A Lange & Söhne’s latest Datograph model reliably tells the time around the clock, and its stop function can be used at any time as well. Indications are legible even in darkness,all thanks to its semi-transparent dial and luminous displays.
The chronograph with a flyback function has a precisely jumping minute counter and a power-reserve indicator all of which come in a limited edition of 200 watches.
The round the clock display, which glows in the darkness with a distinctive green hue that the human eye perceives as soothing, is achieved by the hour and minute hands being filled with luminous material; the chronograph sweep seconds hand is fully coated with the compound. The second’s hand and minute counter in blued steel revolve above subsidiary dials that are luminous too. The circumferential dial ring with the minute scale that is subdivided into fifth-of-a-second graduations, the concentric tachometer scale and the power-reserve arrow applique also glow in green.
Then there’s the luminous outsize date. Composed of two separate display elements, the outsize date is designed to glow immediately after the midnight switching sequence as well. This is made possible with a luminous lens cross and a black printed units disc made of transparent glass which rotates above a luminous background.
The Datograph UP/DOWN “Lumen” is the fourth model of the “Lumen” series that A. Lange & Söhne originally launched in 2010. A special coating on the semi-transparent sapphire crystal dial filters out most of the visible light, but not that part of the UV spectrum which is needed to charge the luminous pigments with light energy. The darker the surroundings, the more clearly the displays contrast against the dark background.
The Datograph UP/DOWN also indicates how much of the 60-hour power reserve remains available. This information is provided by the power-reserve indicator at 6 o’clock. When the small arrow enters the red zone of the display, it is time to provide the movement with fresh energy.
The sapphire-crystal caseback exposes the impressive beauty of the lavishly finished 454-part manually wound calibre L951.7 of the Datograph UP/DOWN “Lumen”. Lange’s proprietary cam-poised balance wheel, paired with a freely oscillating Lange hairspring, beats at a frequency of 18,000 semi-oscillations per hour (2.5 hertz). In combination with the 300-marker minute scale, this allows time measurements with a resolution of one-fifth of a second. The new model, available in a limited edition of just 200 watches, comes in a 41-mm platinum case. It’s worn on a black alligator leather strap with a platinum prong buckle.
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