The Evolution of Watch Luminescence

The grandeur of watch luminescence continues to evolve over the decades, with new and superior glow-in-the-dark material always being developed or improved upon. Together, we will explore the adventure watch luminescence took in the world of watchmaking.

The Evolution of Watch Luminescence

Starting with the discovery of fire and onward, humans have continued their quest for new and preferable ways to see things in the dark. This quest is what brings us to the exploration of the jaw-dropping evolution of the luminescent material used in the production of watches. Impressively, over the many years that this material has been helpful in the watchmaking industry, it keeps proving helpful with the creation of various luminous timepieces. 

1. First, how does Lume work on watches? 

This depends on the type of lume used. Here is a distinct type of material that functions differently. However, all lumes commonly have particular things about them that can be understood by first understanding a little about how the workings of the science of light.

2. Do luminescent watches last long?

This relies on which of the various distinct types of lume gets applied in the production process. More so, it depends on how much of the lume gets used. Particular watchmakers paint a thin layer of lume on a watch to create that effect. On the other hand, some will use multiple layers for the same purpose. The latter will make it shine brighter and last longer than the other. 

3. What are the constituents of the Lume on a wristwatch?

The lume can be a product of various things. All through past years, the watch industry has used numerous distinct types of lume. There is enough to read about the various kinds of lume used all through history in the watchmaking world.

4. Which timepiece gives off the most amazing Lume?

You can find various brightness levels and colors used when it comes to lumes. In your convenience, you can check out this chart that indicates the difference.

5. How do luminescent watches help? 

Here, we will provide answers to all of these questions. Also, we will illustrate better on the many chemical processes which were used over the years by watchmakers to produce items like hands, dials, numerals, hour markers, and more glow-in-the-dark elements.

Watch Luminescence: Step Into the World of Light Science

For starters, light is a form of energy that emerges on the electromagnetic field as an introductory particle known as a photon. This material is a quantum particle of the EM field. 

This photon is a reliable element that has no mass or electric charge. Plus, it travels at the speed of light literally. In addition, photons are naturally produced when an electron swiveling around an atom soaks up a photon and gets excited. As soon as it calms down to a ground state, it discharges a photon we recognize as a spectacle that we call light.

History of Watch Luminescence Materials

However, let’s not get too drawn away with light or quantum science. It’s time to restore the focus on how the light gets generated and utilized in watchmaking, as well as how the various techniques of generating photons compare to one another in the luminescent material found on wristwatches.

Radium Paint in 1908

Watches in those times used radium as lume. This changed in the 1960s. As a material, Radium can potentially sparkle for over 1,600 years. That is about the half-life of the material wherein luminescence starts to fade. Isn’t that wonderful? What then is the catch? Just as the name implies, this material is radioactive!

• Do radium watches still glow? 

Absolutely! Fortunately, watchmakers have now turned to safer materials. Nevertheless, if you happen to own a vintage watch that has a radium dial and you wish to test if it employs actual radium, use a Geiger meter. Should it go off, it’s the real deal you’ve got.

According to BFS which is the Federal Office of Radiation Protection in Germany, the reason that Radium (Ra-226) was not a production material was not because of the risks it posed to the person wearing the timepiece but rather the risk it poses to the watch manufacturers working on the wristwatch.

Tritium (H-3)

Here is a material that helped in this light up until the mid-1990s and like Promethium, it is a beta-emitter. Also, it is a less toxic alternative to radium. Nonetheless, it is a low-energy beta-emitter that boasts an adequate half-life period of 12.3 years compared to Promethium with only around 2.6 years half-life span.

• Is tritium as a material still useful in watchmaking? 

Currently, Tritium in watchmaking is dubbed as GTLS which is an abbreviation for Gaseous Tritium Light Sources. Also, it gets securely sheltered in small and narrow glass tubes that are less porous than the paint on a dial protected by just the watch glass. 

This material is then further safeguarded by the crystal and case backs when they are what is now known as GTLS-glass tubes. You may find that some watches that employ GTLS are not allowed in countries like Germany where there is a legal limit of 1 GBq. Also, some watches even come with as much as almost twice the limit with up to 15 GTLS and a Tritium activity of up to 1.9 GBq. As for tritium tubes, they are famously used in the production of Ball watches which are known for their very striking dials in low light surroundings.

A good number of watchmakers employed tritium throughout the years in their production including the most celebrated luxury watch brand; Rolex. Rolex stopped using tritium in 1998 as soon as the use of tritium paint became prohibited. Since then, the Swiss watchmaker has turned to Luminova instead.

Promethium (Pm-147)

Next up, we have Promethium which is a material that helps as a less toxic radioactive alternative for Radium for a period. With this material, the threat is lower than radium as it only emits beta particles. However, there is one downside to Promethium. This downside is that the half-life period is barely more than two and a half years. That right there is only a spit in the ocean compared to the over 1,600 years of radium’s mid-life span.

