Teddy Baldassarre
Tritium Watches: How They Work, And How They're Still Being Made
The need to read the time in the dark has been a challenge for the makers of timepieces for hundreds of years. The first solution was not a visual but an audible one: watches that could chime the current hour and minute on demand. These types of watches, aka minute repeaters and sonneries, are quite rare and expensive today and regarded as luxuries rather than the utilitarian inventions they initially were. In the 1900s, a more practical option presented itself: treating a watch’s dial with luminous paint that made its time display visible in darkness. And while this approach proved to be much more cost-effective and practical, it also brought a new set of challenges, as the earliest substances used on the dials were discovered to be unsafe, for the people who made the watches and, to a lesser extent, those who wore them. Let There Be Light The first material applied to watch dials for nighttime luminescence was radium paint, which, thanks to radium’s half-life of 1,600 years, offered a long-lasting glow during that period before dimming - the catch being that, as its name implies, radium (specifically Radium-226, which was used as the base of the “Radiomir” substance registered by Guido Panerai ) is radioactive. In the 1920s, the mostly female factory workers who painted the watch dials with radium compounds started falling ill and dying at alarming rates, leading to lawsuits against the companies that produced the material and eventually, safer working conditio...
