For defination, you can search in so many on-line dictionary like Macmillan, Wikipedia, Miriam-Webster etc.
Extract from the net :
pat·i·na? ?/?pætn?, p??tin?/ Show Spelled[pat-n-uh, puh-tee-nuh] Show IPA
noun
1. a film or incrustation, usually green, produced by oxidation on the surface of old bronze and often esteemed as being of ornamental value.
2. a similar film or coloring appearing gradually on some other substance.
3. a surface calcification of implements, usually indicating great age.
Some Patina is what gives vintage watches their charm, their individuality. Patina is a just a grand term to describe the effects of age on a timepiece. Sometimes, on the right face, in the right quantity, patina can have a tremendously positive impact. Sometimes, on the wrong face or when left unchecked for too long, the impact is wholly negative.
I am not sure what causes patina on Tritium plots. But it could be from the environment, or the dial material, or the paint. If there is real radium on the dial, the process is accelerated that much more due to the constant exposure to radiation. Also, if the watch is not water proof or water seeps in which may be the cause of the patina too.
