Watches with strong luminosity

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

What does "strong luminosity" mean?

For use in watches, luminous materials that have a certain luminosity without having to be heated to a high level are particularly interesting. Although many materials begin to glow with sufficient heat, this heat cannot be generated in everyday use of a watch. Just imagine having to take off your everyday watch at regular intervals to warm it up - that is simply not practical. In addition, in this case all the materials used would have to withstand the required heat. This would undoubtedly severely limit the choice of materials.

In order for watches to glow in the dark, a phosphor is required that has what is known as cold light emission and thus gives off light without the need for intense heat. This is then referred to as luminescence.

To put it simply, luminescence is triggered by the activation of atoms or molecules using chemical, mechanical or electrical processes. During these processes, energy is generated, which is then released in the form of light - the watch is given luminosity. The strength of the luminosity is typically defined by the brightness of the light or the duration of each individual process.

Types of luminous materials

The watch industry now has a wide range of different materials and luminous colours that can help hands, indices and dials to shine. Below we take a closer look at the most common, most widely used and most historic luminous sources for watches:

radium

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

One or two readers are probably wondering how dangerous it is to wear radium watches. After all, radium is generally known for its radioactivity. The answer is therefore quite surprising: radium incorporated into a watch as a luminescent material is almost harmless to the wearer. But how can that be? It's quite simple: the radiation from the radium luminescent material in the Radiomir watches was largely absorbed by the case and therefore had only a negligible effect on the wearer.

However, the buyers of the watches did not even need to be convinced of this fact, as the population of the time was not very skeptical about the material. Quite the opposite: radium was even advertised as healthy and used in a wide variety of foods, care products and medicines. Even if this is hard to imagine from today's perspective, there were radium drinking cures, chocolate with radium added and toothpaste containing radium. So if you consumed radium - or wore it on your wrist - you didn't have to worry at all, but rather had the feeling that you were doing something good for yourself. It was not until much later that radioactivity was associated with all kinds of health risks.

The catch: the watches had to be produced somehow, the workers inevitably came into contact with the radium and the radioactivity certainly did not leave them unscathed. As harmless as they were for the wearer, they were just as harmful for those involved in the production process. The key word here is "Radium Girls". This is what the workers were called who handled the luminous material on the opened watches and ingested a lot of radium. Several of the Radium Girls subsequently had to fight serious cancer - the total number of deaths caused by radium watches is not documented.

tritium and tritium gas

As knowledge of the significant disadvantages of radium increased, the need to find an alternative became increasingly urgent. In the 1960s, tritium, a hydrogen isotope with a twelve-year half-life, was finally introduced. However, this did not solve the problem of radioactive radiation, as tritium is also radioactive, albeit less so than radium. Using tritium was certainly a step forward, but it quickly became clear that a final, truly sustainable solution had not yet been found.

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

Nowadays, Tritium H3 watches are marked with the symbols T, T25 and H3, which are usually found on the dial. Timepieces with tritium as a luminous material have not been manufactured since the 1990s.

LumiNova

The development of the LumiNova phosphor by the Japanese company Nemoto ushered in a new era in the field of luminous watches. 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 luminates, is charged by external light - whether artificial or daylight - with the luminosity being measured by the intensity of the charge. LumiNova is therefore a so-called afterglow paint that can be used to produce light in a wide variety of colors.

Super-LumiNova

The material that makes the watches glow is now known as Superluminova C3, Chromalight or LumiBrite. Which name you find depends mainly on which manufacturer you are looking at. Essentially, it is always one and the same product, albeit in slightly different versions. The background: In the 1990s, both the Swiss company RC Tritec and the watch brand Seiko had the opportunity to purchase the luminescent material from Nemoto almost at the same time and to market it under different names.

While LumiNova has a maximum luminous duration of five hours, watches with Super-LumiNova shine for up to 15 hours before their brightness and luminosity slowly but surely decrease and they need to be recharged. As versatile luminous materials, Super-LumiNova, Chromalight or LumiBrite can be used as luminous paint in green, orange or blue, for example, 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. There are now watches whose entire dial is illuminated by the luminous material, bracelets framed with light, luminous logos and, of course, the classic luminous hands and indices. Watch brands often manage to integrate the Superluminova coating seamlessly into the design and create an optimal overall image.

Advantages and disadvantages of different phosphors

To complete the overview of the common luminescent materials for watches of the past decades, we will make a comparison and briefly discuss the specific advantages and disadvantages of the individual luminous colors.

The disadvantages that put an end to radium and tritium are obvious. The radioactivity of the luminous materials made them dangerous, especially for the workers who had to handle the materials openly. Tritium is less radioactive than radium, but loses its luminosity after just twelve years and is still considered potentially hazardous to health. However, one major advantage of the two previously popular luminous materials should not be swept under the carpet: they did not require any external energy source and did not need to be rhythmically recharged. However, this advantage cannot, of course, make up for the health risks and problems associated with the manufacture, maintenance and disposal of tritium and radium watches. It is therefore hardly surprising that such items are no longer produced today.

