Watches with strong luminosity

Even the most precise, reliable clock is of little use if you can't read it. If darkness prevails, many watches thus lose their usefulness. It's different with models that glow in the dark. These special timepieces, which are used in the field of diving watches and military watches, for example, defy adverse lighting conditions and have been shaking up the watch world for quite some time. This article is dedicated to wristwatches with luminous material, compares the different illuminants and presents selected ladies' and men's watches with luminous numerals and dials.

What does "strong luminosity" mean?

For use in watches, luminescent substances that have a certain luminosity without having to be strongly heated for this purpose are of particular interest. With sufficient heat, many materials begin to glow, but this heat cannot be generated in the everyday use of a watch. Just imagine if you had to take your everyday watch off at regular intervals to warm it up - that is simply not practical. In addition, in this case, all of the materials processed would have to withstand the required heat. This would undoubtedly seriously limit the choice of materials.

In order for watches to glow in the dark, a luminescent material is required that has a so-called cold light emission and thus emits light without requiring strong heat. This is called luminescence.

To put it simply, luminescence is triggered by suitable means through the activation of atoms or molecules with the aid of chemical, mechanical or electrical processes. In the course of these processes, energy is generated, which is subsequently emitted in the form of light - the watch acquires luminosity. The strength of the luminosity is typically defined according to the brightness of the light or the luminous period per individual process.

Types of luminous materials

The watch industry is now familiar with a wide variety of different materials and luminous colors that can give hands, indexes and dials a leg up when it comes to light. We'll take a closer look at the most common, most widely used, and most storied luminous materials for watches below:

Radium

What may seem strange from today's perspective was a breakthrough for the Italian watch brand Panerai: radium watches. In 1914, the founder of the traditional company, Guido Panerai, patented the luminous substance Radiomir, which was based on radium bromide and, in combination with zinc sulfide, produced a permanent, heat-independent glow. Such luminous materials could thus keep watches lit for long periods of time - in fact, measured by the half-life of radium, over 1,600 years - without the need for recharging in between.

Some readers may wonder how dangerous it is to wear radium watches. After all, radium is generally known for its radioactivity. The answer is accordingly quite surprising: Radium incorporated into a watch as a luminescent material is almost harmless to the wearer. But how can this be? Quite simply, the radiation from the radium luminescent material in the Radiomir watches was largely intercepted by the case and thus had only a negligible effect on the wearer.

However, the buyers of the watches did not even have to be convinced of this fact, because there was little skepticism towards the material among the population at that time anyway. On the contrary, radium was even advertised as healthy and used in a wide variety of foodstuffs, care products and medicines. There were - even if this is hardly imaginable from today's point of view - radium drinking cures, chocolate with radium additive and radium-containing toothpaste. If one consumed radium - or wore it on the wrist - one did not worry at all, but rather had the feeling that one was doing something good for oneself. It was not until much later that radioactivity became associated with all sorts of health hazards.

The catch: the watches had to be produced somehow, the workers inevitably came into contact with the radium, and the radioactivity by no means passed them by without leaving a trace. So, as harmless as they were to the wearers, they were equally harmful to those involved in the manufacturing process. The keyword here is "radium girls." This was the name given to the female workers who handled the luminous material on the opened watches and absorbed any amount of radium. Several of the Radium Girls subsequently had to fight severe cancer - how many deaths radium clocks caused in total is not documented.

Tritium and tritium gas

As knowledge of the significant disadvantages of radium progressed, there was an increasing urgency to find an alternative. In the 1960s, tritium, a hydrogen isotope with a twelve-year half-life, was finally brought into use. However, this did not solve the problem of radioactive radiation, because tritium is also radioactive, although less so than radium. The use of tritium was therefore a step forward, but it soon became clear that a final, sustainable solution had not yet been found.

As a result of the further development of tritium luminous material, tritium gas, GLS Tritium H3, was integrated into watches a little later. The gas was filled into glass tubes coated with phosphorus, which was supposed to minimize radiation, and for the first time allowed the creation of color effects on the resulting light. The tritium tubes were used as hands and indices in H3 watches and served their purpose: they made it easier for the eye to read the watch despite darkness and poor lighting conditions.

By the way, nowadays tritium H3 watches are marked T, T25 and H3, which are usually found on the dial. Timepieces with tritium as luminous material are no longer produced since the 90s.

