Particularly eye-catching (and ear-catching) is the start of each hour, when all three disks jump by a single interval with a soft, satisfying click. The ghostly green glow of the dial is emphasized and contrasted by the “time bridge” in black PVD-coated German silver. This first Lumen edition established the template for the next three to follow: its case was made of platinum, it contained an in-house, manually wound movement (in this instance, Lange’s Caliber L043.3), and it was a limited edition of 100 pieces — up until 2024, the rarest in the Lumen series.

2013: Grand Lange 1 Lumen

Price: €59,000, Case Size: 41mm, Case Height: 9.5mm, Lug to Lug: xxmm, Crystal: Sapphire, Water Resistance: 30 meters, Movement: Manually Wound Caliber L095.3

Much of the modern-day mystique of A. Lange & Söhne centers around its signature timepiece, released at the launch of the brand in 1994, the unconventional and now-iconic Lange 1. As I explore in much greater detail here, the Lange 1 has since spawned its own burgeoning product family, which was joined in 2003 by the Grand Lange 1 model. Conceived as a “big brother” to the original 38.5mm Lange 1, the “Grand” model has a 41mm case and a dial architecture carefully retooled to harmonize with the increased dimensions. The 100-piece “Lumen” limited edition of the Grand Lange 1 debuted in 2013, boasting the first “oversized” date display that glows in the dark. The semi-transparent sapphire dial is offset by an outer ring and two overlapping subdials — one for the hour and minute, the other for the running seconds — made of blackened silver, and an analog power-reserve indicator at 3 o’clock that also glows bright in the darkness. In addition to the UV-permeable dial, Lange took additional steps to optimize the legibility of the large date, a hallmark of its collection, even immediately after the daily switching operation. The “tens” disk, which advances only once every 10 days, was coated with white luminous paint and printed with black numerals; while the units disk, which advances daily, uses the same black-printed numerals on transparent glass, situated over a luminous background. Of course, the areas around the subdials are transparent and luminous, allowing a view of details like the date disks and the high-end finishing on the movement, the in-house manually winding Caliber L095.2. Like the Zeitwerk “Luminous,” this second Lumen edition, limited to 200 pieces, sported a platinum case and an alligator leather strap with a platinum buckle.

2016: Grand Lange 1 Moon Phase Lumen

Price: €69,000, Case Size: 41mm, Case Height: 9.5mm, Lug to Lug: xxmm, Crystal: Sapphire, Water Resistance: 30 meters, Movement: Manually Wound Caliber L095.3

For its third entry in the Lumen series, in 2016, Lange turned to the moon-phase-equipped version of the Grand Lange 1 to establish the first fully luminous lunar display on a watch. The in-house movement inside the 41mm platinum case, manually wound Caliber L095.3, drives the timekeeping functions as well as the ultra-precise moon-phase, which uses photorealistic laser-cut moons and laser-cut stars, both on a two-layer disk that rotates in a large aperture in the subdial at 9 o’clock in sync with the actual orbit of the moon — making a complete rotation every 29 days, 12 hours, 43 minutes and three seconds. (Most watches with moon-phases round this cycle down to 29.5 days, which enables a simpler but less precise depiction of the lunar phases.) In this Lumen version, the second one limited to 200 pieces, the phosphorescent pigments applied to the moon and stars soak up UV rays through the semi-transparent dial, resulting in a miniature depiction of the night sky that shines in darkness. The outsize date in the dial’s upper right sector is also luminous, along with the power-reserve indicator at 3 o’clock. Beneath the dial, the date disk and other mechanisms can be glimpsed, bathed in ghostly green.

2018: Datograph Up/Down Lumen

Price: $100,500, Case Size: 41mm, Case Height: 13.4mm, Lug to Lug: xxmm, Crystal: Sapphire, Water Resistance: 30 meters, Movement: Manually Wound Caliber L951.7

A. Lange & Söhne introduced the Datograph Up/Down in 2012 and chose the multi-complication timepiece as the base for the fourth Lumen edition in 2018, maintaining the 41mm platinum case and limiting the production run to 200 pieces. The array of functions that are illuminated in low light consist of a flyback chronograph, an outsize date display, and the power-reserve indicator. The “Up/Down” in the model name refers to the layout of the latter, with an analog hand pointing toward the German-language scale that runs from “Auf” (“Up,” or fully wound) to “Ab” (“Down,” or empty). The hour and minute hands are rhodiumed and filled with luminous substance; the same substance entirely coats the chronograph sweep-seconds hand, enabling the wearer to use and read the stopwatch in the dark. Two subdials, one for the running seconds, the other for elapsed chronograph minutes, also emit a lime-green glow along with the ⅕-minute track and tachymeter scale along the dial’s edge. The disks for the oversized date, here positioned at 12 o’clock, directly above the blued, central hour and minute hands, soak up light through the dial as they do in this watch’s predecessors. The movement is Lange’s manual-winding Caliber L951.7, with an integrated chronograph function that can make accurate measurements to ⅕-second, and which features a host of decorations executed in Lange’s familiar Saxon style, including Glashütte ribbing on the plates and bridges, heat-blued screws, and a hand-engraved balance cock; while some of these adornments can be glimpsed from the dial’s transparent front, many others are more prominently displayed through the clear sapphire pane in the caseback.