In comparison, tritium gas can be described as harmless and is therefore more suitable for use in watches. This luminous color also glows continuously. So no external energy source is needed to make the watch glow with tritium gas. The disadvantage: tritium gas is tied 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 non-radioactive and therefore can be used with significantly less risk. However, unlike tritium, for example, LumiNova and Super-LumiNova rely on external light sources to function as luminescent materials. They must be charged by light in order to be able to do their job, and this must be done regularly. The difference between the two products mainly relates to the duration of the light and the luminescent colors. LumiNova can be seen glowing at full intensity in the dark for a maximum of five hours, while Super-LumiNova can glow for a full 15 hours. In addition, there are significantly more color variants available with Superluminova, which multiplies the optical design options for the dial, indices, hands, etc.

The best watches with strong luminosity

Whether with LumiBrite, Superluminova, Chromalight or a similar, harmless luminous material: many manufacturers offer watches that glow in the dark and are therefore 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 inspires collectors all over the world: the Omega Seamaster Diver 300M. Waterproof to a depth of 300 m, this watch impresses with its sporty design and excellent functionality. Since the first Seamaster came onto the market in 1993, the watches have almost always been among the most sought-after models of their kind. This is probably due in no small part 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 the hands and, where applicable, pearls on the dial glow in green and blue in the dark. The dial itself has the wave pattern that is a typical feature of the Seamaster and gives the timepieces their very own charm. The Seamaster 300M with Superluminova can be purchased from the manufacturer with a metal bracelet, NATO strap or strap made of robust rubber.

Rolex Submariner

The Rolex Submariner is the epitome of a modern, highly functional diving watch. The manufacturer promises optimal readability of the watch, even in the depths of the underwater world, and uses the Chromalight material for this. The luminous color is a characteristic blue and impresses with a luminous duration 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 the Submariner has a lot to offer beyond the Chromalight color. It is water resistant to 30 bar and, thanks to the 60-second engraving on the bezel, helps you read the dive time precisely. The first-class watch is made using Cerachrom, a material that is particularly scratch-proof and resistant to chlorine and salt water.

Panerai PAM 632

After having mentioned the renowned Italian watch brand Panerai several times in this article, we now take a look at a particularly popular model from the manufacturer. The PAM 632 is a hand-wound men's watch, which in terms of design strikes a balance between down-to-earth classicism and modern sportiness.

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 luminous material used, thanks to which the watch with reference number PAM 632 can be read perfectly even at night, is - unsurprisingly - Luminor. This can be found on the indices, the hands and the numbers on the dial.

Breitling Navitimer

As a sought-after pilot's watch, the Breitling Navitimer is a collector's item that has delighted the watch world for around 65 years. Breitling watches are now available in a wide range of different designs - some sporty, some classic and elegant. The models have one thing in common: the integrated luminous material makes them easy to read.

Breitling now uses the luminous paint Superluminova, which can be found on the Navitimer timepieces both on the indices and on the minute and hour hands. In use, a Navitimer watch should be able to score points with a consistent luminous duration of at least eight hours, as confirmed by the experience of wearers. Connoisseurs mostly agree: Among the Super-LumiNova watches, the Breitling Navitimer is one of the best.

Nomos Glashütte Autobahn

If there is a modern watch that can be seen as the embodiment of the 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 a few examples of the outstanding details that characterize this watch. What appears straightforward and simple at first glance contains an unexpected complexity and a variety of functions that we have come to expect from Nomos Glashütte for years.

Made for frequent drivers and those who are often on the roads at night, the Autobahn watch naturally glows in the dark. Nomos Glashütte uses Superluminova for this effect and uses the luminous paint quite generously. The watch dials are provided with a comparatively wide blue luminous ring that is briefly interrupted every five minutes - this means that the dials are almost completely illuminated and can be read easily. In addition to the strongly illuminated dials, the hands are also coated with Super-LumiNova, which makes the overall appearance extremely harmonious both in daylight and in the dark.

Maurice Lacroix AIKON Venturer

The last watch with luminous colors that we will be focusing on in this article is the AIKON Venturer by Maurice Lacroix. Intended as a kind of homage to the Lacroix Calypso series of the 90s, the AIKON Venturer collection amazes with its incredible diversity. It includes a large number of varied women's and men's watches and is clearly not afraid of extravagant colors. For example, models from the AIKON Venturer collection are available in bright pink, a fresh mint tone 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 fits in extremely harmoniously with the design and further underlines the unmistakably modern character of the watches. The Lacroix models are therefore a perfect example of how Superluminova can serve a valuable purpose not only functionally but also visually.

Conclusion

Starting with radium and tritium and ending with today's modern luminous colors such as Super-LumiNova, Chromalight and LumiBrite, the watch industry has come a long way in terms of luminous materials. The greatest progress has certainly been made in terms of health risks: While the manufacture of luminous watches used to pose health risks - if not for the wearer, then certainly to a large extent for the workers in the production process - the practical models can now be produced completely safely. As a result, we can enjoy numerous, constantly appearing new watches with luminous colors that are easy to read and also benefit in terms of design from Chromalight, LumiBrite, Superluminova and co.