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A. Lange & Söhne Grand Lange 1 Lumen

by Philip Kaspar
18 December, 2012
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Philip is widely travelled and has worked as a freelance journalist covering several topics including fashion, travel and watches. He also spent five years in the heart of the Swiss watchmaking industry in La Chaux de Fonds. Philip reports on all the latest watch news and is our WatchCrime reporter.

A. Lange & Sohne Grand lange Lumen close up

The new Grand Lange 1 from Saxony manufacture A. Lange & Söhne is called the Grand Lange 1 Lumen. And it actually sheds light on a secret of how the lsuperb legibility of the piece is achieved.

Parts of the dial of this magnificent limited edition watch consist of semi-transparent sapphire crystal. Only the outer ring and the surfaces of the displays for hours and minutes as well as small seconds are made of blackened silver.

The sapphire crystal surfaces reveal the disc mechanism of what is the first outsize date that glows in the dark. Additionally, the time and the power reserve are also legible in the dark.

The Lange outsize date was originally inspired by the Five-Minute Clock in Dresden’s Semper Opera House to which Ferdinand A. Lange contributed his expertise in 1841.

Just like its well know role model, the date mechanism uses two separate display elements. The ring-shaped units disc with the numerals 0 to 9 switches once a day. But at the transition from the 31st to the 1st day, it stands still for a day. The tens cross with the numerals 1 to 3 and a white blank space advances by one increment only every ten days. When it displays the 3, the tens cross advances to the blank space after only 2 days. The irregular switching sequence is controlled by two programme wheels with a precisely calculated toothing pattern.

A. Lange & Sohne Grand Lange Lumen

The technical challenge for the Grand Lange 1 “Lumen” was to ensure maximum luminosity for the date display, even immediately after the daily switching operation. Lange’s designers solved this issue by ensuring that as the tens cross they are coated with a white luminous compound and subsequently imprinted with black numerals, the units disc consists of transparent glass imprinted with black numerals and rotates before a luminous background.

The sapphire crystal sections of the dial are treated with a special coating that blocks most of the visible spectrum of light. For the invisible UV light spectrum, however, the coating does not represent a barrier. Therefore, UV radiation can pass through to the luminous surfaces of the outsize date unhindered. This produces an interesting side effect: the date platform with its manually applied perlage, normally seen only by the watchmaker during the assembly process, is now visible to the owner as well. The small, overlapping circular graining produced by hand using a rotating abrasive peg is normally concealed underneath the dial.

A. Lange & Sohne Grand Lange Lumen movement

Last year, A. Lange & Söhne endowed the Grand Lange 1 with a totally new, manually wound calibre. The omission of the second mainspring barrel as well as the effective arrangement of the parts have reduced overall height of the calibre without any compromise in terms of power reserve, making it possible to transpose the graceful dial architecture of the Lange 1 to the enlarged model. The dial of the Grand Lange 1 “Lumen” presents the indications of the hours, minutes, seconds, outsize date, and power reserve without any overlaps.

Philip Kaspar | Website

Philip is widely travelled and has worked as a freelance journalist covering several topics including fashion, travel and watches. He also spent five years in the heart of the Swiss watchmaking industry in La Chaux de Fonds. Philip reports on all the latest watch news and is our WatchCrime reporter.

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