What is luminous and how does it work

BRIEF HISTORY

Watch dials between 1910 and 1920 were painted with radium by women using brushes. This technology was cutting edge at the time. After over 40 years, in 1968, radium use was banned and instead safer alternatives began being used.

(Daily Herald Archive/SSPL/Getty Images)

PHOTOLUMINESCENCE

Photoluminescent pigments, which are not radioactive, are most commonly used today. Almost all modern watches have photoluminescence pigments applied to their hands, numerals, or dials. It works by absorbing light or UV and the stored energy releases visible light, which causes it to ‘glow in the dark’. Easily charged by exposing it to sunlight, or artificial light. The glow lasts about seven hours or so in the dark, depending on its quality and grade. Swiss brand Super-LumiNova brought the method into mainstream and today is one of the best and largest suppliers.

SUPER-LUMINOVA

Lets take an in-depth look at the different varieties and grades you get with Super-LumiNova, the brand that is also being used by NOVE Watches. There are eight available colours.

  • BL - Blue Line 

  • GL - Green Line 

  • VL - Violet Line

  • WL - White Line

  • YL - Yellow Line

  • OL - Orange Line

  • PL - Pink Line

  • UL - Ultramarine Line

Most watches will use one or more of the following colour codes:

  • C3 - Yellow with the brightest glow

  • BG W9 - Light Bluish-white with about 95% glow of C3

  • C5 - Greenish-yellow with 89% brightness

  • C7 - Green with 84% brightness

  • C9 - Bluish-green with about 83% brightness

  • C1 - White with about 31% brightness of C3

The three available Swiss Super-LumiNova qualities are:

  • Standard Grade

  • Grade A

  • Grade X1

NOVE automatic watches use Super-LumiNova GL C3.

TRITIUM

A phosphor-coated borosilicate glass encapsulates tritium in gas form. The tritium gas undergoes beta decay, which releases electrons, causing the phosphor to glow. Thats the basic rundown on how it is. Their luminescence doesn’t fade away after a few hours, and has a half life of 12 years. After about 24 years only a quarter of the radioactive material remains and the tritium gas tubes will no longer glow, requiring replacement.

ELECTROLUMINESCENCE

When a current passes through a phosphor, electroluminescence takes place, resulting in the production of light. In a watch, a glass or plastic panel is coated with an electric conductor and a phosphor, then is mounted behind the dial. The phosphor reacts to an electric current delivered on demand, and acts as a backlight upon activation. The most common application for this is in digital watches.

WHAT ARE THE BENEFITS OF LUME

It enables legibility in all lighting conditions, which can be particularly useful when diving, hiking, camping and other activities during low lighted situations; e.g. dive watches, tool watches and active watches.