A. Lange & Söhne: Lumen “NORTHERN LIGHTS”

The interplay of opposites culminates in perfection with the northern lights in the Arctic sky above Iceland. For A. Lange & Söhne’s three luminous models, this is the ideal setting to showcase the spectacular contrast between light and darkness. The trio of fascinating light virtuosos that accompanied the Nordic expedition earlier this year included the Grand Lange 1 Moon Phase “Lumen”, the Zeitwerk “Luminous” and the Grand Lange 1 “Lumen”, it is the third A. Lange & Söhne model with a semi-transparent sapphire-crystal dial. Its light-permeable coating allows the numerals to absorb a sufficient amount of light energy to uniformly glow in the dark for several hours.

Watches with luminous displays need a light source that charges the luminous compound applied to the display elements and allows them to glow. Thanks to the semi-transparent black-tinted dial and an ingenious mechanism, the “Lumen” displays can be permanently charged with light energy.

The dial of the Grand Lange 1 Moon Phase “Lumen” is made of blackened silver with generous apertures and a semi-transparent black-tinted sapphire-crystal glass wafer. The special coating applied to the glass blocks most of the visible light but not the UV spectra that “charge” the luminous pigments on the outsize date mechanism and cause them to glow in the dark. The tens cross is coated with a white luminous compound and printed with black numerals. Conversely, the units disc, also featuring black numerals, is made of transparent glass and rotates in front of the luminous background of the date aperture.

The lunar disc is made of glass. First, the glass surface is coated with a patented process. Then 1164 stars and the moon are cut out with a laser beam. The luminous compound behind the lunar disc makes the moon and the stars shine. The large moon-phase display occupies a prominent position on the main dial. Once properly set, it only needs to be corrected by one day every 122.6 years.