If the lume on your watch only glows faintly or doesn’t seem to glow at all, in most cases it’s not faulty. The Super-LumiNova® lume needs to absorb light first before it can glow visibly in the dark.
How does Super-LumiNova® work?
Super-LumiNova® is an afterglow lume. It absorbs light energy and then gradually releases it again in the dark.
This means: the lume doesn’t glow on its own permanently, but first needs to be “charged” by a light source.
How can I charge the lume?
Hold your watch under as bright a light source as possible for a while, or expose it to bright daylight.
Good options include, for example:
- bright daylight
- sunlight
- a bright lamp
The more intense the light source, the stronger the initial glow tends to be.
If the watch has been kept in the dark for a longer period beforehand – for example in a drawer or watch box – the lume may barely be visible at first.
Why does my watch glow very brightly right afterwards and noticeably weaker later on?
This is completely normal.
Immediately after strong exposure to light, the glow is at its brightest. The Super-LumiNova® then gradually releases the stored energy again and becomes progressively weaker.
The glow therefore does not stay constant the whole time.
The brightness can decrease noticeably in the first few minutes in particular. After that, the lume continues to glow more faintly.
Should the watch glow equally bright all night?
No. The fact that the lume appears noticeably weaker after a few hours than immediately after charging is due to how it works, not a fault.
How long the afterglow remains visible to you also depends on several factors, for example:
- how much light exposure the lume received beforehand
- how long it was exposed to light
- how dark the surroundings are
- how much your eyes have already adjusted to the dark
- how much lume is applied to the hands and indices of the particular model
The perceived glow can therefore vary from model to model and depending on the surroundings.
Why can I sometimes barely see the lume?
In surroundings that are still relatively bright, the afterglow can be much less noticeable.
Your eyes also need some time to fully adjust to darkness. Lume that initially appears very faint can therefore become much more visible after a few minutes in complete darkness.
Is Super-LumiNova® permanently active?
No. The lume is activated by light and then loses its stored glow energy again afterwards.
However, you can recharge it at any time by exposing the watch to a light source again.
How to test the lume on your watch
If you’d like to check whether the lume is working properly:
- Hold the watch under a bright light source for a while, or expose it to bright daylight.
- Then take the watch into as fully darkened a room as possible.
- Check directly after the exposure whether the hands and/or indices glow.
- Observe how the brightness then slowly fades.
If the lume glows clearly right after intense exposure to light, it’s working as intended.
Do all STERNGLAS models glow equally bright?
Not necessarily.
The perceived glow can vary depending on the model. What matters, among other things, is which elements the lume is applied to and in what amount.
A watch with larger luminous areas, for example, may appear subjectively brighter than a model with very fine hands or small luminous indices.
When should I contact our customer service?
If the lume is not visible at all even immediately after intense exposure to light in complete darkness, feel free to get in touch with our customer service.
Please send us the following, if possible:
- the exact model of your watch
- your order number, if available
- a brief note on how you charged the lume beforehand
- ideally, a photo of the watch immediately after charging, taken in as dark surroundings as possible
This helps us better assess whether the glow is within the normal range or whether a check makes sense.