yet another LUME question...

[mgm]

I think I get the different types of lume

The question: My watch dial, serviced last at RSC, states T<25. It illuminates after exposure to light and dulls down in the dark. It's very noticeable when the dial is half exposed and half not... you can clearly see only half the dial. My understanding is that only L/SL do that. But I must have it wrong?

[mike]

It's possible that the light is causing a reaction to the phosphors in the paint matrix. It's been known to happen with T<25 dials. Doesn't last long at all.

Tritium dials are composed of:

1. Tritium--a mildly radioactive substance that causes the
2. Phosphors to excite--the part that glows (tritium in and of itself does not glow and,
3. The bonding agent--the stuff that holds everything together--about 90% of what you see.

[Art161]

I am so glad that this question was asked and answered. I thought I would be ridiculed no end if I posted that the watch I purchased in 1971 glows with great brilliance only if exposed to strong light before being taken into a dark room. Absolutely true--the lume only lasts a few minutes.

I may still be ridiculed, but at least not for this.

[mgm]

Thanks for the reply, Mike! I kept going back to the threads and articles on lume...

Art...

[Z-Sub]

Originally Posted by mike

It's possible that the light is causing a reaction to the phosphors in the paint matrix. It's been known to happen with T<25 dials. Doesn't last long at all.

Tritium dials are composed of:

1. Tritium--a mildly radioactive substance that causes the
2. Phosphors to excite--the part that glows (tritium in and of itself does not glow and,
3. The bonding agent--the stuff that holds everything together--about 90% of what you see.

x2
At least Your phosphour is still working properly without the radioactivity from tritium.

[Andad]

Here's some 'L' lume.