====== Luminous color ======
{{wst>image_cr|Omega|Seamaster 300 M GMT|Clearly visible fluorescent color markers (indices, pointer) at the [[Omega Seamaster 300 M GMT]]}}

Persistent or self-luminous luminous colors are used for [[watch]] numerals, indexes and hands, to be read in the dark.

==== Superluminova ====
Previously these luminous colors consisted of radioactive substances, today only phosphorescent colors are used. Prevailed for the average everyday use has the absolutely harmless and non-radioactive [[Superluminova]], which has a relatively long persistence and does not use up.

==== Radium ====
The luminous hands, dials and scales of older watches contained radioactive material with far reaching rays. This presented a danger particularly when the watches were constantly being worn on the body. This was true, for example, for **radium**, which is not used anymore.

==== Tritium ====
Also **tritium** was used, which is recognizable by a dial marking with "T". This is usually found at the bottom edge of the dial or in connection with "Swiss", such as stating "T <25". The numerical value refers to millicurie as a measure of radioactivity.

=== Tritium H3 ===
Where a higher legibility of the dial in the dark, beyond the everyday usual, is needed (eg for military watches), today the lighting system **Tritium H3** is customary. It was developed by the Swiss company mb-microtec (watch brand [[Traser]]). Here tritium gas light sources ensure the illumination a minimal amount of tritium gas - H3 - brings the lighting elements permanently to light, without external charging power supply or a button and 100 times stronger than any comparable lighting system.

===== Weblinks =====
  *[[http://www.info-uhren.de/leuchtfarben-uhren|Uhrenleuchtfarben]] (Sterns Uhrenseiten) (German)
  *[[http://www.tritiumh3-watches.com/|Tritium H3 - Watches]]
  *[[http://www.mbmicrotec.com/|mb-microtec]]


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