Ultraviolet photography

Ultraviolet sits on the opposite side of visible light from infrared, just past violet. It splits photography into two very different techniques, and the results are some of the strangest in the whole spectrum.

Two techniques

Reflected UV. The camera records ultraviolet bouncing off the subject. You put a UV-pass filter on the lens that blocks visible and infrared light, and you need a UV-rich source: sunlight, a xenon flash, or a 365nm lamp. Many ordinary lenses pass some UV, but dedicated quartz lenses such as the UV-Nikkor do it far better (Kolari).

UV-induced visible fluorescence (UVIVF). You light the subject with UV in a dark room. The subject absorbs the UV and re-emits it as visible light, so it appears to glow. Here the camera records the visible glow coming from the subject itself, through a filter that blocks the UV (National Geographic, Craig Burrows).

What glows

Under UV, a surprising range of things fluoresce: many minerals, scorpions, tonic water (from the quinine in it), highlighter ink, the optical brighteners in white clothing and paper, teeth, and some flowers. A dark room and a 365nm light are most of what you need to start.

The flower trick, and the honest version

Bees see ultraviolet and we do not (we trade it for better red vision). Many flowers carry a UV “bull’s-eye,” a UV-absorbing center ringed by UV-reflecting petals, and it is the most prominent UV pattern flowers show. A field experiment found flowers with the bull’s-eye drew more visits from bees and flies than flowers without it (Lunau 2025, Koski & Ashman 2014).

The honest caveat: ultraviolet is just one channel of insect color vision, not a separate secret signal beamed only to bees. The bull’s-eye is not universal across flowers, and the same study found it boosted visits without clearly steering bees once they arrived. Still a real and beautiful cue, just not magic.

Other results

Sunscreen looks black in reflected UV because it absorbs ultraviolet, which is why UV photography reveals sun damage and freckles the eye cannot see. The same sensitivity is used in forensics and to check the security features printed on banknotes.

Safety

Ultraviolet can harm your eyes and skin. Never look into a UV source or shine a UV torch toward anyone’s eyes, wear UV-blocking glasses while you work, and never look through a UV-pass filter at a UV light. A 365nm torch is “purer” ultraviolet; a 395nm one spills a fair amount of visible purple (Kolari).

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New to the spectrum? See the basics.