A. Lange & Söhne

THE LANGE MOON PHASE MOONDISC Recently I discovered how these wonderful moondiscs are made but this process has been around since ~2005 at Lange. If you hold up to the light a Langematic perpetual up close and gazed intently at the moonphase. There is cla...  

so the "blue" carbon layer is removed with a laser; but looking at the first picture you posted: it seems to me that the two moons present on the disc are 3D in appearance and not "flat" ... does the laser not only remove the carbon but also a little bit ...  

but i presume that the process begins with not applying the "blue" ta-C layer to where the moon positions are to start with. the moons are concave and polished and they probably leave this alone from the start. the process can be controlled very accuratel... 

so they start with the gold disc where the concave (arent they convex?) moon(s) already present? and how do we discriminate the old moonphase discs from the new? Edwin

of which the answer i know not of

In order to get blue....we have to remove orange light...so the thinness of the transparent carbon coating should be 590/4=150nm or multiply of 150nm I think.......you may able to distinguish this kind of surface by look at it with putting different angle...  

light waves reflected at the gold substrate and light waves reflected at the "blue" carbon will cancel out each other - the color at which this happens is depending on the thickness of the carbon deposited on the gold disc Thanks E

It is what happen on camera len as well, so you can captured you lange well...^_^ This message has been edited by Ogygia on 2009-06-25 10:19:50

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Light reflect from metal can't be polarized light....but the carbon coating can. With certain angle...the color of this coating metal with change to its own color with a polarizer.... let me test my fd's lange later...

When the platinum Langematik Perpetual was introduced, it had a very dull, dark blue moonphase disc. It was my only complaint about that watch. A few years later, Lange change the blue color to the current, lighter, more vibrant blue. About a year or two ... 

Much appreciated! Stephen

This reminds me of the vacuum deposition process to put down the nanometer thick metal oxide layers for AR coatings on crystals. Bill

very informative Cheers

nt

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Looks like a complex process with plenty of room for error, defects, and rejections that complicate the process.

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