Fun science: The story behind lume watches


by John Wallis

scroll

May 28. 2019 - by John Wallis

A lot of brands like to boast about how their watches light up at night. But what exactly makes this happen? We talk about phosphorescence, radium and all the technicalities behind the glow. Science doesn’t have to be boring at all: Explore the much-hyped world of watch lume.


Ever since WWI, when commanders wanted their men to be able to tell the time at night, watchmakers have been exploring ways to make this possible. Since traditional watches, including today's top luxury timepieces, do not use electricity, the primary way to light up a watch has been certain kinds of chemicals that are painted onto the dial and hands. The result is an amazing glow-in-the-dark-phenomenon. And while it was initially reserved for soldiers and professionals, lumed watches have gone on to become mainstream, and a much discussed feature among collectors. But how does it all work?

Luminous designs are not restricted to just the watch industry and can be found in various branches with a notable example being in cars. Lighting technology plays a crucial role in motor vehicles that goes beyond the usual safety aspects. Much of that wow factor that you get in cars is generally a reaction when you see some rather fancy lighting. Furthermore, you see light designs being extended to computers, decor and even furniture. It just so happens that watches have more years behind the technology.

A light in the darkness

Phosphorescence is what happens when certain chemicals can absorb light and then emit it. Essentially, the energy transmitted by light photons "excite" the receptive atoms, charging them up and causing them to subsequently emit their own photons. Some chemicals do this over the space of milliseconds - they glow brightly while the light is on them, which is called fluorescence. But other chemicals continue to emit light for much longer periods after the light source is removed. This is phosphorescence, and chemicals that can do it are called phosphors.

The atomic age

Strange to think, but the dangers of radioactivity were very poorly understood by the general public in the first half of the twentieth century. Not long after Marie Curie discovered radium, but before it killed her, the highly radioactive element had been made into paint and was applied to watches by factory workers who were told the substance was perfectly safe.

Radium paint is an excellent phosphor - the radiation itself is an energy source that greatly improves the potency of the zinc sulfide phosphor that is typically added. Radium-painted watches were worn for many decades until the dangers became widely known, and they were banned outright until 1968. Today they continue to be highly sought by vintage collectors - while the glow has faded, they can be identified by Geiger counters, since they will remain radioactive for thousands of years. 

Safety first

Various alternatives to radium have been attempted over the years. Electroluminescence was developed and is used in battery-powered watches - it lights up a phosphor when an electric current is applied with a button press. Such technologies are seen as unsuitable for mechanical watches.

Some manufacturers replaced radium with tritium, another radioactive chemical, but much less powerful and posing no health risk to the wearer, since it is stored as a gas in little tubes. Tritium shines brightly and cleanly, but the downside is its half-life of about 12 years, after which it fades away. Still, it is used with some success today by brands such as Ball and Luminox.

A new light

By the late 20th century, a new solution had been found in the unassuming form of strontium aluminate. In many ways, it was a miracle. Unlike other phosphors, strontium aluminate does not require an energy source to work (such as radiation or electricity). It has the capacity to simply absorb and emit a large amount of light. It literally glows in the dark by itself.

Even better, it continues to do this as long as new light is supplied. No one knows how long it will take for it to stop working, since it's a relatively recent invention, but it clearly lasts several decades at the very least. Indeed, strontium aluminate's only limitation is the necessity for new light. Where radium and tritium dials glow permanently at all times, this non-radioactive, non-toxic lume fades over the course of about seven hours.

The substance was discovered in 1993 in Japan, and in 1998 it was rebranded with the somewhat more glamorous name of Super-LumiNova. Soon, this brand of lume was supplying virtually the entire Swiss watch industry, and it remains the industry standard today.

A few notable watches using quality lume:

Panerai Radiomir 8 Days Ceramica

Panerai has a special connection to watch lume, since it was one of the first to invent radium-based watch paint. It filed the patent for this in 1916, long before it even produced its own watches. The Radiomir series is named after this original lume, although today it uses Super-LumiNova, as in this gorgeous ceramic example. 

SHOP: Panerai Radiomir 8 Days Ceramica

TAG Heuer Formula 1 Calibre 16

This is an excellent new model in TAG Heuer's ever-popular Formula 1 series. With a Swiss-made mechanical movement, it's a superb sports watch even beyond its sleek good looks. Try it out in the dark to see the lume really shine.

