Dial labeling at 6 o'clock

[watchmaniac]

I noticed that there are different labels for the same model watch located at the 6 o'clock of the dial.

SWISS = Radium

SWISS T < 25 = Tritium less than 25 mC.

T SWISS T = Tritium less than 7.5mC

Swiss = LumiNova or SuperLuminova

Swiss Made = SuperLuminova


I also noticed that sometimes the same model year has different labeling as well. For example, a 1999 A series explorer II has Swiss Made and SWISS on some dials. Anyone can shed some light on this?

[Tools]

There is some myth and misinformation in your research..

Luminova and Superluminova are the exact same compound.. It is a patent, and therefore, identical. It was merely a name-change by the maker to denote if it came from the original Japanese factory (Luminova) or the new Swiss factory (Superluminova). Swiss, or Swiss Made are not indicative here because the watchmaker likely didn't know the origination of their compound...

An A serial prefix (there is no such thing as a "series") may have been manufactured anywhere between 1997 to 2000, it cannot be said to be a "1999" watch. Therefore, A serials spanned the Tritium dials, the Swiss and the later Swiss Made dials so may be found with any of those dials.

Swiss was used by Rolex during the first ~2 changeover years, 98/99, but then they also used Swiss dials for service replacements. It is expected that if it is a U or A serial prefix dial with Swiss only, it was likely made during those 2 years: Swiss Made would be later, Tritium would be earlier. Any other Serial may likely have a service replacement.

But this is a generalization as nothing with Rolex is ever an absolute.

[Z-Sub]

The SWISS dial only had a very short run. It contains Luminova within the gold surround on the markers. With the introduction of Superluminova, the dial changed the marking to Swiss made.

honestly, I did not notice any real difference in the lume between the dials.

[HL65]

Swiss only dials are some of my favorites as for me they mean one thing...Radium!!

And yes I am only referring to vintage of course!

PS. You also forgot about Sigma dials since we are on the topic.