"Does keeping the watch in the dark produce the orange tropical or does the light do that?"
That is a very good question. I have no answers, just a few examples:
Bought a new 16760 GMT II in mid 1989 from a rlx AD. It was kept in a dark, dry, room temperature safe, never worn until I sold it in late 1995. The watch was never out in the sun. The hands turned yellowish and the markers stayed white. I paid $1465 for it new, shipped out of state to dodge tax. I knew an 'AD guy' back then. Should have kept it...
Have a nos 6694 that I bought new at an AD in June 1989. Still have it unworn and stored in the safe. The dial marker dots and hands are still white.
A nos 6430 Speedking purchased from a rlx AD in 1972 still has white dial marker dots but the lume in the hands has turned yellowish and there is a slight dark (burned?) spot on the dial under the hour hand where it has been in the same position for many years. The watch has serial number 882xxxx from around 1985 so the hands should have tritium lume. First time I have seen 'trit burn'. Have seen a lot of 'radium burn' on dials though.
Had a nos L96xxxx 5500 AK stored for about 20 years and the lume looked same as new when I sold it, unworn in the box.
Have an old 5500 AK 1520 17j with serial number 544xxxx that has seen a lot of sunny days and the hand and marker lume is yellowed but the dial paint still looks pretty good.
Otoh have a 'like new' (no kiddin') all original black dial 1964 214 Accutron Astronaut (w/Kreisler coffin bct) and the dial still looks good but the hands are showing signs of corrosion from whatever type of lume was used back then...radium? The crystal is mounted on the case by the inner ring of the rotating bezel like a rolex. One of the coolest watches ever made imho.
The burned spot on the Speedking dial is a mystery...to me anyway.
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