SHOP: TAG Heuer Formula 1 Calibre 16

Omega Speedmaster Dark Side of the Moon

The Dark Side of the Moon is a twist on the beloved Speedy known for its high-tech materials - including a zirconium oxide ceramic case and chromium nitrate tachymeter. Omega fans also appreciate the excellent quality LumiNova that perfectly fits the space theme.

SHOP: Omega Speedmaster Dark Side of the Moon

Rolex Submariner Date

The Sub is of course probably the most famous and desirable diving watch in the world. And diving watches are perhaps the foremost cases for watches where the lume really matters. Rolex uses its own branded lume, "Chromalight", which is comparable in quality to Super-LumiNova (some speculate it's the same thing).

SHOP: Rolex Submariner Date

Breitling Superocean 44 Special

Despite being known primarily as an aviation-based brand, the Superocean diving watch has proved highly successful and well-received for Breitling. It's reliable, good-looking and highly legible, especially in the dark where the chunky hands and indexes dazzle.

SHOP: Breitling Superocean 44
John Wallis

by John Wallis

Living and working in London, John has been writing about watches since graduating university. He got his start at SalonQP, London's finest watch show, where he was inspired by the breadth and creativity of the modern industry. His fascination with mechanical horology has only grown from there.

Exceptional Service

Providing excellent customer service is one of our top priorities. We deliver your watch fast and with utmost attention to detail. Should you be looking for a specific model which is not in stock, we are happy to source it for you - free of any extra charges. If you would like to sell a watch, our experts will advise you on market developments and the ideal selling price for your timepiece.

Should you have any questions regarding delivery, price or history of a specific model, your personal advisor will be happy to help at any time.

+1 800-401-6677

Guaranteed Authenticity

We always guarantee a safe transaction. When you buy or sell a watch on CHRONEXT, your contract of sale is made directly with us. We take legal responsibility for every transaction and provide the highest data security standards, secure payment methods and fully insured shipment. In order to ensure the authenticity and quality of all watches sold through us, every timepiece is thoroughly checked by our watchmakers before it is ever shipped to our customers.

This is guaranteed through our Certificate which you will receive with the purchase of any watch from CHRONEXT - new or pre-owned.

Fair Prices

Only the best is good enough for our customers. This goes for prices just as well as for service and security. Luxury watches are hardly ever cheap but there are still significant differences in price levels depending on where you shop. Thanks to our vast global network of suppliers and our low fixed costs, we are able to provide competitive prices at all times.

We scan the market daily for the best offers and always keep our prices up to date. Most important however is that our competitive prices will never lead us to compromise security and quality.

Change of Shipping Country

You have changed your shipping country. When changing this setting between an EU-country and a country outside of the European Union prices shown in the shop are automatically adjusted to reflect local VAT in the shipping country in some cases.

Ok
×
CHRONEXT Boutique Berlin

Opening hours

MON - FR 10:30 a.m. to 7:30 p.m.
SAT 10 a.m. to 6 p.m.

Address

CHRONEXT Boutique Friedrichstraße 71
10117 Berlin
DE

Phone

+49 221 97580604

E-Mail

support@chronext.com
CHRONEXT Boutique
×
CHRONEXT Boutique London

Opening hours

MON - FR 10:30 a.m. to 6 p.m.
SAT. 12 p.m. to 6 p.m.

Address

CHRONEXT Boutique 53 Fleet St
London EC4Y 1BE
GB

Phone

+44 20 3588 0044

E-Mail

support@chronext.com
CHRONEXT Boutique
×
CHRONEXT Lounge Hamburg

Opening hours

MON - FR 9 a.m. to 6 p.m.
SAT 9 a.m. to 5:30 p.m.

Address

CHRONEXT Lounge Ballindamm 39
20095 Hamburg
DE

Phone

+49 221 97580604

E-Mail

support@chronext.com
CHRONEXT Lounge
×
CHRONEXT Lounge Vienna

Opening hours

By appointment only

Address

CHRONEXT Lounge Kohlmarkt 8-10
1010 Wien
AT

Phone

+49 221 97580604

E-Mail

support@chronext.com
CHRONEXT Lounge
×
CHRONEXT Lounge Munich

Opening hours

MON - FR 9 a.m. to 6 p.m.
SAT 9 a.m. to 5:30 p.m.

