In the course of the development of the watches, there was a growing need that the time should be readable in the dark. With the development of diving watches this was absolutely necessary. In order to be able to read a watch in complete darkness, luminous masses were used in the production of dials, hands and later also in bezels. In contrast to previous manufacturing processes, today's luminaries no longer contain any radioactive substances. The simplest way to do this is to say the following about how luminaires work. The basic principle is that phosphorescent crystals are introduced into a carrier layer (lacquer), which also contains molecules which are excited by UV light incidence. These emit electrons after elimination of the light source and thus bring the phosphorescent crystals to the afterglow. There are several ways to enable the time to be read in complete darkness. With tritium, a natural isotope of hydrogen or the Trigalight® light system, the Swiss company MB-Microtec AG, two widespread possibilities would be mentioned. Luminova, originally the Japanese company Nemoto & Co Ltd. Has become one of the most widely used luminaires in the watch industry. In these inorganic, phosphorescent pigments, the electrons, as described in a simplified manner, are brought to a higher energy level by supplying artificial or daylight. The stronger the light incidence, the more electrons move to a higher energy level. By eliminating the light- Energy source, the electrons fall back to their original energy level. This produces the afterglow, also called phosphorescence. The development of Luminova is called Superluminova and has a much higher luminosity. There are different Superluminova varieties.
Superluminova C1 has a neutral pure white color in daylight. The disadvantage is that Superluminova C1 has only about 35 percent of the luminosity of Superluminova C3.
Superluminova C3 has a yellowish hue in daylight. Superluminova C3 is the brightest of all Superluminova varieties.
Superluminova BGW9 has a white color in daylight. In the dark, the elements are colored to a light blue hue. The luminosity is about 95 percent in direct comparison with Superluminova C3. Superluminova BGW9's luminosity is superior to that of Superluminova C1 and Superluminova C3.
Superluminova "Old Radium"
Superluminova "Old Radium" has an orange tint in daylight, giving the watch a certain vintage character. The afterglow takes place in a yellow-green color and is of high intensity.