It won’t grow if the watch is dried out and water tight, but it won’t get better. It means it got damp in that watch at one point- maybe not wet, but fogged crystal damp.
I have seen slow spreading of mold on lume plots (dial or hands). It's so gradual, you would probably only notice it by comparing photos taken years apart.
Would exposure to UV (like sitting in the sun for a few days) kill it? Perhaps take the dial/movement out of the watch and set it in the sun/fresh air? Maybe exposure to a ozone generator?
Thanks for all of your responses. I certainly would not have guessed mold.
The dial does look amazing in person with the naked eye so I wonder how much this hurts the overall value.
Would exposure to UV (like sitting in the sun for a few days) kill it? Perhaps take the dial/movement out of the watch and set it in the sun/fresh air? Maybe exposure to a ozone generator?
UV might work, but I would avoid ozone. It is pretty nasty:
"Ozone can cause substantial damage to a variety of materials such as rubber, plastics, fabrics, paint and metals. Exposure to ozone progressively damages both the functional and aesthetic qualities of materials and products, and shortens their life spans."
Source: https://ww2.arb.ca.gov/resources/fact-sheets/ozone-effects
Drying might work. Open the crown and put the watch in a Tupperware container with a couple desiccant packets for a week or two.
@watchyouwant - too funny. I appreciate the fact that you are willing to help relieve me of this burden.
There are always exceptions