LumiNova

With the development of the luminescent material LumiNova by the Japanese company Nemoto, a new era in the field of watches with luminosity was ushered in. For the first time, it was now possible to make watches glow without radioactive side effects - a huge milestone. Instead, this material, which consists of alkaline earth siluminates, is charged by external light - whether artificial light or daylight - and the luminosity is measured by the intensity of the charge. LumiNova is therefore a so-called afterglow ink that can be used to produce light in a wide variety of colors.

Super-LumiNova

Meanwhile, the substance that makes watches glow is called Superluminova C3, Chromalight or even LumiBrite. Which designation you find depends mainly on which manufacturer you look at. In essence, it is always one and the same product, albeit in slightly different variants. The background: Both the Swiss company RC Tritec and the watch brand Seiko had the opportunity in the 90s almost in parallel to purchase the luminescent material from Nemoto and to market it under different names.

While LumiNova has a maximum luminous period of five hours, watches with Super-LumiNova shine for up to 15 hours before their brightness and luminosity slowly but surely diminish and a recharge becomes necessary. As a versatile luminous material, Super-LumiNova, Chromalight and LumiBrite, respectively, can be used, for example, as a luminous color in green, orange or blue, with the blue luminous material being particularly popular for diving watches.

How exactly Super-LumiNova watches present themselves in the dark varies from brand to brand and from product to product. In the meantime, there are watches whose entire dial is illuminated by the luminescent material, bracelets framed with light, luminescent logos and, of course, the classic luminescent hands and indices. Often, watch brands succeed wonderfully in seamlessly integrating the Superluminova coating into the design and creating an optimal overall image.

Advantages and disadvantages of different luminous materials

To conclude the overview of the common luminous materials for watches of the past decades, we dare to compare and discuss the concrete advantages and disadvantages of the individual luminous colors very briefly.

The disadvantages of radium and tritium are obvious. The luminous materials were dangerous due to their radioactivity, especially for the workers who had to openly handle the materials. Although tritium is less radioactive than radium, it loses its luminosity after only twelve years and must still be considered a potential health hazard. Nevertheless, one major advantage of the two luminescent materials that were popular in the past should not be swept under the carpet: They managed entirely without an external energy source and did not need to be rhythmically recharged. However, this plus point cannot, of course, make up for the health risks and problems associated with the manufacture, maintenance and disposal of tritium and radium clocks. It is hardly surprising, then, that such items are no longer produced today.

Compared to this, tritium gas can be described as harmless and is therefore more suitable for use in watches. This luminous color also glows continuously. Thus, no external energy source is needed to make the watch glow with tritium gas. The drawback: tritium gas is bound to the half-life of tritium, which is why the light fades after about twelve years.

Which brings us to LumiNova and Super-LumiNova. Both luminous colors have the huge advantage of being harmless to health, are not radioactive and can therefore be used with much less risk. However, LumiNova and Super-LumiNova - unlike tritium, for example - rely on external light sources to function as luminescent materials. They need to be charged by light irradiation in order to do their job, and they need to be charged regularly. The difference between the two products is mainly related to luminous duration and phosphor colors. LumiNova can be seen glowing in the dark at full intensity for a maximum of five hours, while Super-LumiNova lasts a full 15 hours. In addition, Superluminova is available in significantly more color variants, so that the visual design possibilities of the dial, indices, hands and so on are multiplied.

The best watches with strong luminosity

Whether with LumiBrite, Superluminova, Chromalight or a similar non-hazardous luminous material, many manufacturers carry watches that glow in the dark, making them suitable for outdoor adventures in the dark. Six of the most popular products of this type are presented below:

Omega Seamaster 300M

A watch that immediately catches the eye and delights collectors around the world: the Omega Seamaster Diver 300M. Water resistant to a depth of 300 meters, this watch impresses with its sporty design and excellent functionality. Since the first Seamaster was launched in 1993, the watches have almost consistently been among the most sought-after models of their kind. This is probably not least due to the fact that the Seamaster scores with excellent readability in the dark. This is an indispensable extra, especially for divers, for whom the watch was originally designed.

To ensure this, Omega equips the watches with Super-LumiNova. The luminous material makes hands and, if necessary, beads on the dial glow in the colors green and blue in the dark. The dial itself has the wave pattern, which is considered a typical feature of the Seamaster and gives the timepieces their own unique charm. From the manufacturer, the Seamaster 300M with Superluminova can be purchased with either a metal bracelet, NATO strap or bracelet made of sturdy rubber.

