Here's a late 80's Speedmaster. Nice shape, but the tritium is a little messy. Does this look like a bad relume job, or is it normal for the tritium to start to smear on these dials? Rolex tritium doesn't seem to do this. Thanks!
Well, from what I've been able to dig up, I think you're right. The substrate tends to swell over time due to moisture. And of course some watches are going to have seen more moisture than others - so sometimes you see this bleeding/smearing effect and sometimes you don't. And apparently the primary reason for companies like Rolex to have added the metal surrounds around the luminous material was to prevent this from occurring.
Mmm well my Rolex 1680 Submariner from 1979 hasn't just swelled, its actually flaked off due to moisture intrusion
Look at these pics of a 60s 145-012 from the original owner. Quite a bit of erosion and migration of the luminous material.
Good eye Yea that insert was original to the watch, the whole thing was in near destroyed condition when I got it, the bezel was the nicest part of the entire watch lol