Fluorescent night dives (or “fluo diving” for short) are also known as “fluoro dives” or “glow dives”. It’s what happens when night diving with underwater torches that emit fluorescent light. They have grown increasingly popular in recent years because of the widespread appreciation of the nocturnal sea. More and more dive clubs offer fluo diving, and more and more vendors selling torches necessary equipment appear on the market.
A better understanding of the background and basics allows making more of this exhilarating experience. Some people say that fluo diving is like being in the movie “Avatar”.
Here you can experience the amazing Fluo Diving:
Why does this happen
Schematic of fluorescence
Fluorescence is the physical effect shown by some materials when they absorb high-energy (and therefore short wavelengths) and to re-emit light of lower energy (and therefore longer wavelengths). Check out the schematic picture.
Other sources of energy may also cause the same effect, such as for example high-speed electrons in cathode ray tubes.
This phenomenon not only occurs in living organisms but also in minerals. “Fluorite” or “fluorspar” is the crystalized rock form of calcium fluoride and is also the mineral that gave this effect its name. When heated this material generates thermoluminescence, thus creating the “fluorite phosphorescent effect” we recognize as glow-in-the-dark.
Learn more about fluorescence
Fluorescence should not be confused with phosphorescence that you know from your dive tech or glow-in-the-dark toys. Phosphorescence has the capability to store light, and re-emit it over a longer period of time, which is therefore not the same.
Steffen Beyer
The phosphor coating on the inside of cathode ray tubes and fluorescent tubes (neon lamps) provides both fluorescence as well as phosphorescence (the familiar afterglow).
This is also why you will find an option “fluorescent light” under the white balance menu in your digital camera. This is not the correct setting for underwater fluorescence photography and filming, though! More on that in a later article on Fluorescence Night Diving!
Have you ever experienced Fluorescence Night Diving? What do you think about it? Leave a comment below!
Looks like a very cool night dive. Can you recommend dive spots where this is more likely to happen?
Would love to see it.
I mostly dive in europe, but once or twice a year I’ll end up in asia for some diving too
Dear Neal,
any tropical waters will do, even cold waters, to some degree; see e.g. https://www.firedivegear.com/gallery/videos/?5. Southeast Asia is actually famous for its fluorescence (see e.g. the Wakatobi Dive Resort).
Good luck!
Buddy Dive Resort in Bonaire offers this night dive as well. I did the dive with my wife. I loved it and she hated it! The difference? Due to the shape of my mask I had a tiny portion on the lower part of the normal mask lens where I could see the reef more “normally” without looking through the applied fluorenscence visor that fits over your mask. Without that little “slice” of normal lens, the visor is pretty dark and my wife said she felt totally blind. (Secretly though, I think the 6 or 8, two-meter tarpon darting around everywhere helped freak her out! They love the UV light for hunting!)
It’s a fun dive and a brand new way to look at the reef!
This is something I have to try out! It looks absolutely amazing! I tried a lot in diving, but I never heard about this!
Did you put the UV lens over the camera to film this video?
Great video!
Dear Jim,
first of all thanks a lot for the kudos;
I’m glad you liked the video!
To your question: Things are a little bit more complicated than that.
There is no UV involved, but blue light, and there has to be a (blue pass) filter on the blue light torch to “trim” its light output in terms of its wavelength distribution. Moreover, the camera needs to have a yellow (blue block) filter on, in order to filter out any reflected blue light and to let only the fluorescence pass through, which filter has to be complementary to the filter used on the torch.
Dear Jessi,
I am glad you found this article inspiring!
Good luck and lots of fun trying this out!
Hi Jim!
I just came back from Bonaire where I rented the truck, tanks and weights from Buddy Divers.