Using Ultraviolet Light to Make Nature Fluoresce in Photos
Ultraviolet photography is something that relatively few photographers explore, but it’s a fascinating realm to explore with less of an investment in equipment than most people think.
To clarify: There are two types of ultraviolet photography. UV reflectance and UV fluorescence. UV reflectance is using a light source that contains UV light (such as the sun or a full-spectrum light source) and collecting only the ultraviolet light that hits the camera sensor. This requires a camera modification similar to what you would do for infrared photography, but on the other end of the spectrum.
It can reveal hidden patterns in flowers that only insects can see, like a bulls-eye pattern in sunflowers and what effectively appears as a “landing strip” in many flowers to attract pollinators.
The bottom-right image above is made by collecting UV light. The bottom middle is visible light and the left is an infrared image of the same sunflower. While the dark pattern is certainly interesting, things become almost magical when you make the flower fluoresce (large image). UV fluorescence requires a regular unmodified camera, but careful attention to ensure only pure UV light hits the subject. If anything in the frame fluoresces, visible light bounces back to the camera.
Interestingly, just about everything in nature fluoresces to some degree. You may have heard about scorpions or certain millipedes glowing under UV light, but if you bring forward enough UV-only light, everything can “glow”. The intensity of the light is key, and it needs to be “pure” as even a fraction of a percentage of spill-over into the visible spectrum will contaminate your results.
This is a typical setup for an ultraviolet shot. Each of these Yongnuo 685 flashes has been modified to output exclusively UV light, and the process only takes about five minutes. You need to disassemble the flash (Warning: this is high voltage equipment you’re opening up. You can seriously hurt or kill yourself if the flash isn’t properly discharged and you touch the wrong components. If you’re unsure how to deal with equipment like this, give it to a professional.) and remove two pieces of plastic that are in front of the xenon flash tube. These control the flash beam but also block UV light.
There are two screws and a few clamps under the rubber circles on the sides of the flash, it’s not a complicated procedure. With these gone and the flash reassembled, you need to filter the light down to UV-only. I use a combination of two 77mm filters that do an awesome job: the Hoya U340 and the MidOpt BP365. Each of these filters on their own leak a very small portion of the visible spectrum; one leaks red, the other leaks violet. Together, they block it all. Conveniently, they also allow infrared light to pass through which the camera can’t see either, so they can serve multiple purposes.
The cost for each flash modification was around USD$500, so getting into this area of photography costs less than a good lens.
With three of these flashes at point-blank range at 100% output, the above image still needed to be shot at ISO 5000. Aphids being feasted on by a ladybug on a plum leaf never looked so bizarre. I’m unsure of the exact reason, but aphids and small spiders tend to fluoresce green.
Most insect eyes fluoresce blue, but flowers can contain many different colors — a yellow lady slipper orchid maintains its yellow “shoe”, but the ordinarily-green leaves glow red.
The key here is constant experimentation. Some flowers or insects are completely uninteresting in the way they fluoresce, while others are shockingly vibrant. It’s important to note that nothing can ever see the world this way — it requires that all visible light be filtered from the light source. Insects can see reflected UV, like this cicada image:
But when you photograph that same cicada in a dark room and collect the visible light? The clear wings turn into a science-fiction shade of glowing blue. The same is true for certain species of dragonflies, though most insects with smaller wings are unresponsive. Some research has been done into this and seems to link the elastomeric protein “resilin” and its nitrogen content to these glowing features but I’m shocked at the lack of scientific articles on the topic.
As a photographer (and not an entomologist or scientist in any way), I simply explore this unknown realm with childhood curiosity.
About the author: Don Komarechka is a nature, landscape, and macro photographer based in Barrie, Canada. His macro work has been highlighted in international publications. Don is an author, educator, and adventurer with a passion for revealing “the unseen world”. Visit his website here. You can also find more of his work on Facebook and Flickr.
