An Outsize Date Floating in Green, Born from Idea and Ingenuity

The "Datograph Up/Down "Lumen" is the fourth model in A. Lange & Söhne's "Lumen" series, first unveiled in 2010. In addition to a semi-transparent sapphire crystal dial, luminous pigment is applied to all displays, ensuring clear legibility day or night.

The sapphire crystal dial features a special coating that blocks most visible light while allowing the ultraviolet rays necessary for the luminous pigment to store light. Luminous pigment is applied to all displays, including the hour and minute hands, chronograph seconds hand, the two sub-dials of the Outsize Date, the minute track on the outer circumference of the dial, and the power reserve indicator. As the surroundings darken, the characteristic green glow permeates the semi-transparent dial, vividly highlighting the displays.

The chronograph displays are also striking. The flyback mechanism allows for continuous timing by simply pressing the pusher at 4 o'clock once to interrupt the measurement, reset it, and immediately start the next timing. While a standard chronograph requires three steps—stop, reset, and restart—the flyback mechanism enables speedy and precise continuous timing with a single operation.

Of course, the most distinctive feature is the luminous Outsize Date. This date display, with its two windows for the tens and units digits, glows even at the moment the date changes at midnight. The secret lies in a cross-shaped plate for the tens digit coated with luminous pigment and a glass disc for the units digit. The plate, which stores daylight, glows as darkness falls, allowing a view through the semi-transparent dial of the Outsize Date mechanism's movement and the transition of the date display.

The sapphire crystal case back offers a view of the beautifully decorated hand-wound Caliber L951.7. This new model, with a 41 mm platinum case, black alligator strap, and platinum pin buckle, is limited to 200 pieces worldwide.