Question on UV/Black Light test

[116710er]

So I decided to do a UV/Black Light test on a 40+ year old Sub. I've never done this on such an old dial and I was expect it to light up like my early 90's sub but the plots/hands seem completely dead. They don't glow or "glisten" under UV but rather show up as as pale white/greenish color under UV light (but it looks "flat"). Is this normal? My early 90's sub "glistens" when I hit it with UV. I'm assuming this is because even though it's dead to my eyes, it's actually still has some life (so something like NVG's might be able to pick it up).

Under a 10x loupe with UV, I can see a couple of specks here of there of brilliant neon orange on the 40+ year old dial.

[swish77]

Can you post some photos of what it looks like under UV? Your description sounds normal for old, dead tritium.

[watchmaker]

It is normal for old tritium to fluoresce under uv but will be dim and will decay shortly after the uv source is removed.

For a far more detailed description than I can give google 'hodinkee luminous dials'. They did a great article a couple of months ago covering Radium-tritium-luminova dials.

[saskmh]

Old tritium lume will have tiny specks glow under a UV light. But you can only see them under a loupe generally.

[R!$]

your 90s sub was WG surrounding the indices
Its normal...

[116710er]

Thanks for info. I'll try to snap some decent photos.I think my posts might have been poorly worded.

The 1990's 16610 glows under UV as expected. It's "dead" but under UV, it's lights up. As soon as the UV light goes away, it glows for a split second and they decays very quickly. Exactly as I expect it to react.

My question is really about my early 70's 1680. Matte dial, no WG surrounds. When I hit the dial with UV, the plots do not glow like my dead 16610. I'm assuming this is because it's much older but I've see photos where original 70's dials lume pot seem to glow similar to my 16610. This was my concern.

So far, what Saskmh is the only thing I can corroborate. Under UV light and a 10x loupe, I can see small micro-specs of orange in the lume plots (I'm talking only a few spots across all of the lume plots and hands combined.) My concern is that the lume plots were refinished some time ago with something like paint.

[Andad]

Could be impurities in the original mix.

[civic4982]

I’d also suspect that if the lume plots do not light up under UV then they possible have been repainted.

Any photos with normal light and with UV would help.


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[Rolexator]

It is perfectly normal for old Subs when only some particles glow while hitting the lume directly with UV-light.

Have you tried pointing the UV-light for 10 seconds or so to the dial and then turning it off and looking at the dial in a complete dark evironment? What did you see?

The whole lume (not only some particles) should glow greenish and very weak then and the glow should fade away pretty quickly (depending on how long you used the UV-light). The test while looking at it in complete darkness is crucial and not under direct UV-light because the glow on some of these old Subs is so weak that you won't see it under direct UV-light. You will only see it after removing the UV-light and looking at the lume in complete darkness, as I described before.

[swish77]

Several UV threads recently, but I'll post this photo again. Here's my 5512 (3.7 mil) with original tritium under UV. The tritium turns white, but is otherwise completely dead without the UV on it.

Maybe the OP could post some photos.

[saskmh]

I have macro photos of vintage dials with the "specks". I'll see if i can find them...

[116710er]

Sorry guy, I ended up sending the watch out before I could take picts of it. I'll post some when I get it back but that's for all the info.

@Swish77- So my old 16610 lights up like that under UV but my 1680 looks way, way more "muted". It looks more like the pip/pearl in your photo (maybe a little "brighter" than that but not by much.)

Here's the best pict (for now) that I have of the dial plots.

[116710er]

Originally Posted by swish77

Several UV threads recently, but I'll post this photo again. Here's my 5512 (3.7 mil) with original tritium under UV. The tritium turns white, but is otherwise completely dead without the UV on it.

Maybe the OP could post some photos.

Hey Swish, after looking at your pict again, I remembered that under UV, my plots look the same as the numbers/silver parts of the bezel insert. Same level of "glow" (or lack thereof)

[saskmh]

See the little flecks?

[116710er]

Hey saskmh, yes when I look through a 10x Loupe, I can see just like 1 or 2 orange flecks a couple of the plots. No green ones at all but I can't recall if I looked at every single plot. The "dead" parts of my plot look similar in color/glow as the plot you posted.

Usually when I see UV light test, I see that the plots are lit up a lot more than mine and more than yours. Yours is actually the closest to mine but yours has a few more glowing flecks.

[05carbondrz]

Originally Posted by saskmh

See the little flecks?

This is what mine look like too with little green and orange flecks/hairs.

[saskmh]

Originally Posted by 116710er

Hey saskmh, yes when I look through a 10x Loupe, I can see just like 1 or 2 orange flecks a couple of the plots. No green ones at all but I can't recall if I looked at every single plot. The "dead" parts of my plot look similar in color/glow as the plot you posted.

Usually when I see UV light test, I see that the plots are lit up a lot more than mine and more than yours. Yours is actually the closest to mine but yours has a few more glowing flecks.

Some have more flecks than others. This one was from 1968. My watches from the 80's have far less flecks...maybe three flecks on the entire watch. The lume mixes varied a lot over the years. The batches form the 60's were far better than the stuff they used in the 80's. Something else I've noticed is the flecks are often varied in colour. Some are greed, some yellow, some orange.

The other thing to note is that tritium is soluble in water. So if there was ever any humidity or moisture in the case the tritium usually dissolves pretty fast. I have one watch from the mid 80's with a perfect dial that still glows enough at night to read the time. Another that has had moisture in it... you cant see anything.

The UV/ fleck test is how I check dials to see if they are legit. If I really need to go further I have a friend that works in a radiation testing unit that can check radiation differences.

[Hollywoodvillain]

My 5513 ( 3.2 mil serial ) and my 16760 ( 8.4 mil serial ) look the same under a black light , they only glow while the light is on them and vanish immediately after removing UV light ! Ive never questioned the originality of the 16760 but would like to hear from some pros here wether or not I should be concerned ! Looks 100% original under loupe and has common issues for a dial of that era so re dial is not a concern , just want to verify that I’m not looking at a re Lume ! I can post pics if needed but I’m sure the question of wether or not a 16760 white gold surround indices dial Lume plots should glow under UV lighting can be answered without photos ! Thank you in advance !

[116710er]

Ok folks, finally got a UV pic of my 1680 and I think it's ok. When I look at the lume plots with a loupe using UV, I can see little green and orange flecks. Very sparse but definitely there. Let me know what you guys think. The thing that's throwing me off is that the silver portions of the bezel are bright (nearly "glowing") but the lume plots look so lifeless.

[linesiders]

Originally Posted by 116710er

Ok folks, finally got a UV pic of my 1680 and I think it's ok. When I look at the lume plots with a loupe using UV, I can see little green and orange flecks. Very sparse but definitely there. Let me know what you guys think. The thing that's throwing me off is that the silver portions of the bezel are bright (nearly "glowing") but the lume plots look so lifeless.

No worries re; Insert -v- Plots. Different items altogether.

Different lumes react differently, even different tritium mixes from the 60s and 70s have different variations.

PS - love the Puff shirt

[116710er]

Originally Posted by linesiders

PS - love the Puff shirt

[Tillie]

Sorry for replying to an old thread. My old Cosmograph from the early 70’s glows wonderfully under black light . Once the light is removed it sadly fades away fast. The color is a beautiful greenish tint.

[springer]

Originally Posted by Tillie

Sorry for replying to an old thread. My old Cosmograph from the early 70’s glows wonderfully under black light . Once the light is removed it sadly fades away fast. The color is a beautiful greenish tint.

Sounds 100% correct for an early 1970s Daytona.