Compare that to radium, which on average lasts about 1,600 years.įortunately, watchmakers only used promethium for a short amount of time. It’s an extremely strong and rare earth metal with a half-life of two and a half years. Promethium is significantly less radioactive than radium. Unfortunately, the substance introduced as an alternative was also radioactive. Once scientists discovered how toxic radium paint is, it quickly fell out of use in the watchmaking industry. Promethium (pm-147) Is Briefly Used as a Substitute However, the material was still common in watch dials until 1968, when lawmakers banned it. Radium’s dangers came to light in the 1920s, when the “ Radium Girls” filed a lawsuit. Even a bit of radium paint worn on a watch can impact overall health. Prolonged exposure to radium can lead to cancer in the blood, the eyes, the bones, or anywhere else in the body. The problem with radium paint is the same problem with radium-it’s radioactive, which means it’s highly toxic for human beings.

With the invention of radium in 1908, watchmakers saw an opportunity with radium and used it to paint on the hands and hour markers of watches in the early 20th century. You can then apply the paint to anything-paper, hard surfaces, or the side of caves. When mixed with a phosphor and a clear varnish, it acts as a binder to make paint. Radium breaks down into a fine powder, called radium salt. Pioneering chemist Marie Curie discovered it at the turn of the 19th into the 20th century, and it now takes up a spot on the periodic table of elements. Radium is a radioactive metal that emits a natural, luminescent glow. The first attempt to introduce luminescence to watchmaking was radium paint. So, people got to innovating… Radium Paint Is Invented There needed to be a way to tell time on the go, even in dimly lit circumstances. Street lighting wasn’t as common as it is now, and it’s not as if people had flashlights in their pockets as we all do now with smartphones. Luminescence was a natural development in this history. When the public saw how helpful the watch was, people started buying them in large quantities. Before then, they were a highly gendered accoutrement, with women wearing wristwatches.Īll that changed with World War I, when soldiers, divers, and laborers needed an easy way to tell time while doing their various duties. Though the technology was there to make wristwatches as early as the late 19th century, wristwatches only became ubiquitous by the end of World War II. It goes back almost as far as the history of the wristwatch itself. But the truth is that luminescent technology in watches isn’t a recent phenomenon. The lume used in modern watches looks futuristic-think incandescent greens, yellows, and even pinks and purples that radiate a soft glow visible to the naked eye from far away. The History of Luminescence in Watchmaking Keep reading to uncover the secret behind watchmaking’s most dazzling aesthetic touch. Here, we take a deep dive into the history of luminescence. Some of them were toxic, and some simply impractical. Watchmakers have used various processes to achieve lume. Lume can provide the wearer with a much-needed light when they try and read the time at night. Lume is helpful in wristwatch construction, not just for aesthetic reasons. Luminescence, or lume, has been used in watchmaking for over a century. The secret to so many of these tantalizing marvels is luminescence. Fortunately, this is not necessary in a DC-powered device like LUMEBOX®, which does not require wall sockets, unlike larger AC-powered panels.Human beings have always had a fascination for bright lights in the dark-fireflies, lightning, some jellyfish, and other deep-sea creatures. Instead, waveform and flicker index are better measures to consider when measuring flicker rate. You’ll see companies claim they are ‘low flicker’ but this can be misleading terminology because lower flicker rates (below 60Hz) are still detectable to the naked eye. In hyper-sensitive individuals, flickering in lighting may be associated with headaches at the workplace when exposed to long periods, particularly at lower flicker rates of less than 120hz.

While mild flickering may occur for 1-2 seconds when switching between modes, this is expected as the power switches between electrical circuits and should not have any health effects, unless the user is hypersensitive. Since LUMEBOX® is powered by DC power (battery), flicker is not considered an issue. Flicker is primarily caused by the stability level of the power supply, which is a greater concern for LED products that operate on AC power.

Lume light