The Datograph Up/Down “Lumen” is the fourth model in the “Lumen” series launched by A. Lange & Söhne. Its harmoniously balanced dial with the characteristic outsize date strikes the eye at first sight. The luminous display makes it possible to use all chronograph functions even in darkness.
For quite some years, the Datograph Up/Down has been the benchmark in chronographs. Its assets include the outsize date, the useful flyback switching mechanism for the chronograph and a patented, precisely-jumping minute counter. The precisely jumping minutes display of the chronograph function at the 4 o’clock position and the subsidiary seconds display at the 8 o’clock position are finished with concentric circles, the azurage technique.
The “Lumen” version of the DATOGRAPH UP/DOWN makes it possible to use all chronograph functions even in darkness.
The Datograph Up/Down “Lumen” reflects the passion of A. Lange & Söhne for developing innovative chronographs. During the day, the luminous display is charged with light energy through the semi-transparent dial and makes it possible to use all chronograph functions in any circumstances. The sapphire-crystal back of the Datograph Up/Down “Lumen” reveals the L951.7 calibre manufactured of 454 lavishly finished parts. The Datograph Up/Down “Lumen” is equipped with a precisely jumping minute counter which advances by one graduation exactly after 60 seconds have elapsed, even if the time measurement is stopped at that very moment.
The patented special coating of the dial filters out most of the visible light, but not the part of the UV spectrum that is needed to charge the luminous pigments with enough light energy to keep them glowing in the dark.
The outsize date of the DATOGRAPH UP/DOWN “Lumen” is composed of two separate noctilucent elements – a luminous tens cross and a black printed units disc made of transparent glass which rotates above a luminous background. The semi-transparent dial allows the tens cross and the luminous background to recharge during the day. As a result, the outsize date glows in the dark, even immediately after switching at midnight.