one of the most important watchmaking innovations was undoubtedly the illlumination of the dials at night, so that the wristwatch's functions could be used in the dark.
Like many other innovations, luminance systems have military origins, whose use was popularised by shotguns for the purpos of better aiming. Years later, luminance became an indispensable element of a wristwatch. But what makes watches glow in the dark?
The origin of luminance in watches was achieved through Radium around the time of World War I. Radium is a radioactive element which, when mixed with zinc sulphide (ZnS), was able to make an object light up considerably and constantly. This illumination system works without any prior trigger. However, although the amount of radium did not affect the wearer of the watch, even when mixed with ZnS, its level of radioactivity was still very aggressive for both the wristwatches and the workers who made them.
After its ban in 1968, tritium was called upon to replace radium. Mixed with ZnS like radium, tritium achieved a constant luminescence without the need for any other energy source. Tritium is also radioactive, although its level of radiation given off is much lower. This also means a shorter half-life (12 years compared to 1600 years for radium) and therefore a shorter durability of the luminescent material.
However, there was still some concern about radioactivity in the 1960s. The need to find a photoluminescent material capable of fulfilling this function in a completely safe way was born.
Today, there are three systems that allow our watches to be illuminated without being harmful: luminescent paint, active lighting systems and micro gas tubes (H3), which have led to the resurgence of Tritium.
Photoluminescent materials contain pigments which, through the phenomenon of photoluminescence, this is, the ability of the material to absorb photons from a light source and then emit them.
The most commonly used phosphorescent material in watchmaking is Superluminova: luminescent pigments based on strontium aluminate that manage to illuminate bezels, hands and indices, making them shine 10 times brighter than with conventional pigments.
Also known as Luminova, this system, developed by Neomoto, is not only popular in the world of watchmaking but also, among others, in jewellery, aviation, signage and safety panels.
The difference between this system and the two mentioned above is that these pigments are neither toxic nor radioactive. Superluminova can glow up to 5 times brighter than Tritium, although its brightness drops below that of Tritium after a few hours. For this reason, it is common to find both systems in some watches.
Among its disadvantages is the need to be recharged by sunlight or artificial light, which is influenced by three factors: the length of the predominant wave, the strength and the time of exposure. On the other hand, we can highlight its high durability both during the night and over time.
Thanks to technological advances and the growing importance of personalisation nowadays, Superluminova has gone from being manufactured in the characteristic shades of green and blue to include a wide palette of colours, including some from the Pantone Institute.
MICRO GAS TUBES (H3)
Tritium gas microtubes, also known as Super Heavy Hydrogen, have been one of the most recent lighting systems developed thanks to the laser technology of MB-Microtech AG in Switzerland.
Characteristic of Ball watches, this mechanism hermetically captures the aforementioned tritium gas in boron silicate microtubes coated with phosphorescent paint. These tubes, previously built with a laser, are fixed to the hands and dial of the watch, making it impossible to break them.
Thanks to the chemical reaction, the gas capsules achieve a superior, resistant and really intense brightness, while being completely safe even in case of exposure to the gas inside, thus reducing any risk to the owner of the piece or to the workers who manufacture it. The watch can even be made to glow in different colours, thanks to the paint coating that the manufacturers apply to the microtubes.
This system does not need any trigger or external light source and its intensity is 100 times higher than that of any luminescent paint. It has an average life of 12 years, after which the luminosity will be less intense, although it can last up to 25 years thanks to the treatment that some manufacturers apply to the Tritium. Once this time has elapsed, the watch can be sent to the brand to replace the exhausted tritium tubes with new ones.
Ball and Luminox stand out in this lighting system. Luminox watches are characterised by its LLT (Luminox Light Technology) System. LLT is the Swiss micro gas tube technology that allows their watches to glow constantly and intensely, making them waterproof and shockproof, without needing to be charged.
ACTIVE ILLUMINATION OR ELECTRO-ILLUMINATION
This system requires power from an external battery, so it is not found in mechanical or automatic watches. In general, you will find a specific push button on the quartz watch to illuminate the wristwatch in the dark on demand. It is this push button that activates the electro-illumination.
Each system has advantages and disadvantages, so it will be perfect depending on whether or not it suits your functional, aesthetic and economic needs.
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