Go with the glow

Here they come again! Those lazy, hazy days with nothing to do but relax and listen to the sound of the waves. What better time to refresh mind and body, and what better way to do it than an immersion in the underwater world.

Mask, snorkel, fins and gills for lungs. What more do you need to get better acquainted with the beautiful briny? Er, a dive watch, the horologist will reply. And they are right. Firstly for the unidirectional rotating bezel with which to measure dive time. Secondly for the gauge that alerts us when we are in too deep. Thirdly, and most importantly, for the luminescent glow that will light our way beneath the waves.

The Super solution

Allow us to introduce Mr X. Mr X is taking his annual two-week break at a diving spot. Mr X isn’t the adventurous type. He gets dizzy holding his breath for more than a minute. But he does enjoy snorkelling, so off he goes to buy a dive watch. The salesman is all helium valves and decompression stops. All Mr X needs is a watch he can use to read the time in murky water. Eureka! Or rather, Super-LumiNova®! One of the best phosphorescent products on earth (and under water). It glows strong and long, long enough to read the time while diving at any rate. All dive watches use it these days. It used to be radium, which was dropped because of its radioactivity, then tritium, another luminescent substance, and now Super-LumiNova®. As Longines reminds us, “luminescence is produced when the electrons in a molecule or a crystal are stimulated by an external energy source. These electrons return to their original state very quickly by emitting radiation, sometimes in the form of visible light. In the case of Super-LumiNova®, the energy emitted by the electrons is stored at a relatively stable level, which results in light being emitted over a period of several hours.”

Daylight is instantly transformed into darkness underwater, hence the watch’s various hands must be perfectly visible, and the dial layout simple and easy to read. Breitling ticks all these boxes with its Superocean Heritage Chronoworks Chronograph, a hundred-piece limited edition with a 46-mm ceramic case and Super-LumiNova® on the hour, minute and chronograph hands. The arrow-tipped seconds hand on TAG Heuer’s Aquaracer 300M Calibre 5 Automatic is also coated with Super-LumiNova®, with more for the dot at 12 o’clock on the bezel, which is also engraved with silver-lacquered numerals. The dial of the new Bubble from Corum is brought to life by “leaf” hands that also shine bright with a Super-LumiNova® coating. And what about that rule-breaking bubble shape!

Fiat lux

Although white Super-LumiNova® is the most popular choice, the good news for Mr X is that he has plenty of other shades to choose from, ranging from off-white to pale yellow, as well as more original colours such as red, blue, green, even black. On the Omega Seamaster Planet Ocean Deep Black, both a dot on the bezel and the minutes hand give off a green glow so a diver can check the time at a glance. The contrasting blue luminescence of the other hands and markers adds to this legibility.
Readability is also a key factor of the Rolex Oyster Perpetual Explorer, which makes use of an innovative, long-lasting luminescent substance. The numerals at 3, 6 and 9, the markers and the characteristic hands are all coated with Chromalight, which glows blue, the last colour in the spectrum to remain visible in the dark. As an added bonus, it lasts for up to eight hours. What’s betting Mr X will be out of the water and back on his beach towel before then!