Chromalight in Blue,
What Makes It Different?

Since childhood, The glow-in-the-dark stars stuck to the ceiling lights have always glowed green. Most emergency exit signs also use green luminescent lights. Then why do Rolex dive watches use blue luminous paint?

This intense blue luminous paint, Which creates both a sporty and luxurious feel, Is Chromalight, A patented technology of Rolex. The long-lasting nature of Chromalight plays a crucial role in lighting the path for adventurous explorers, Representing the tradition and identity of Rolex’s functional watches. However, Luminous paint was used even before Chromalight was introduced. Let us look at how Rolex, Which has been releasing watches with luminous features since 1953, Has evolved its materials over time.

The First Luminous Paint,
Radium (1953~1959)

Radium / ⓒ REEDSCO

The first luminous material used by Rolex in 1953, Including on the Submariner, Was a synthetic paint mixed with radium. At a time when research on radiation exposure was lacking, Radium was actively used in food, Cosmetics, And the textile industry. Considering its half-life of 1, 200 to 1, 600 years, You can immediately sense how harmful it is to the human body. Although safety measures were taken, Concerns about health grew and Rolex eventually abandoned radium.

A Slightly Safer Radioactive Material,
Tritium (1959~1968)

From 1963 to the 1990s, Rolex used tritium, A substitute radioactive material with reduced radiation levels, As a component in its luminous paint.

Tritium Markings

Watches painted with the radioactive isotope ‘Tritium H-3’ as the luminous material were produced with a ‘T’ marking at the 6 o’clock position on the dial. The photo above shows the types of T markings indicating the level of radiation emitted by the watch.

Patina Watch / ⓒ BOB’S WATCHES

Tritium-based luminous Rolex watches develop a yellowish patina on the dial markers, Indices, And hands as they age. This is because tritium luminous paint changes color over time. Furthermore, With a half-life of 12.5 years, Discoloration begins in less than a decade. Watches with significant discoloration are called patina watches, A nickname inspired by the color change that occurs when certain metals oxidize. Thanks to their unique vintage color, Patina watches remain in steady demand among collectors.

Green Luminova and Super-Luminova
(1993~2008)

Luminova / ⓒ NEMOTO

However, Tritium was also not free from radioactivity, And from 1998 Rolex began using Luminova, Developed by the Japanese chemical company Nemoto & Co., Ltd., Which contains no radioactive substances. Luminova is made only from phosphorescent materials, So it absorbs, Stores, And emits light. As long as the watch is exposed to light in advance, It can glow in the dark.

ⓒ BOB’S WATCHES

Watches from this period typically emit the green glow we are familiar with. The fact that there is no performance degradation despite dial discoloration and the passage of time was also a strong appeal to consumers.

In 2000, Luminova and Super-LumiNova paints, Manufactured and distributed by the Swiss company RC Tritec AG, Were adopted. Rolex watches produced from 1998 to 2000 have a simple SWISS marking at 6 o’clock on the dial, While those produced from 2000 to 2018 are marked SWISS MADE.

The Perfect Blue Light,
Chromalight (2008~)

Chromalight was introduced in 2008 with the launch of the Ref. 116660 Deepsea. It was a symbolic debut, Perfectly suited for the Deepsea, Which is specialized for deep and dark underwater exploration. This special phosphorescent material, Trademarked by Rolex, Emits a blue light that is easier to distinguish in the dark and can last up to 8 hours. With technology that lasts twice as long as ordinary luminous materials, Rolex once again took the lead in the industry.

Ref. 116520 / ⓒ THE WATCH CLUB

Let us look at some features of Chromalight. It shines brighter and lasts longer than Super-LumiNova. Chromalight markers appear noticeably bright white when exposed to light. Chromalight is a phosphorescent material like Super-LumiNova, So if you want your watch to emit a strong blue glow, Exposing it to a light source such as sunlight for a long time will enhance the effect.

Deep Sea 116660

44mm, D-Blue, Oyster

Explorer 2 226570

42mm, White, Oyster

Since 2015, Most Oyster case models have used Chromalight, And the improved luminous duration of Chromalight has been applied to all Professional lines and many Classic lines, Starting with the new Explorer 2 (Ref. 226570) released in 2021. Did you know that experts hand-paint this material onto the watch markers and dials? Special tools are also used to apply the paint evenly and precisely. Because the process is so intricate, It cannot be replaced by machines. The performance of Chromalight is so outstanding that it is impressive Rolex has yet to introduce a replacement, Despite regularly unveiling new technologies.