With the new Datograph Up/Down "Lumen", there will be no more late-night scrambling in the dark for the power switch to turn on the light just to find out what time it is. “Lumen” is the name of an A. Lange & Sohne series in which the watches are treated with a luminous compound on the sub-dials, the chronograph sweep seconds hand, the circumferential dial ring with minute scale, the tachymeter scale and the power reserve arrow. What this means is that every key indications of the watch light up in the dark, an unusual but useful touch.
Also see: When A. Lange & Sohne celebrated its 200th anniversary
The Datograph’s most striking feature, the outsized date apertures at ‘12’, also gets the glowing treatment thanks to a disc that rotates above a luminous background. Thanks to an ingenious work of chemistry, this luminous background is actually recharged with UV light travelling through the transparent sapphire dial.
During the day, this dial endows the watch with a unique appearance where the date disc and the movement’s perlage-decorated baseplate are visible. At night, or in the dark, the entire watch takes on an eerie green glow. Additionally, the date apertures play up this effect by glowing at midnight, the moment when the date switches.