Address

CHRONEXT Lounge Maximilianstraße 2
80539 München
DE

Phone

+49 221 97580604

E-Mail

support@chronext.com
CHRONEXT Lounge
×
CHRONEXT Lounge Frankfurt a. M.

Opening hours

MON - FR 9 a.m. to 7 p.m.
SAT 9 a.m. to 5:30 p.m.

Address

CHRONEXT Lounge Taunustor 1
60310 Frankfurt a. M.
DE

Phone

+49 221 97580604

E-Mail

support@chronext.com
CHRONEXT Lounge
×
CHRONEXT Lounge Cologne

Opening hours

MON - FR 9 a.m. to 8 p.m.
SAT 10 a.m. to 6:30 p.m.

Address

CHRONEXT Lounge Lichtstraße 25
50825 Köln
DE

Phone

+49 221 97580604

E-Mail

support@chronext.com
CHRONEXT Lounge
×
CHRONEXT Lounge Zug

Opening hours

MON - FR 9 a.m. to 6 p.m.
SAT 9 a.m. to 5:30 p.m.

Address

CHRONEXT Lounge Feldpark 9
6300 Zug
CH

Phone

+41 41 539 10 90

E-Mail

support@chronext.com
CHRONEXT Lounge
×
CHRONEXT Lounge Sydney

Opening hours

By appointment only

Address

CHRONEXT Lounge 235 Clarence Street, Level 1
Sydney NSW 2000
AU

Phone

+61 3 9071 1811

E-Mail

support@chronext.com
CHRONEXT Lounge
×
CHRONEXT Lounge Maastricht

Opening hours

TUE - SAT 10 a.m. to 6 p.m.

Address

CHRONEXT Lounge Stokstraat 24-26
6211 GD Maastricht
NL

Phone

+49 221 97580604

E-Mail

support@chronext.com
CHRONEXT Lounge
×
CHRONEXT Lounge Melbourne

Opening hours

By appointment only

Address

CHRONEXT Lounge 330 Collins Street, Level 14
Melbourne VIC 3000
AU

Phone

+61 3 9071 1811

E-Mail

support@chronext.com
CHRONEXT Lounge
×
CHRONEXT Lounge Toronto

Opening hours

By appointment only

Address

CHRONEXT Lounge 1 University Avenue, 3rd Floor
Toronto, ON M5J 2P1
CA

Phone

+1 416-800-2490

E-Mail

support@chronext.com
CHRONEXT Lounge
×
CHRONEXT Lounge Hong Kong
CHRONEXT Lounge
×
CHRONEXT Lounge Vancouver

Opening hours

By appointment only

Address

CHRONEXT Lounge 333 Seymour St
Vancouver, BC V6B 5A7
CA

Phone

+1 416-800-2490

E-Mail

support@chronext.com
CHRONEXT Lounge
×
CHRONEXT Lounge Montreal

Opening hours

By appointment only

Address

CHRONEXT Lounge 3 Place Ville Marie, Suite 400
Montreal, QC H3B 2E3
CA

Phone

+1 416-800-2490

E-Mail

support@chronext.com
CHRONEXT Lounge
×
CHRONEXT Lounge List auf Sylt

Opening hours

By appointment only

Address

CHRONEXT Lounge EKZ Lister-Markt Hafenstr. 2a
25992 List auf Sylt
DE

Phone

+49 221 97580604

E-Mail

support@chronext.com
CHRONEXT Lounge
×
CHRONEXT Lounge Brisbane

Opening hours

By appointment only

Address

CHRONEXT Lounge 307 Queen Street, Level 9
Brisbane 4000
AU

Phone

+61 3 9071 1811

E-Mail

support@chronext.com
CHRONEXT Lounge
×
CHRONEXT Lounge Perth

Opening hours

By appointment only

Address

CHRONEXT Lounge 152 St Georges Terrace
Perth WA 6000
AU

Phone

+61 3 9071 1811

E-Mail

support@chronext.com
CHRONEXT Lounge
×
Thank You for Subscribing

Thank you for subscribing to our newsletter! You will receive an email from us shortly. Please check your inbox and confirm your registration to start receiving updates from the world of fine timepieces.

Continue shopping
Error

An error has accured while registering your e-mail for our newsletter. Please try again.

Ok