Rolex Luminous Materials Guide

rolex batman chromalight with luminous materials

One of the frequently touted advantages of tool watches is their legibility. Often equipped with lume, their most practical use is to be able to tell time in the most difficult conditions – in murky waters, inside a cave or in the dark.

First developed around WWI, the use of lume was driven by soldiers’ need for watches that are easy to read in low light. Since then, several materials have been used to make markers glow in the dark. Today, Rolex leads the pack with Chromalight, a material that is said to glow more than double the time of other luminous materials.

 

In this guide, we’ll take a closer look at Rolex luminous materials, and every material they have used throughout their history.

 

GMT Master Bakelite
Rolex GMT Master Bakelite Bezel ref 6542  |  photo: Phillips

RADIUM

The first luminous material used in Rolex watches was radium; and it remained the standard until 1963.

Before then, the effects of radiation exposure were not well understood, until the highly toxic material caused radiation poisoning among factory workers. At some point, Rolex even recalled Rolex GMT-Master ref 6542 watches with radium bezels and replaced them with aluminum bezels free of charge.

Because radium was ruled unsafe, Rolex phased out radium altogether and replaced it with Tritium.

 

Rolex Seadweller Vintage
Rolex Seadweller Vintage Steel Mens Watch 1665

TRITIUM

Just like radium, tritium is also radioactive, albeit with a much lower level of radiation, and also a shorter half life.

With a half life of 12.5 years, tritium paint on watch dials and hands will lose their ability to glow over a few decades. Moreover, as tritium ages, its color changes, creating a yellowish patina on luminous markers of vintage Rolex watches.

While they are substantially safer than radium, tritium watches are still radioactive, that’s why watchmakers marked the dials with the level of radioactivity emitted by the watch. Most Rolex watches with tritium markers have the symbols “T Swiss T” or “SWISS T<25” below 6 o’clock to indicate that it uses the radioactive material.

 

Explorer II White Dial
Rolex Explorer II White Dial Automatic Steel Mens Watch 16570

LUMINOVA / SUPER LUMINOVA

With tritium having its own flaws, Rolex search for a better alternative. In the 1990s, Japanese company Nemoto and Co developed Luminova – a photoluminescent material that is not radioactive, making it completely safe for wear.

Rolex began using Luminova in 1998. Aside from being non-radioactive, an added benefit of Luminova is that it doesn’t discolor over time.

By 2000, Rolex had switched to Super Luminova, an improved version of the Luminova that is sold through a different company. Both Luminova and Super Luminova need to be charged by light to give off an afterglow; and both give off a glowing green color in the dark.

 

Chromalight
Rolex Chromalight gives off a blue hue  |  photo: Rolex

CHROMALIGHT

Finally, in 2008, Rolex unveiled their exclusive photoluminescent material called Chromalight. This is the first luminous material to be developed by Rolex.

Chromalight, according to Rolex, glows more quickly and can last up to eight hours, which is more than double the time of other luminous materials. Moreover, rather than green, it gives off a blue glow-in-the-dark hue, which is said to be easier for human eyes to read in the dark.

First introduced with the Rolex Sea-Dweller Deepsea, all current Rolex Professional watches now use the blue Chromalight display on their dials.

 

Milgauss
Rolex Oyster Perpetual 39 and Rolex Milgauss Black Dial

Not sure what kind of lume your Rolex has? For vintage Rolex watches, check the date of production, or look for the tritium marker at 6 o’clock.

For modern watches, simply turn off the light and watch it glow. Whatever color it may be, a Rolex performs well in the dark because of its superior lume.

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SEE MORE OF THE WATCHES IN OUR VIDEO:

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