Picture the scene. A baking hot day. Bright sunshine. Deep, dark shadows. The sort of day that colour photography just doesn’t work, so instead you shoot black and white. Or even better, you shoot infrared black and white. Infrared-adapted cameras love bright, harsh sunlight. The sort of light that leaves you peering at the world even through darkly tinted sunglasses.

Of course on a day like that you never want to be too far from an air-conditioned café, so the best option is the city, right? Yes, the asphalt stores the day’s heat, there are too many people, and the buses all grind to a standstill. But at least the Place to Eat at John Lewis is cool, and you can find a quiet corner to regain your composure and plan the next set of photos.

That’s how it was on an August day in 2022 when I visited Old Calton Burial Ground, at the eastern end of Princes Street, Edinburgh, to photograph the cemetery’s historic tombs and lairs. Infrared cameras love cemeteries almost as much as they love harsh summer sun. Despite the familiar surroundings I was finding new angles, new compositions, new ways of seeing.

Even in daylight, most visitors to Old Calton Burial Ground stick to the highlights: David Hume’s Mausoleum, the Political Martyrs’ Monument, The Abraham Lincoln Memorial, and the views on Calton Hill and Salisbury Crags.

Step beyond those, ignoring the slight sense of menace even on this bright sun-drenched day, and you’ll come to the Robert Burn Mausoleum. On the day I visited, the mausoleum was unsecured, and I took the opportunity to photograph the open doorway. Only when I got home did I see the bedding on the floor and, to my shock, the legs of a homeless man sleeping away the hottest part of the day, hiding from the sun.

If I had noticed I would never have pressed the shutter. Photographing street candids is one thing. Photographing people experiencing homelessness is a step beyond – only to be undertaken in the course of serious journalism or documentary.

Having taken the photo I kept it private for a long while, trying to decide whether I could share it. And now here it is. What would you have done?