Portfolio: Documentary photographer Ed Thompson goes in search of ghosts in Kent

How do you photograph the invisible? It was a question Ed Thompson first pondered as a child when visiting the "most haunted village in Britain": Pluckley, in Kent. Pluckley is supposedly host to everything from a phantom monk to a ghostly highwayman – not that a seven-year-old Thompson, thermometer and camera in hand, managed to capture any paranormal activity. "Of course I failed. No ghosts," says Thompson. "But Pluckley was always in the back of my mind." And recently, he had the perfect excuse to visit again.

Now a documentary photographer, Thompson had got hold of some infrared film: "It stopped being made in 2010, and it's highly volatile. But this guy in Germany had some." Although expensive, unreliable and scarce – he managed to get only 23 rolls – Thompson loved the challenge. The Unseen Project was born.

Invented in 1910, and used primarily for medical, military and horticultural purposes, infrared has also long been popular with ghost-hunters. Humans can see a wavelength of light between 400 and 700 nanometres; infrared film records light between 750 to 1,000. "It's what you can't see, beyond our visual spectrum," says Thompson.

So it was the perfect medium for shooting Pluckley… "I want to believe," says Thompson, but he's quick to assert that The Unseen Project wasn't really about proving or disproving the existence of ghosts: "I'm more interested in folklore."

Good job: he didn't snap any spooks. But the colour-shift is genuinely eerie in itself; blood-red foliage is the stuff of horror movies, or a sci-fi disruption of cosy notions of England's green and pleasant lands. "OK, I didn't photograph any ghosts," Thompson accepts, "but [the images] are imbued with this strange psychological horror."

For more: eyestorm.com/edthompson