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Time, exceptionally composed.



What constitutes an exceptional composition? Whether in music, in art or in watchmaking: It is a work of art with many facets. It fascinates in every detail. And is unique in its totality. The delight of having a masterpiece enriches the senses because it repeatedly reveals new aspects that make the composition even more interesting.


The ZEITWERK HONEYGOLD “Lumen” is the fifth model in a series of timepieces endowed with semi-transparent dials and luminous displays. But this watch takes a step further as it unites two additional extraordinary features: The concept of a digital time indication with jumping numerals that is responsible for the inimitable design of the watch. And the remarkably warm gloss of honey gold, alloyed exclusively for A. Lange & Söhne. 

The ZEITWERK HONEYGOLD "Lumen" is an incomparable timepiece that features a luminous jumping numerals display and a case made of Lange-exclusive honey gold.

The ZEITWERK HONEYGOLD “Lumen” – revolutionary by day as well

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The ZEITWERK HONEYGOLD “Lumen” proves that A. Lange & Söhne’s product developers keep exploring new avenues. After all, this timepiece not only stands out with its inimitable design but also breaks through the limits of conventional watches with innovative mechanisms.


The ZEITWERK features a jumping numerals display with large, highly legible numerals that, as usual in a digital watch, read from left to right. The ingenious rotary mechanism consists of two discs for the minutes and a large hour ring that covers nearly the entire diameter of the movement.


Apart from the technical concept, the innovative design is revolutionary as well. The curved time bridge is one of the most prominent elements and provides an elegant frame for the time indication. In the ZEITWERK HONEYGOLD “Lumen”, it consists of black rhodiumed German silver that harmoniously complements the dark sapphire-crystal dial.


Inside, two mainspring barrels deliver the power needed for switching. The switching point is monitored by a patented constant-force escapement. It assures that the balance is always driven with constant power. The newly developed L043.9 manufacture calibre of the ZEITWERK HONEYGOLD “Lumen” has an exceptionally high power reserve of 72 hours. 


The pusher at 4 o'clock is new. It allows the hour indication to be separately switched, which simplifies the time-setting process. The switching impulse is triggered when the pusher is released, so switching is always uniform, regardless of how gently or vigorously the pusher is actuated.

Luminous numerals, clever idea


The ZEITWERK HONEYGOLD “Lumen” is a superior mechanical watch that reveals its second, fascinating face at night. In the darkness, only the numerals in the two display apertures will glow – nothing else. The technical challenge behind this development was to charge the numerals with light energy even though they are beneath the dial most of the time.

Anthony de Haas, Head of Product Development at A. Lange & Söhne, introduces the new ZEITWERK HONEYGOLD “Lumen”.

The solution: an elaborate special coating of the semi-transparent sapphire-crystal glass. 

It filters out certain spectra of visible light but lets most of the UV radiation pass through. This is exactly the range that charges the glowing pigments with light energy – to make them glow in the dark. The light permeability in the visible spectrum was reduced to the point where the disc mechanism is only vaguely recognisable during the day so that the clear legibility of the time is not compromised.


Thanks to the jumping numerals, the digital display remains readily legible after each switching cycle. Even at night. Because now, the numeral discs cause the watch to glow – whenever they become visible in the display after every full minute. The fascinating switching cycle is especially easy to observe at night.


The case of the ZEITWERK HONEYGOLD “Lumen” has a diameter of 41.9 millimetres and is crafted from Lange’s exclusive honey gold – a première for a “Lumen” model. This 18-carat gold alloy is especially hard and has an inimitably warm gloss. The hands of the power-reserve indicator and the subsidiary seconds as well as the prong buckle are made of honey gold too. Combined with the dark dial and the dark-brown leather strap, the hue is a real eye-catcher. 

Latest-generation movement 


Beneath the avant-garde dial with the prominent ZEITWERK bridge, 28 numerals on three discs can be faintly discerned. This is followed by a fascinating cycle that begins anew every minute.  

With a gentle click, at least one of the three numeral discs advances with a jump. It positions at least one new numeral in the display aperture – until, at the top of the hour, the ingenious mechanism simultaneously advances all three discs by one step.


The ZEITWERK HONEYGOLD “Lumen” has an hour correction pusher that makes the new manually wound calibre L043.9 much more complex, increasing the number of parts to 462 in comparison with the previous model. The setting of the minute display in both directions is performed with the crown at 2 o'clock.

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Many switching cycles can be observed through the sapphire-crystal caseback. For example, it reveals the hand-engraved balance and escape-wheel cocks, the winding wheels as well as the filigreed remontoir bridge that accommodates two screwed gold chatons.


The complex switching cycles are controlled by a patented constant-force escapement that handles two important functions at the same time: On the one hand, it generates the impulse for the jump of the time display. On the other, it drives the balance with nearly uniform power across the entire power-reserve period, which has a positive effect on rate stability.


The cam-poised balance with a freely oscillating balance spring beats with a frequency of 18,000 semi-oscillations per hour (2.5 Hz). Further Lange quality criteria include the exquisite finissage of the movement that is assembled twice. 

Discover the model

The “Lumen” models


The designation “Lumen” stands for a series of exceptional timepieces that with their semi-transparent dials deliver a strong design statement. The first one was the ZEITWERK “Luminous”, followed by the GRAND LANGE 1 “Lumen” and the GRAND LANGE 1 MOON PHASE “Lumen” in 2013 and 2016. The DATOGRAPH UP/DOWN “Lumen” was presented in 2018. All four models were introduced in limited editions and became coveted collectors’ items.









UP/DOWN “Lumen”







The technical challenge encountered in the development of the “Lumen” models was to charge even those luminous elements with light energy that were hidden beneath the dial. The patented solution is a semi-transparent sapphire-crystal dial with a special coating.


The transmission of light waves in the visible spectrum was reduced to obtain a high-contrast, easily legible dial. Conversely, the light waves in the ultraviolet range can pass through to charge the numerals with energy, allowing them to glow in the display apertures at night.

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