Tritium lume

[shammad10]

Sorry for another post!
Just wondered what you would expect to see from old tritium lume that’s >30 years old under a UV light? Would you expect to see any reaction at all? Or would you see nothing as it would be degraded by now?
Thanks

[lupus66]

depends. full reaction, spickles, nothing.

[linesiders]

Everywhere from a glow seen from space to nothing at all. The compounds used in Tritium Lume were always changing, even same year watches can have different compounds.

[shammad10]

Okay thanks. Would you expect all the indices to have the same amount of degradation? It would be unusual to have some speckles and some not?

[lupus66]

yes same degradation

[springer]

This was discussed in an earlier thread a couple weeks ago. I can't find that thread but it is here somewhere in the Vintage Forum.

Regarding your question, after 1967, most of the lume on sport models look white under UV. They do not glow when the light is off. Some of the models, like Daytonas, Datejusts and some others still have the older tritium that glows green under UV and will glow green for a few seconds or longer once the light is shut off.

In most cases, if it looks flat brown under UV, it has probably been relumed.

(In the photo below of the 1967 GMT, the lume at the 12, 1 and 2 markers appears to be a lighter green when compared to the other markers. This is due to the positioning of the UV light directly above this area. Factually, all the lume is the same color under UV if the light is moved to a different position above the dial.)

The same principles that apply to dials also apply to the hands.

[shammad10]

Originally Posted by springer

This was discussed in an earlier thread a couple weeks ago. I can't find that thread but it is here somewhere in the Vintage Forum.

Regaerding your question, after 1967, most of the lume on sport models look white under UV. They do not glow when the light is off. Some of the models, like Daytonas, Datejusts and some others still have the older tritium that glows green under UV and will glow green for a few seconds or longer once the light is shut off.

If it looks brown under UV, it has probably been relumed.

(In the photo below of the 1967 GMT, the lume at the 12, 1 and 2 markers appears to be a lighter green when compared to the other markers. This is due to the positioning of the UV light directly above this area. Factually, all the lume is the same color under UV if the light is moved to a different position above the dial.)

Thanks, that’s great info.
I saw a watch today under UV where all the indices and hands had a few speckles of green- other than the second hand, which had a fair few more speckles of red!! why the difference in colour?

[springer]

Originally Posted by shammad10

Thanks, that’s great info.
I saw a watch today under UV where all the indices and hands had a few speckles of green- other than the second hand, which had a fair few more speckles of red!! why the difference in colour?

I would need photos to see what you are referring to.

The older dials where the lume looks green under a UV light will tend to have a sparkler affect under UV and is usually observed best with a magnifying glass.

[adawil2002]

After 35+ years my 16550 may last 30 minutes then dims to almost nothing.

[springer]

Originally Posted by adawil2002

After 35+ years my 16550 may last 30 minutes then dims to almost nothing.

I've never heard of an original watch from 1986 where the tritium lume still glows after 30 minutes let alone 30 seconds. I've owned dozens of Rolex from 1980 until 1990 and none of mine glowed like your watch.

That must be some special type of lume on that dial!

[Dan S]

Originally Posted by springer

I've never heard of an original watch from 1987 where the tritium lume still glows after 30 minutes let alone 30 seconds.

That must be some special type of lume on that dial!

FIFY, JP. Happy New Year!

And you're right of course. I just tested a 1991 Sub, very faint glow for about 10s after UV excitation.

[KY..]

Originally Posted by springer

This was discussed in an earlier thread a couple weeks ago. I can't find that thread but it is here somewhere in the Vintage Forum.

Here’s the reference link for tritium lume.
https://www.rolexforums.com/showthread.php?t=123465

[shammad10]

Originally Posted by KY..

Here’s the reference link for tritium lume.
https://www.rolexforums.com/showthread.php?t=123465

Thanks for that- really interesting read!!