Why does my rep’s lume fade so fast? Straight out of the sun the dial glows like a torch. An hour later I can barely read the hands. Is that just how rep lume is, or did I get a bad one? And is a relume ever worth it, or is that asking for a ruined dial?
Related threads: How long does a rep watch actually last, Swimming with a rep diver, Timegrapher in QC photos: which numbers really matter.
Some of it is how lume works, and some of it is the rep. Every luminous paint is brightest in the first minutes after charging and then decays. Even good lume falls off a cliff early and then glows faintly for hours. So “bright then much dimmer after an hour” is normal on any watch. The real questions are how bright it is after an hour and how long it stays readable.
Where reps fall short is usually the amount and grade of lume applied, not the principle.
The best material on this is a comparison test someone did with about 20 watches, reps and gens mixed. All were charged the same way and then photographed at fixed intervals, over about two hours. After 40 minutes the tritium watch was clearly ahead, and after two hours most of them showed only a trace.
The lesson: you only compare lume with the same charge and the same exposure. A long-exposure photo taken right after a torch says almost nothing.
So how do I tell if a given rep’s lume is actually worse than it should be?
Compare like with like. One owner compared his rep Explorer 36 side by side with his brother’s genuine one. Case, dial and bracelet impressed both of them, and the lume was the one thing that was “not even close”: the gen stayed bright and even, the rep faded.
The opposite also happens. An owner of a recent GMT rep woke up at night and found it still readable, about four hours after only ten seconds of charging with a weak UV torch. Someone else says their Seamaster 300 rep “lasts all night”. So it varies a lot by model and factory. Don’t assume all rep lume is weak, and don’t assume yours is broken because a photo online looks brighter.
Fair-test method, if you want to post a comparison:
Also look at colour vs duration. A very white or very green lume can look brighter in the first minutes than a blue one that lasts longer.
One warning on UV torches. An owner noticed the bezel lume on a new diver starting to yellow within a week, after charging it a few times with a UV flashlight. That’s one report and the cause isn’t certain, but don’t sit a strong UV torch on the lume for long periods just to test it.
On the relume question: it’s a dial job, and the dial is the part you least want to damage. Old lume has to come off cleanly, new lume goes on by hand, and the edges have to stay crisp. Get it slightly wrong and you’ve traded dim lume for markers that look obviously messy in daylight. Daylight is when people actually look at your watch.
Lume can also simply detach. One owner’s 6 o’clock marker fell off a Seamaster rep. A local watchmaker could only remove the crumbled piece and had no matching lume. If you’re opening watches yourself, the NH35 build guide shows how much care dial handling needs.
And one more point: if the lume on the hands and the markers doesn’t glow the same, that’s often visible in daylight too, as a slightly different shade. That’s more a QC issue than a relume issue. Better to check it in the QC photos.
Summary:
For the broader “what wears out first” picture, see how long rep watches last. For terms like lume, pinion or index, see the parts glossary.
That makes sense. What I described sounds like the normal range, so leaving the dial alone is the answer.