Bring A Flashlight: Glow-In-The-Dark Hands-On With The A. Lange & Söhne Datograph Lumen Up/Down

When we got the call informing us the new Lumen Up/Down was available for press preview, we jumped at the chance! Being a limited series of 200 meant the Lumen Up/Down wouldn’t be around for long. Even more impressive, the A. Lange & Söhne boutique informed Watchonista that ALL of the Lumen Up/Down have been spoken for. Being just a few weeks removed from the release, this is a rather impressive factoid indeed.
 

Once we had the watch in our hands, we began to understand the complexity required to produce this luminous marvel. What impressed me the most was the complex assembly necessary to give the transparent dial it's incredible depth. While the piece looks great under a UV light, seeing the Lumen Up/Down in ordinary light may be just as pleasing. Instead of the stark black dials found on previous Datograph models, the nearly full transparent sapphire crystal platters making up the dial provide an extraordinary depth to the piece.
 

You’ll hear us reference the Lumen Up/Down's dial quite a bit. After all, with very few exceptions, it's the dial, its various layers, and luminescent material which make the Lumen Up/Down what it is. The unique framed oversized date display you've come to know A. Lange & Söhne for is present in the Lumen Up/Down, yet unlike other models, a luminous material has been added to the full 31-day spectrum on the two date wheels. One notable point of intrigue which has echoed throughout coverage of this piece is that underneath the framed date, under almost all conditions, you can see portions of the other date wheels present and glowing under low light conditions. While some referenced that this could be a distraction to the readability of the piece, I don’t necessarily feel it’s an inconvenience.
 

The 41mm platinum case houses a manually wound A. Lange & Söhne caliber L951.7 viewable through the sapphire crystal case back. This proprietary flyback chronograph movement beats at 18,000vph and features a 60-hour power reserve which is represented on the dial at 6 o’clock. Remarkably, this ultra-precise movement out of Germany can start and stop on a dime. With the capability of controlling time up to the 1/5th of a second.
 

A. Lange & Söhne has chosen to “light” five separate indications on the Datograph Lumen Up/Down. The outer tachometer ring is the largest "lit" item on the watch, and once it's hit with a UV light or exposed to sunlight after an even a brief period, it glows quite remarkably. The two white sub dials indicating seconds (60 seconds) and minutes (30 markers). Just below 12 o'clock, you'll see the instantaneously switching date, brought to life via two luminous discs. Lastly, the power reserve indicator, positioned at 6 o'clock is a small arrow-shaped item which is applied with luminescent material. Throughout the piece, all luminous pieces glow a matching light green color. Which, once activated, lasts at full brightness for a few minutes and slowly fades. Over time, say an hour or more, the piece still retained some luminosity under pitch black environments.