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A. Lange & Söhne

Ok, so its the Datograph up&down LUMEN...

 

Its semitransparent dial allows charging of luminous indices and complete visibility during night.







This is technically more advanced than it first appears, as the luminous material is hidden beneath dial elements. Here an expert from the press info:

"The “Lumen” version of the DATOGRAPH UP/DOWN makes it possible to use all chronograph functions even in darkness. Furthermore, the time indication, the power reserve and even the date are noctilucent. The technical challenge behind this development was to charge the numerals of the outsize date with light energy even though some of them are concealed beneath the dial for the better part of the day.

The solution is a patented special coating on the semitransparent sapphire-crystal dial. It filters out most of the visible light, but not that part of the UV spectrum which is needed to charge the luminous pigments with enough light energy to keep them glowing uniformly in the dark. The transmission of light in the visible spectrum is attenuated to such a degree that, during the day, the sophisticated disc mechanism and the exquisite finishes are clearly exposed while ensuring good readability.



Composed of two separate display elements, the outsize date glows immediately after the date change at midnight as well. This is made possible with a luminous tens cross and a black printed units disc made of transparent glass which rotates above a luminous background. The fascinating midnight switching sequence can be observed in detail."

Crafted in platinum and limited to 200 pieces.
Magnus

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