2021: Zeitwerk Honeygold Lumen

Price: $145,000, Case Size: 41.9mm, Case Height: 12.6mm, Lug to Lug: xxmm, Crystal: Sapphire, Water Resistance: 30 meters, Movement: Manually Wound Caliber L043.9 

Unveiled on October 24, 2021, the anniversary of the first modern A. Lange & Söhne watch collection’s launch in 1994, the Zeitwerk Honeygold Lumen is the first in the Lumen series to use the proprietary Honey Gold alloy, rather than platinum, for the case. Honey Gold first appeared in Lange’s lineup in 2010 and its composition is still a closely guarded secret, though the company says it is harder than traditional gold and achieves its warm gloss, somewhere between traditional yellow gold and rose gold, through a special heat treatment and mineral additives. Here it is used for both the case (41.9mm) and the buckle on the watch’s alligator leather strap. Like the platinum version that had preceded it more than a decade prior, this 200-piece limited edition incorporates three numeral disks for the precisely jumping digital time display and a blackened German-silver time bridge, as well as a subdial for small seconds at 6 o’clock and a semicircular “Af/Aub” power-reserve indicator at 12 o’clock. Speaking of the power reserve, this model also introduced a new in-house movement to the lineup, the manually wound Caliber L043.9, which doubles its predecessors’ running autonomy to a full three days, or 72 hours. Also new on this version of the Zeitwerk is the pusher at 4 o’clock that enables separate switching of the hours, separately from the minutes, which are controlled via the crown at 2 o’clock, making for an easier and more precise time setting.  

2024: Datograph Perpetual Tourbillon Honeygold Lumen

Price: $145,000, Case Size: 41.5mm, Case Height: 14.6mm, Lug to Lug: xxmm, Crystal: Sapphire, Water Resistance: 30 meters, Movement: Manually Wound Caliber L952.4

Lange went big for its celebration of the Datograph collection’s 25th anniversary in 2024, introducing the sixth (and at just 50 pieces made, most exclusive) edition of the Lumen series, the Datograph Perpetual Tourbillon Honeygold Lumen. Like its non-Lumen predecessor in 2016, this high-complication watch integrates several of the Saxon manufacture’s signature mechanisms — a flyback chronograph with a precisely jumping minutes counter; the hallmark “outsize” date display; a perpetual calendar with an ultra-precise moon-phase (deviating by a single day only once after 122.6 years), and with all indications controlled by a single rapid-adjustment button; and a one-minute-rotating tourbillon inside a filigreed cage, equipped with Lange's world-first stop-seconds mechanism, introduced in 2008, which enables the tourbillon to be stopped for precise setting of the movement. What’s new on this model — as you have probably gleaned from its name, and its inclusion on this list — are two additional elements that are exclusive to the brand and historically used to denote a very special edition: one is the use of Honey Gold for the 41.5mm case; the other is the “Lumen” treatment of the dial and its various displays, in which the movement, the in-house-made Caliber L952.4, is visible behind a semi-transparent dial coated with a luminous compound — the same compound used in varying degrees of thickness on the hands, tachymeter-scale dial ring, date disks, moon-phase, and subdials. The darker the watch’s surroundings, the more radiant the ghostly green glow that it emits.

A. Lange & Söhne has stated that the Datograph Perpetual Tourbillon Honeygold Lumen, by far the most complicated timepiece yet to receive the Lumen treatment, "completes the series" at six models. (Speaking to the extreme rarity of all these models, It is also, as you might have surmised, the only watch in the series that our team has been able to get our hands on to shoot original photographs; kudos to our friends at Lange who granted us access to this very exclusive timepiece at Watches & Wonders Geneva 2024.) It's difficult to imagine that we'll never again see a Lumen version of another watch in the company's portfolio (an Odysseus version, perhaps?) but what form such a watch might take, and how it will be distinguished from the "Original Six" models, is a question for the future.