Rolex Submariner

The Rolex Submariner is the epitome of a modern, highly functional diver's watch. The manufacturer promises optimal readability of the watch, even in the depths of the underwater world, and uses the Chromalight material for this purpose. The luminous color is characteristically blue and convinces with a luminous period of up to eight hours. The luminous material is not only applied to the hands and indices, but also decorates the chaton on the bezel.

And even aside from the Chromalight color, the Submariner definitely has a lot to offer. It is water resistant up to 30 bar, and thanks to 60-second engraving on the bezel, it helps to read the dive time precisely. Among the materials used in the manufacture of this first-class watch is Cerachrom, which is particularly scratch-resistant and resistant to chlorine and salt water.

Panerai PAM 632

After talking about the renowned Italian watch brand Panerai several times in this article, we will now take a look at a particularly popular model of the manufacturer. The PAM 632 is a men's watch with manual winding, which dares a balancing act between down-to-earth classicism and modern sportiness in terms of design.

The watch from the Luminor Marina collection shines with an 8-day power reserve, a deep brown dial and a solid case made of durable stainless steel. The processed luminous material, thanks to which you can perfectly read the watch with reference PAM 632 even at night, is - unsurprisingly - Luminor. This is located on the indices, hands and numbers on the dial.

Breitling Navitimer

A coveted pilot's watch, the Breitling Navitimer is a collector's item that has delighted the watch world for about 65 years. Breitling's watches are now available in quite a few different styles - sometimes sportier, sometimes classically elegant. However, the models have one thing in common: the integrated luminous material gives them optimal readability.

Today, Breitling uses the luminous paint Superluminova, which can be found in the Navitimer timepieces both on the indices and on the hands for minute and hour. In use, a Navitimer watch should be able to score with a consistent luminous period of at least eight hours, as confirmed by the experience of wearers. Connoisseurs overwhelmingly agree that among Super-LumiNova watches, Breitling Navitimer is one of the best.

Nomos Glashütte Autobahn

If there is a modern watch that can be considered the embodiment of passion for high speeds and pure movement, then it is probably the Chronograph Autobahn on Nomos Glashütte. The domed dial, the three-track date window and the precise neomatik movement are just single examples of outstanding details that distinguish this watch. What appears at first glance to be straightforward and simple, harbors an undreamed-of complexity and a variety of functions that one has come to expect from Nomos Glashütte over the years.

Made for frequent drivers and those who can often be found on the roads at night, the Autobahn watch naturally glows in the dark. Nomos Glashütte uses Superluminova for this effect, using the luminous paint quite liberally. The dials of the watches are provided with a comparatively wide luminous ring in blue color, briefly interrupted in each 5-minute cycle - so the dials are illuminated almost in their entirety and can be read comfortably. Complementing the highly illuminated dials, the hands are also coated with Super-LumiNova, making the overall look extremely cohesive in both daylight and darkness.

Maurice Lacroix AIKON Venturer

The last watch with luminous colors that we are going to focus on in this article is the AIKON Venturer by Maurice Lacroix. Intended, in a way, as a tribute to the Lacroix Calypso range of the 90s, the AIKON Venturer collection amazes with unspeakable diversity. It includes a variety of diversified ladies' and men's watches and clearly does not shy away from extravagant color schemes. For example, models in the AIKON Venturer collection are available in bright pink, a fresh shade of mint, or a flashy yellow and blue color combination.

The hands and indices on the dial of the AIKON Venturer are equipped with Superluminova. The luminous color blends into the design in an enormously harmonious way here and additionally underscores the unmistakable modern character of the watches. Thus, the models from Lacroix are a perfect example of how Superluminova can serve a valuable purpose not only functionally, but also visually.

Conclusion

Starting with radium via tritium to today's modern luminous colors such as Super-LumiNova, Chromalight and LumiBrite, the watch industry has already come a long way in terms of illuminants. Probably the greatest progress has been made in terms of health hazards: Whereas the production of luminous watches used to entail health risks - if not for the wearers, then to a large extent for the workers in the manufacturing process - the practical models can now be produced completely without risk. As a result, we can enjoy numerous, constantly new watches with luminous paint that are easy to read and also benefit in terms of design from Chromalight, LumiBrite, Superluminova and Co.