VISIBILITY IN DARKNESS
Barring electronic solutions like LED lights, there are two main methods to making a watch visible in the dark. The first involves Super-luminova or other such luminous paints, which glow in the dark after being “charged” with light, whether natural or artificial, ambient or directed. Luminous paint can be applied in any pattern and, with some tweaks in production, anywhere on a watch down to its case and lugs. It can also be recharged an unlimited number of times, and a sufficiently thick layer of it will glow in the dark for hours before fading off.
The alternative to Superluminova is self-powered light sources driven by the radioactive decay of tritium gas. To achieve this, tritium is sealed within a glass tube whose inner surface has been coated with a fluorescent material – the (very low levels of) radiation from tritium excites this coating, which glows and gives off light. This glow is constant, and lasts through the night. Tritium, however, has a halflife of just over 12 years – after this period, only half of the tritium gas in each glass tube remains radioactive, which means that the brightness has also been halved accordingly.
|| THE VERDICT ||
Why make a choice between the two? As Luminox has demonstrated with its Colormark Nova series of watches – the two technologies are not mutually exclusive. It makes sense to use tritium-powered light for essential indicators such as the hands and hour indexes, which can then be complemented with Superluminova on other indicators, such as bezel markings.
Luminox Navy SEAL Colormark Nova