In the world of watches, lume plays a vital role in improving visibility, especially in low light conditions. However, a common question is how long does watch lume last? The most common watch lume are composed of pigments based on photoluminescent materials. In the absence of light, the lume time is usually about 7 hours. It’s great to know how long a lume watch last, but not many people understand how does watch lume work, so in this comprehensive guide, we’re going to delve into what lume on a watch is, how long watch lume last, how watch lume works, tritium vs luminova, and everything else about luminous watches.

What is lume on a watch?

Nowadays a luminous watch is a watch that glows in the dark, even in a dark environment such as when you’re scuba diving or in the middle of the night, it can easily allow you to see the time. The most common type of watch lume is made up of pigments based on photo luminescent materials. This is a non-radioactive substance, similar to radium, which is applied to watch hands,watch bezel and dials and glows in the dark by absorbing and re-emitting light. Photo luminescence is the activation of luminescent materials when exposed to natural or artificial light, which in turn emits light.

The radium mentioned here was the material used for luminous watches in the early 1900s, but because radium is radioactive, this radioactivity can remain for decades and can be harmful. Watches manufacturers therefore realized that accessories such as radium-coated dial hands were not sustainable.
So they started looking for an alternative material and found tritium. Tritium is a radioactive form or “isotope” of hydrogen that is somewhat radioactive, but a safer alternative to radium, which was the main material used in luminol until the 1990s, when it was banned in 1998.
And today’s watch fluorescents are the photoluminescence just mentioned, but this material only lasts for about 7 hours. So the search for new luminescent materials continues and finally Luminova, Super-Luminova and Tritium tubes have been found.

Luminova and Super-LumiNova

In 1941, a Japanese man named Kenzo Nemoto started a luminous paint business. During World War II, he supplied the Japanese military with glow-in-the-dark paint business. After the war, the Japanese military’s need for this service decreased, so he began to paint watch hands and upper scales on watch faces, and further developed phosphorescent pigment technology. In 1993, this technology was officially named Luminova, patented and licensed to other watch brands and manufacturers.
In the same year, the Swiss company RC Tritec AG was founded and registered as Super-LumiNova, with a license to produce and sell LumiNova. The Super-Luminova is therefore a Japanese invention but Swiss made.

Tritium tube watch

Tritium tubes are now used in a different way than tritium as a fluorescent agent as mentioned above. In the past, tritium was applied directly to watch dials with no protection. In contrast, tritium is now made into a gas and sealed in a tube, making it virtually risk-free.

Tritium is sealed in a tube in the form of a gas, this is called a tritium tube, tritium gas tubes are usually mounted on faces or watch hand. The luminous principle of tritium tube is that the inner wall of the tube is coated with phosphorescent material in the mineral glass washed into the gaseous tritium, tritium and phosphorescent material react to produce a cold light source, this light source does not have dazzling light and heat dissipation, so there is no need to rely on any source of light, to achieve the self-luminescence of zero energy consumption. Tritium watches can withstand deep-sea operations, high vibrations, and harsh extreme environments, and can emit light for up to 25 years. That’s why some dive watches now have tritium tubes on the watch hand and hour marker on watch dial.

How long does watch lume last

As mentioned earlier, in the absence of light, luminova watches typically glow for about 7 hours. However the luminescent coating of super-lumiNova lasts for the entire life of the watch. This is because it works like a battery, storing energy and emitting light continuously and repeatedly. Tritium tubes watch can glow for up to 25 years.Hence the customer can customize and design the watch according to their needs by choosing the right luminous material.

How does watch lume work?

Luminous watch work on the principle that photons from a light source are stored by the photo luminescent material. In the watch industry, this material is generally referred to as phosphorescent material. In a dark environment, a watch accessory coated with phosphorescence such as a watch hand or hour marker on dial slowly releases the light.

Tritium vs luminova

Tritium and luminova are two common luminescent materials used in watches. Both materials use phosphors in the luminescence process, and the principle of luminescence is that the luminova material undergoes some chemical reaction. The difference is that luminova is in powder form and is usually printed or coated on the dial. However the luminova watch hand or hour marker need other light source to charge. Tritium, on the other hand, is a gas encapsulated in a tube, typically mounted on a dial, and does not require an external energy source.

About Super-LumiNova

The super-LumiNova mentioned above is manufactured by the Swiss company RC Tritec AG. Customers buying watches with Super-LumiNova luminescent material are confused by specialized slang such as C3, BGW9, Grades, Afterglows. So we will introduce Super-Luminova in detail to help customers make the right choice.

Super-Luminova is available in a variety of colors with the following color codes:

C1 – White, approximately 31% as bright as C3

C3 – yellow, the brightest

C5 – yellowish-green with 89% brightness

C7 – green with a brightness of 84

C9 – blue-green with a brightness of approximately 83

BGW9 – light blue-white, about 95% as bright as C3

Old Radium – appears as an aged/vintage tritium fluorescence during the day, but glows a bright yellow-green color at night.

Old White – off-white during the day, yellow-green at night

Super-LumiNova grades:
Standard
Grade A
Grade X1
Grade X1 is the latest formulation of SLN. According to RC Tritec, X1 grade provides a 60% increase in brightness after two hours. This increase is based on a comparison between standard and X1 grades.
Note: Not all colors/pigments are available in all grades. For example, C3 (green) is available up to X1 grade, but BGW9 (white) is only available in standard or A grade.

Conclusion-How long does watch lume last?

Watch lume is an essential feature that improves the readability of a watch in low light conditions. For watch enthusiasts and potential buyers, it is important to understand the longevity, principle and function of luminescence. As a professional watch factory, we can customize luminous watch according to customers’ needs and help customers create own watch brand.

At present, our luminous materials include Hong Kong Luminous (colors from HN1,HG2,HL3,HK7,SG-2,SO-02, etc.), Japanese Luminous (J-24B), Swiss Luminous (DS-1,DS-2,DS-3,C3,BGW9, etc.)