Tales of Lume Watches: Where it all Began
To the vast majority of watch collectors and enthusiasts, luminous material is a wonderful thing. On one hand immensely practical for telling time in less than ideal lighting conditions, and on the other nothing more than a cool hidden detail that adds an additional layer of visual complexity to timepiece design. Lume is yet another facet of watchmaking initially conceived solely for utility.
Effectively a byproduct of warfare, luminous indices and hands were first added to wristwatches in the early 1900s and by the time WWI was raging on, a “luminous wristwatch with unbreakable glass” was a part of the officer’s kit for the British military.
It was the discovery of radium, and its luminescent properties when mixed with zinc sulfide that triggered this boom, providing a solution for pilots and soldiers to tell the time without having to strike a match or use a flashlight. The challenge with this, as well as many new materials of the era, was that radium proved to be (you guessed it) radioactive, and though this was uncovered relatively quickly, it caused a fair bit of damage. For those of you who aren’t familiar, this is where the story of the “Radium Girls” came into play.
The US Radium Corporation hired numerous women to paint radium indices on dials, as many as 250 dials a day, and between 1917 and 1927 when a group of employees went after the company for compensation, several of these women were faced with severe medical complications tied to this radiation exposure. Needless to say, it was time for a new kind of luminous material. Though knowledge of its dangers were uncovered so long ago, its use was not banned until 1968, and its use continued in limited volume until that time.
Thankfully, the fact that tritium has the same properties as radium (though being far less radioactive to the point of being dubbed “safe”) meant a new material was easily able to pick up where radium left off. Considering its glow stems from material decay, tritium does have a shelf life which has proven less than ideal, but as many vintage watches have proven you’re looking at a matter of decades rather than just a handful of years. Interestingly, the use of tritium has evolved in modern watchmaking, and though it isn’t as popular as it once was it still sees relatively frequent use.
What’s different though, is its application. Traditional luminous tritium was created as a paste/paint the same way that radium was. At present day, mentions of tritium in watchmaking are often in reference to tritium gas tubes; thin glass cylinders filled with a gaseous form of the material providing the required luminescent glow. Alongside this evolution, many brands (Ball Watches especially) have figured out how to alter the glowing color of tritium gas, leading to very unique dial configurations with different lume color for different indications.
Stepping away from radioactivity, photoluminescent compounds became the new alternative for adding luminous indices and hands to watches. On the plus side, these materials (Super-LumiNova, Rolex’s Chromalight, and Seiko’s LumiBrite) are even safer to work with than tritium on account of not being radioactive at all, though they have their own quirks from a functional standpoint. Unlike their glowing brethren, these materials glow by capturing and re-emitting light. This means that without exposure to light, your watch will not have any luminous output. Further to this, after between 12 and 24 hours of darkness its glow will slowly fade to darkness.
Recently there have been a handful of spectacular releases that use luminous material exceptionally well. The A. Lange & Söhne Lumen series, in particular the Lange 1 Moonphase Lumen, is a prime example, with this particular model featuring a luminous double date and moonphase indications. Stepping into the realm of independent watchmaking, both MB&F and Sarpaneva have integrated hefty doses of lume into their designs, both working with James Thompson of Black Badger Advanced Composites who has been working with other unique photoluminescent materials over the years. No matter if your tastes run conventional or outlandish, you’ll be able to find ample options to satisfy your glowing desires.