Watch Luminescence: LumiNova from the 1940s

In 1941 a Japanese gentleman with the name, Kenzo Nemoto started a business that sold luminous paint. During the Second World War, Nemoto got contracted by his country’s military to paint the gauges in the aircraft. After the war ended, he wasn’t as occupied with painting for the military and had to go in search of more openings. Majorly, he made his living post-war by painting the hour markers and hands of home clocks before he moved onto wristwatches.

In 1945, shortly after the bombing of Hiroshima and Nagasaki, a period when the Japanese were more wary of the dangers of radioactive substances, Nemoto began thinking of how to create a new non-radioactive luminescent substance. He developed a new phosphorescent material and in 1993 a company he founded in 1962, called Nemoto & Co., created a new form of lume.

Contrary to what its predecessors offered, this wonderful new material is a non-toxic phosphor that doesn’t rot during the lifetime of the timepiece. More so, it is temperature-resistant and unmoved by environmental impacts. Later on, Nemoto was joined by RC-Tritec AG In 1998 and they named the branch that would soon supply the watch industry LumiNova, AG Switzerland. 

It is worthy to note that Kenzo Nemoto was smart enough to patent the material. That patency afforded him the power to license it out to watchmakers who were in search of the latest and most effective glow-in-the-dark luminescent material.

1. What makes up a LumiNova?

Known as strontium aluminate, this material was not a radio-luminescent substance like Tritium phosphoric paint, Radium, or Promethium as it used zinc sulfide. The LumiNova material is virtually 10 times brighter than regular lume. Also, they had color variations ranging between bright blue and bright green. As for the blue hue, it was known to glow for the longest time. However, the green hue’s glow was the brightest eventually.

The new material had to be blended with a chemical component called europium. With that, it could glow. Unlike radio-luminescent materials which were always in a glittering state, LumiNova was “charged” through exposure to light. This light can be from sunlight or artificial light. This material  delivers outstanding nocturnal clarity.

2. What Makes LumiNova Different from Super-LumiNova?

Super-LumiNova is the name under which LumiNova was circulated by LumiNova AG Switzerland. When you find the word Super before the LumiNova it suggests that it was a product made in Switzerland entirely. 

A Swiss company known as RC Tritec AG was founded In 1993. This company has the licensing and rights to manufacture and distribute LumiNova under the registered brand of Super-LumiNova. We must mention that LumiNova didn’t stop there, however. Seiko also authorized the material for the production of their LumiBrite timepieces. Also, the well-known Timex Indiglo is one more example of the prosperous licensed rebranding of this product.

On the flip side, Super-LumiNova comes in an assortment of shades and intensities of radiance. Super-LumiNova is a material with a variety of distinct grades as well. These varieties include Standard Grade, Grade A and the highest grade of Super-LumiNova known as Grade X1. The latter, according to ISO 3157, has legibility which boosts the legibility by a factor of 1.6 when you check out the new Swiss Super-LumiNova material.

3. The Workings of Super-LumiNova

According to RC Tritec, this material functions like a light storage battery. If you want Super-LumiNova to glow, firstly you need to ‘charge’ through exposure to light. Don’t forget that natural light will also charge the lume. 

Plus, you must also understand that sunlight delivers the best impact. With the contact of the light on the phosphorescent material, it fascinates the electrons and starts to charge quickly. That is enough to generate a glow.

Below are the numerous colors of Super-LumiNova? Check out any of these numerous shades of colors with numerous intensities of brightness delivered

• C3 is the most luminous with a cream-colored shade. We’ll benchmark the radiance of the other colors against C3 which has, for the sake of this comparison, a brightness of 100%.
• BGW9 is white and comes with about 95% brightness unlike C3
• C5 comes with a mint green tone and 89% brightness unlike C3
• Natural comes with a tint of natural sunlight and a brightness of 87% unlike C3
• Light blue cones with a brightness of 87% unlike C3
• C7 comes in a teal hue and a brightness of 84% unlike C3
• C9 comes with a pale turquoise shade and a brightness of 83% unlike C3
• Light green gives a hue of 82% unlike C3
• Dark green presents a brightness of 77% compared to C3
• Light yellow comes of with a brightness of 72% unlike C3
• Dark blue comes with a brightness of 60% unlike C3
• Light orange gives off a brightness of 54% compared to C3
• Dark yellow comes in a brightness of 50% unlike C3
• Light red presents a brightness of 48% unlike C3
• C3 dense comes in an-off white color and has a brightness of 43% compared to C3

4. Comparing Super-LumiNova and Chromalight

Chromalight just like Timex Indiglo and Seiko LumiBrite is a licensed rebranding of LumiNova. Here is practically LumiNova C9. With LumiNova still holding the patent on the material and Chromalight being a product of strontium aluminate, it’s indeed all Rolex’s solid marketing department. This department finished work on the branding so superbly.  

There is a chance, however, that like other watchmakers, Rolex applies the substance in a distinct way to make the most of the lume. Rolex applies a bright white base under the luminous material, for instance. Besides, the more layers of lume you use, the brighter it will sparkle. Certain brands like Lum-Tec use as much as 6 to 8 coats of lume. They aim to maximize visibility in low light conditions on their wristwatch.