Reading time in the dark has always been a challenge, so find out how A Lange & Söhne sidesteps this problem with its Datograph Up/Down “Lumen”
What is the use of the most accurate and precise horological complication if you cannot read the information off the watch dial in pitch darkness? This is a conundrum faced by many watch brands, even the most storied ones. But it is no longer an issue with the A Lange & Söhne Datograph Up/Down “Lumen”, which made its world premiere in October.
Cleverly marketed by the German watchmaker as “the chronograph that never sleeps”, the latest member in the Lumen family indicates the time at any point of the day, even at night. All indications are legible even in darkness thanks to its semi-transparent dial and luminous displays.
The sapphire crystal is treated with a special coating that blocks out most of the visible light except ultraviolet (UV). This way, UV radiation can pass through the various elements on the dial including the outsize date, chronograph counters and tachymetric scale, which have all been applied with a luminous compound. These parts coated with the special chemical will glow in the dark with a green hue that has been scientifically proven to be pleasant for the human eye.
Of all the luminous parts, the outsize date is the most impressive. The date display is made up of two elements—a luminous tens cross and a black printed units glass disc, which rotates above a luminous background. Both are recharged during the day when they are underneath the semi-transparent dial. Because of this, even as the date changes at midnight, the outsize date remains luminous throughout and this entire sequence can be observed and appreciated in detail.
The Datograph Up/Down Lumen is clearly an aesthetic take on an old classic. For one, it doesn’t boast any technical upgrade with the watchmaker opting for the calibre L951.7, a variant of the manual-winding calibre L951.6 fitted in the 2012 Datograph Up/Down. It comes with 60 hours of power reserve and beats at a cadence of 2.5Hz.
(Related: Tracing A. Lange & Söhne's Fascinating History As A Watchmaker)
This is a case of not rocking the boat since the Datograph Up/Down already represents a major improvement over the manufacture’s first proprietary—and highly impressive—chronograph calibre. (Most marques, except storied watchmakers, don’t create their own chronograph because it makes more financial sense to procure and improve ready-made movements in the market than build from scratch.) The Datograph Up/Down can last about 60 hours when fully wound, up from the 36 hours of the original Datograph.
That said, the calibre L951.7 is more than just a piece of horological art. It is also a beauty to look at. Fully visible via the sapphire crystal caseback, every part of the in-house calibre is artistically and lavishly finished. The sharp polish on some components provides a counterbalance to the intricate engravings found on others. But these different delicate finishings only indicate the number of man‑hours needed to decorate the components, excluding the time taken to assemble the 454 parts of the watch.
