While the finishing on any A. Lange & Söhne movement is certainly meticulous, it has slowly become a somewhat hackneyed pitch to oversimplify how the brand has, over the past twenty years, raised the benchmarks on classical watchmaking. Beyond the hand-engraved balance cock and double assembly, the maison is not short of resources and vision to develop and introduce novel ideas to the industry, as seen on the Triple Split (the only such complication on the market) and the Richard Lange Tourbillon Pour le Mérite (combination of two complications to increase rate of accuracy), impressing even the most discerning enthusiasts. The technical acumen has also extended beyond the movement, as exemplified by the Zeitwerk “Luminous”, which was introduced in 2010. And while luminous indications are seen in many timepieces, the Zeitwerk posed a particular challenge given that most of the digits used to display the time are usually hidden beneath the dial and the Zeitwerk’s signature time bridge, and therefore not exposed to the ambient light required to activate the luminous ink.
Lange solved the conundrum through the use of a tinted translucent dial, which allowed the ultraviolet light to charge the luminous digits while they were not displayed in the hour and minute windows. The result is a rather unique, tech-ish, luminescent dial that contributed to the watch, along with its limited edition run of 100 pieces only, earning the nickname of “Phantom”.
Fast forward to the end of 2021, the Zeitwerk Lumen (the “Luminous” moniker was changed for all subsequent luminous watches at Lange) is introduced once again, this time, in the brand’s proprietary Honeygold alloy that comes with an enchanting warm hue and extra structural integrity. The dial also shows some new alterations compared to the platinum version; they include the red markings near the empty side of the power reserve indicator, a slightly thinner printing overall, and the “Made in Germany” found near the six o’clock of the seconds register. Differences can also be found on the back of the watch including the size of the hallmarks and the “Glashütte in Saxonia” engraving.
This is considerably more though than an aesthetic update to the watch, as there are significant advancements within this second generation of the Zeitwerk calibre, L043.9, greatly pushing the boundaries of its technicalities. First of all, the calibre features a stacked double mainspring barrel that boosts the power reserve up to 72 hours from the original 36, which is only achievable considering the remontoir and the escapement are also tweaked accordingly to lower the overall energy extracted from the barrels. The remontoir spring is now thinner while the balance wheel is slightly lighter and smaller, reducing the consumption and resulting in a more energy-efficient movement.
Second, there is an extra button at four o’clock for advancing the hour, for which Lange ingeniously uses an inverse operating mechanism to prevent any damage from the excess amount of operating force, meaning the pusher doesn’t do anything when pushed in, instead, it triggers the function when the pusher bounces back out. Although the time can still be adjusted through the crown, this convenient feature certainly offers a less strenuous way for adjustment, especially when one travels across different time zones, a feature that becomes even more appreciated when one has to set the time on a previous iteration of the Zeitwerk family.
When comparing two generations of the Zeitwerk Luminous / Lumen calibres side by side, it becomes obvious that the calibre has undergone a degree of architectural changes, such as the winding gear train alignment, the Maltese Cross Stopwork that is no longer present on top of the barrel, and the remontoir bridge that is now straightened instead of the previous curved, anchor-like shape. These differences also appear among other later-generation Zeitwerk calibres, with the exception of the L043.5, whose architecture is further tailored to accommodate a minute repeating mechanism.
Another interesting bit to point out is that in the early generations of the Zeitwerk calibres, the minute display exhibited an arming motion around six seconds before the discs jump, whereby the minute disc would drop very slightly before the actual change. The maison’s watchmakers addressed this by preparing the arming mechanism to around thirty seconds instead of six, while also refining the tolerance of corresponding parts to eliminate these discernable movements before the actual jump.
The overview of Zeitwerk family thus far
Part of what makes the Zeitwerk collection so fascinating is perhaps the correlation between the digital time display and the constant force mechanism. Most of the remontoirs on wristwatches perform mainly as constant force mechanisms to mitigate the depreciation of torque as the mainspring unwinds, and are usually configured to accumulate and release energy from a shorter interval ranging from within a second to several seconds depending on the design. However, the remontoir in the Zeitwerk does not gradually build up the energy and release it to the escapement; instead, it is recharged instantly by the mainspring every minute, gradually releasing the energy to the escapement, and within that short amount of time, the remontoir also releases energy directly from the barrel to facilitate the instantaneous jump of the two stacked minute wheels and the hour wheel.
It has taken many years for A. Lange & Söhne to refine the Zeitwerk to this level, surmounting numerous technical challenges and yet never resting on its laurels, continually seeking to improve its functionality, even on levels that even the most astute collectors might never see. There is little question this Zeitwerk Honeygold Lumen edition is one of the maison’s proudest technical and aesthetic creations. Available exclusively through official boutiques, it is limited to only 200 pieces.