The logic of "T" vs "L"
Promethium is a strange one,
It does not normally degrade or discolour like Tritium so the dials tend to look brand new, the half life is so short (about 3 years) that the dials are always dead, it was not a success as a lume material which I presume is why CWC still used Tritium way past the introduction of Promethium dials for MOD watches.
https://uploads.tapatalk-cdn.com/202...922b797914.jpg
This is from 96
https://uploads.tapatalk-cdn.com/202...c17bbd783f.jpg
This is from 08
As an aside
This watch is also promethium and I remember it being really bright when I first got it as a kid but being really disappointed a few years later when it was unreadable at night.
https://uploads.tapatalk-cdn.com/202...bc4a9b673c.jpg