Calling on rolex lume specialists

[rafteur]

Hi guys,

Wondering if someone can help me figuring this one out:

As you know, I bought a 1998 U4xxx Explorer 2 polar dial;

It came with SEL link stamped Z ( I believe Z = 1997 from what I could recoup from my search), and with a tritium dial.

The dial does not glow, but when I am in extreme darkness, there is a faint greenish glow to it. Under blacklight, all the lume parts react in a uniform manner.

Now under the sun, the dots and arrows remain white. A friend of mine who has an A series swiss dial with luminova, the lume immediately shows a strong green on the dots and arrow.

So I am wondering, can it be that mine has a tritium in a final stages of dying? I read here and there that the latter U series had a tritium dial but luminova lume, yet the reaction is different from the A swiss model I seen.

Can anyone help me shade some light (no pun intended)?

Thanks for helping me out putting this puzzle together

Best- Rafteur