I'm sure this has probably been asked before but I did a search and didn't find any threads on it.

What are the pros and cons of LumiNova hands and dials versus Tritium?
And why did Omega switch to the LumiNova?

Also, what were the pros and cons of Radium in the vintage watches?
I know it was low-level radioactive, but anything else about its characteristics?

Thanks, I'm not very knowledgeable about this topic so even basic information is appreciated.

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Radium has a huge half life but is quite nasty stuff but the zinc it reacts with breaks down in time. Tritium only has a half life of about 12 years so loses its glow. Luminova is not radioactive and is charged with UV light and doesn't decay like the above. It is safe and glows for longer than tritium.

 

Is Tritium more desirable in a watch than LumiNova? Or the other way around?

 

Luminova and now Super Luminova do not use radioactive sources like radium or tritium. You can still buy tritium watches but it is encapsulated in tubes. People like vintage tritium because of the shades of brown that it turns over time. Typically it only lasts for 10 years so it’s not as useful as modern lume watches that use super luminova which last longer and are safer for all involved.

 

Is it possible to get Tritium “re-energized”? Can its original degree of brightness in the dark be restored?

It would be great if you could put it in the microwave for 30 seconds and it would restore it.

My 145-022-68-ST was made in July 1969 so the Tritium in it would be 1/16th its original brightness (assuming a 12 year half-life over 51 years).

 

As I understand it, and perhaps one of our members who is more knowledgeable could expand, that isn't quite the case. The amount of light emitted isn't just a function of how radioactive the tritium is, but how much the phosphorescent material has been degraded by the tritium over the years. When I was first learning about this, I found this article helpful, and I think it answers all the questions you have posed:

https://www.hodinkee.com/articles/l...s-them-glow-and-how-to-spot-their-differences

 

@Stripey is spot on. Unlike in cartoons, radioactive materials don’t glow. (Well, unless they are going critical, then you have a much larger problem.) The materials the radioisotope is mixed with get excited by the radioactivity and emit light. Those materials break down over time and the paint changes color. Tritium’s MUCH shorter 1/2 life just means it is also degrading relatively quickly.

Radium has a 1,600 year half-life, so that 1920 watch with the radium dial is virtually as radioactive as the day it was made.

Super-luminova is superior, IMHO, at getting the job done safely. It definitely lasts and continues working better than Tritium excited paints, at least in my experience. My tritium dials have faded noticeably, my SuperLumiNova dials of similar age are still bright. How long it will last is anyone’s guess.

The obvious advantage of tritium or radium is that they don’t need to be charged with light. A NEW tritium or radium dial would shine for years if the sun went out. A new tritium dial will glow great for 5 or 6 years, but by 12 it’s only half as bright. I’ve had to replace the tritium sights on several handguns over the years.

Edit: spelling error and changing last paragraph to stress that a NEW tritium or radium dial would keep shining if the sun went out. The time factor still plays. And you can't get a new radium dial unless you have a DeLorean and a flux capacitor.

 

This thread went quite into detail regarding tritium:

https://omegaforums.net/threads/tritium-decay-rates.114242/#post-1514721

 

I have a Germany marked Elgin that has very bright long lasting lume. No clue as to how old the watch is other than its 50-60's styling.
I suspect the dial is a service dial.
Problem with it is that several of the lume dots on the dial have become detached and can be seen stuck under the edge of the crystal.

I also have a cheap refurbed redialed Fortis which is uncommonly accurate.
The hands have good lume but the markers of the black dial have no lume at all.
Are there any good sources for fairly easily applied lume dots, 1/16" or smaller? Super luminova if available , and hands for various applications.