The new GRAND LANGE 1 “Lumen” watch comes with a semi-transparent dial that exposes the ingenious mechanism of the first luminescent outsize date display by A. Lange & Söhne. Equipped with the manual-winding L095.2 calibre, this platinum watch comes in a limited edition of 200 pieces.
Parts of its dial 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 the first outsize date that glows in the dark. Additionally, the time and the power reserve are also legible in the dark.
The technical challenge encountered during the development of the GRAND LANGE 1 “Lumen” was to ensure maximum luminosity for the date display, even immediately after the daily switching operation.
Lange’s product developers solved this issue in an exceptional way. While the tens cross was 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.
Beating inside the watch, the hand-wound Lange L095.2 manufacture movement can be admired from the other side through the sapphire-crystal caseback. The omission of the second mainspring barrel as well as the effective arrangement of the parts reduced the overall height of the calibre without any compromise in terms of power reserve.
The dial of the GRAND LANGE 1 “Lumen” presents the indications of the hours, minutes, seconds, outsize date, and power reserve without any overlaps.
Model: A. Lange & Söhne GRAND LANGE 1 “Lumen” Limited Edition in Platinum
Lange manufacture calibre L095.2, manually wound, crafted to the most exacting Lange quality standards, decorated and assembled by hand; precision-adjusted in five positions; plates and bridges made of untreated German silver; balance cock engraved by hand
Movement parts: 400
Screwed gold chatons: 7
Escapement: Lever escapement
Oscillator: Shock-resistant screw balance; superior-quality balance spring manufactured in-house, frequency 21,600 semi-oscillations per hour, precision beat adjustment system with lateral setscrew and whiplash spring
Power reserve: 72 hours when fully wound
Movement dimensions: Diameter: 34.1mm; height: 4.7mm
Crown for winding the watch and setting the time; push piece for rapid correction of the outsize date
Time indicated in hours, minutes, and subsidiary seconds with stop seconds
Case dimensions: Diameter: 40.9 millimetres; height: 9.8 millimetres
Crystal and back: Sapphire crystal (hardness 9)
Basic dial (outer ring, hour, minutes, small seconds) of solid silver (black), recessed parts of sapphire crystal with semi-transparent coating; luminous outsize date and indications for hours and power-reserve
Hands: Rhodiumed gold; hours, minutes, power-reserve indicator luminous
Hand-stitched crocodile strap, black
Buckle: Lange prong buckle in platinum
Limited edition of 200 watches
Image Credit: Lange Uhren GmbH