Lume not dead after all on mid ‘90s Sea Dweller

[shocken2]

I purchased a mid ‘90s “T <25” Sea Dweller about a while back. When I first got the watch I took it into a windowless room to test the lum. I held it up the light for quite some time then turned the lights off to create a pitch black environment and there was NOTHING. Not even a hint of lume.

Then last week I was sleeping with the watch on, woke up in the middle of the night, and instinctively checked my wrist for the time… the dial was glowing well! I wouldn’t call the lume bright, but it’s perfectly legible.

What gives? I’ve been spending a lot of time outdoors in bright natural light. Would that charge the lume better than artificial light? I’m thrilled that the lume is not altogether extinguished, I’m just at a loss to explain why I couldn’t see it before.
Lume not dead after all on mid ‘90s Sea Dweller

I purchased a mid ‘90s “T <25” Sea Dweller about a while back. When I first got the watch I took it into a windowless room to test the lum. I held it up the light for quite some time then turned the lights off to create a pitch black environment and there was NOTHING. Not even a hint of lume.

Then last week I was sleeping with the watch on, woke up in the middle of the night, and instinctively checked my wrist for the time… the dial was glowing well! I wouldn’t call the lume bright, but it’s perfectly legible.

What gives? I’ve been spending a lot of time outdoors in bright natural light. Would that charge the lume better than artificial light? I’m thrilled that the lume is not altogether extinguished, I’m just at a loss to explain why I couldn’t see it before.

[Strela]

The deal is this: What you are witnessing is the available lume being excited by the inherent energy in the radiation from the tritium it is mixed with, and not from a outside source in the way modern lume, like luminova, works.

[LJUSMC]

The deal is this: What you are witnessing is the available lume being excited by the inherent energy in the radiation from the tritium it is mixed with, and not from a outside source in the way modern lume, like luminova, works.

What he's trying to say is this: Your lume is Tritium, which is mildly radioactive. The lume effect is created by the radioactive material decaying, therefore it is unaffected by bright lights and will only give off light as long as it's still radioactive. Once it's "dead," it will no longer give off any light. Now, go to a rolex dealer and look at one that has been made within the last 10 or so years. The lume on those watches is "Luminova," and is not radioactive. This means that it gets its lume capabilities from an outside light source (ie the sun). However, over a period of time the lume will get dimmer and dimmer and eventually will go completely dark, until it is "charged" by an outside light source again.

[Taswell]

Then last week I was sleeping with the watch on, woke up in the middle of the night, and instinctively checked my wrist for the time… the dial was glowing well! I wouldn’t call the lume bright, but it’s perfectly legible.

Probably another factor at play is that after being asleep for several hours your night vision is better than if you just walked into a dark room and so your eyes are more sensitive to the low level of illumination coming from the old, weak tritium lume.

[shocken2]

That's an excellent piont Taswell. I understand the properties of tritium, it was the fact that no lume was visable in the pitch black that I couldn't understand. I bet you're right that it is the sensitivity to light that made the difference.

Would it be ill advised to ask Rolex to re-apply luminova at the next service? I'd like some brighter lume, but don't want to mess with the origionality.

[Kawika]

Would it be ill advised to ask Rolex to re-apply luminova at the next service? I'd like some brighter lume, but don't want to mess with the origionality
If you wish to not mess with the origionality, then you're going to have to find one of the very few lume restorers in the world...as Rolex, on service, will only replace those hands with current luminova stock...they do not relume their old dial and hand products. If you look long and hard enough, you can find a skilled watchperson specializing in dial and hand restoration, but they don't work cheap and they don't work fast, and you'll either have to send them the entire watch or find your own watchmaker to remove the dial and hands allowing you to do the shipping.

For the purists in the world of 'old' Rolex, such modification is heresy, and if you fall into that religion, then you'd best leave well enough alone. Me? I'm on record wanting my watch to work to its maximum capabilities, so a Rolex hand and dial replacement is just fine when the original starts to lose its function, but I'm not trying to convert anyone to my way of thinking.