New to me Speedy

rootbeer7 · Mar 21, 2020

Just got this Speedy. Approx 1997 by serial number. It still glows slightly after being in bright light. I just wanted to check this is ok for a late tritium. Many thanks in advance.

OMEGuy · Mar 21, 2020

The dial looks fine. I'm not sure about the hands, because the picture is not good enough.

Generally it is ok that the tritium isn't very active anymore on a watch of this period.

rootbeer7 · Mar 21, 2020

OMEGuy
The dial looks fine. I'm not sure about the hands, because the picture is not good enough.

Generally it is ok that the tritium isn't very active anymore on a watch of this period.

Thanks so much for your reply. I thought lume would be dead, but I now realise that a little glow for a short period is correct.

SamH · Mar 21, 2020

Far as I know (someone correct me if I'm wrong) the tritium kept the lume charged in a sort of hybrid arrangement (as opposed to glowing radium for example), otherwise the rest of the lume has a short photoluminescent effect. Older tritium watches I've got can usually get a few minutes of glow going after bright light exposure. Seems to vary in lasting effect from one to another though.

rootbeer7 · Mar 21, 2020

S SamH
Far as I know (someone correct me if I'm wrong) the tritium kept the lume charged in a sort of hybrid arrangement (as opposed to glowing radium for example), otherwise the rest of the lume has a short photoluminescent effect. Older tritium watches I've got can usually get a few minutes of glow going after bright light exposure. Seems to vary in lasting effect from one to another though.

Thanks very much for your reply.

padders · Mar 21, 2020

S SamH
Far as I know (someone correct me if I'm wrong) the tritium kept the lume charged in a sort of hybrid arrangement (as opposed to glowing radium for example), otherwise the rest of the lume has a short photoluminescent effect. Older tritium watches I've got can usually get a few minutes of glow going after bright light exposure. Seems to vary in lasting effect from one to another though.

Not really no. Tritium lume worked exactly the same way as Radium lume. A radioactive component is used to constantly excite a phosphorescent component, usually Zinc Sulphide. With Radium, the ZnS degrades and fails under intense bombardment, with Tritium lume, the radiation decays away as the half life of tritium is only 12.5 years and the lume becomes inactive. Even the youngest tritium watch lume has only 1/4 to 1/8 of the radioactive energy it had when applied. It thus becomes near invisible to the human eye. The few mins of glow you refer to when tritium lume is excited by UV etc is the short lived glowing of Zinc Sulphide component which is phosphorescent but not persistent. Modern Superluminova works very differently with no need for radioactive stimulus and does not lose potency appreciably over time.

SamH · Mar 21, 2020

padders
Not really no.

Cheers for clarifying that - I was under the impression that radium actually did emit the glow, whilst lower radioactive levels from tritium charged the phosphorescent paint. I think it's based on the time we ran a geiger counter over older watches at school (late 80's). I don't know if the hollywood glowing radiation depictions fed into it, but I wouldn't be surprised.

New to me Speedy

rootbeer7

OMEGuy

rootbeer7

SamH

rootbeer7

padders

SamH

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