Got a question that has been bugging me for a few weeks. I got a UV flashlight to charge the lume on my watches before I go to bed. I noticed something odd on my Rolex Explorer from the early 2000s that has a SuperLuminova dial/hands. While it glows green (like I expect), it is distinctly a bright blue when under the UV light. See the attached pics. Every other watch I have with SuperLuminova Is the same green under the UV light as it is after I take it away. Only the Rolex is different.

I’ve searched but don’t see anyone else has noted this. Is this just a thing with these early Rolex SuperLuminova dials?

 

I found this article useful. I hope the link (below) works.

https://www.keepthetime.com/blog/super-luminova/

Photos from the link.

 

thanks. I know there are different colors of SuperLuminova, but my point was I have never seen one that glowed one color under UV light then another after exposed. Yes, there may be subtle differences, but on my Rolex dial it is a pretty stark difference. I assume they all did this, but I’ve never seen it mentioned anywhere.

 

I have just uploaded a video to YouTube that shows what I am talking about more clearly:

I’m showing my Speedmaster FOiS on the left, the Rolex on the right. First under UV light (sorry for the speck of dust), then with it off. You can see the abrupt transition on the Rolex when I switch the flashlight off.

 

The visible part of the light emitted by UV blacklights is blue, hence you get a blue cast when you use it, UV lamps differ too so some will look bluer than others. The colour that it glows once the UV is switched off is that of the SL lume, what you see before is a product of both the colour of the glow, and the blue visible part of the spectrum your torch or source emits. The video suggests simply that Rolex and Omega are using different SL formulations. Rolex would have you believe that it is their own special sauce. I am not persuaded by that myself, it is just a different colour.

 

Yes, I know the visible part of the UV is on the blue side of the spectrum, but why do all the other watches I have with green SL look green under it? Only guess is the Rolex SL was closer to the blue wavelengths of the spectrum, while the others are closer to pure green. Still a little surprised no one ever mentioned this before.

 

Is the lume on hte other watches you're looking at green under ambient light? May make a difference.

This also happens with the BB58 blue.

 

I had an EXP II once which dated back to the era of Donn's watch and it glowed in the exact same manner once when it was under a UV fluoro light whilst I was attending a function on a party boat.
It never happened again as far as I can ever recall but I didn't keep that watch for very long.
I put it down to the white pigment of the lume in combination of the specific band of light edited from that fluoro.
I have seen a similar phenomenon at a dance studio many years ago where there was one particular fluoro light on the ceiling that made the white straps of some girls underwear glow a bright violet colour when the other lights were turned off if their blouse was even fractionally sheer. I don't know what the material was on their underwear but it was obviously extremely white and it reacted to the frequency of the UV light. Perhaps it was Nylon
I suppose it may be similar to the old bank account passbooks with the signature of the account holder on the back page written in invisible ink. Whenever a withdrawal was made from the account, the bank teller would hold the passbook under what was called the "black light" to compare the signature in the passbook to the one on the withdrawal slip. Unless it was held under the black light, the signature was not visible but it would glow a bright violet colour.
Also specific fluoro lights over aquariums can enhance the colours of the fish despite glowing white to the naked eye or they can be a certain light frequency that makes the plants in the aquariums grow better.

Any way one looks at it, the particular light source is the common denominator with regard to what effects are observed.