In the summer of 1991, photographer Zed Nelson, then 25, invited a couple of new parents he was acquainted with to visit his London studio. Oh, and bring your baby, he said. At the time he had ambitions to be a travelling photojournalist. Within the year, he would fly out on the first of a series of visits to far-flung conflict zones. But for this, Nelson had in mind a quieter, more domestic project. He set up a backdrop and lights, and he encouraged the visiting parents – a personable couple called Sue and Frank whom he’d met at a party – to pose with their newborn, Eddie. The parents held hands, wild-eyed, visibly shot through with the terror and excitement of parenthood. Eddie, weeks old, oblivious, considered his own fingers and dribbled. It might have been any other family portrait. Except that Nelson invited Sue, Frank and Eddie back to his studio for more portraits, at the same time of year, every year, for as long as they agreed to come. He would chart the evolution of a parenting life, with Sue fixed in position on the right of the picture, Frank on the left, Eddie inching up between his mum and dad. “Same backdrop every year, same lights, same camera, same angle,” Nelson explains, thinking back over the finicky logistics of a project that has run since 1991 without interruption. “Every year I measure out the distances to the inch. It drives us all a bit mad. But we do keep coming back.” During the first few years of this project, which Nelson calls The Family, the photographer’s own life was eventful and stressful. On commission abroad, he would follow dictators and document famines, all the while aware that this regular portrait session was an anchoring date on his calendar. He once invited Sue and Frank for their annual sitting when he was just off a plane from Angola and shaky with malaria. “I liked the reassuring continuity of it,” Nelson says. In 2010, the Guardian published images from the first two decades, showing Sue and Frank’s progress from junior parents (aged 36) to empty-nesters (aged 55). At the time, the family felt too shy to speak about it. They had barely admitted to anyone that this was something they did. Sue works as an artist, Frank as a teacher-support. They’re private people; when the images appeared in print, colleagues and friends were astonished. People would ask the reticent couple: “Is this really you?” “Neither of us had any idea that it would go on so long,” says Sue, on the phone from the family home. She and Frank have agreed to share their views on this priceless, singular record of their adult lives. “When we started, it was a pre-digital era, pre-internet,” says Frank, “and we didn’t give any thought to what would happen in the future. There’s no way, all those years ago, we would have asked ourselves: ‘What will this all look like in 2021?’” When Sue looks back at the very earliest photograph in Nelson’s selection, which shows Eddie in his car seat, she remembers the intense sensation of parental duty. “When you first have a child, you think it’s going to go on for ever, just because of that intensity,” Sue says. “Actually, the three decades since then have gone in a flash. Like a movie on fast forward. These photos make me realise the sheer speed of time passing.” Her son’s teenage years seemed especially, cruelly swift. “Eddie started secondary school one day, and boof – next thing we knew he was a man.” In the photograph taken when Eddie was 12, Sue and Frank have tilted heads. It’s as though they’re being buffeted by the tailwinds of their son’s dramatic growth spurt. At 14, Eddie is almost the height of his father. At 17 he’s a smidgen taller. At 18 it’s no contest. “He’s a complete, free-standing individual who doesn’t need us,” Sue notes. “And though there’s a sadness attached to that for me, there’s also a great joy and pride.” It was around this time, as Eddie prepared to go to university in the late 00s, that Nelson presented the family with a portfolio of the photos he’d taken so far. Previously, they had never seen more than the odd Polaroid from the previous year’s sitting to help orient themselves. “Zed didn’t want us looking at the photos and making plans for next time,” Frank remembers. He never wanted us to dress up. What I think he was trying to avoid was that annual-family-photograph feeling. He would often tell me not to smile. He would order me not to suck in my stomach. This might sound odd, but I always felt slightly removed from the whole process. I felt we were models and simply illustrating something.” Sue agrees. She remembers receiving the first photos and feeling estrangement from the figures in them. She still feels like that. “There’s a feeling that we’re characters in a plot. I’m looking at people ageing, Eddie growing, and I think, ‘Who are they?’ I don’t always see us in them. They don’t entirely look like we do. Another artist is making the choices. It’s his project. They represent a story about change, about ageing, not a story about our personal lives or about us and who we were at that time.” Perhaps the images are a canvas on which we project our own experiences and expectations. As a father on the brink of 40, I find myself particularly fascinated by the story that appears to play out in Frank’s face and posture as his son outgrows him. Eddie becomes the vigorous, more handsome, healthier man, almost displacing Frank. He starts to throw his shoulders back and stare into a future somewhere beyond Nelson’s camera. To the side, Frank seems to sink in on himself. He loses weight. The face turns leathery. When his son is 23, and Frank is about to be 60, he appears to commit to a new, nattier wardrobe. Suddenly dapper in waistcoat and tailored shirt, the spectacles fashionably thicker, Frank seems more at ease again. It’s as though the passage in and out of some mild midlife crisis has been captured. But these are only my impressions, based on Nelson’s selection from hundreds of reels of photographs. “I can’t really remember one of those years from the next,” Frank says cheerfully, thinking over the period I’ve interpreted as one of collapse and renewal. “I’m not very sentimental. I tend not to look back at things. I’m most interested in the day in front of me… Obviously, as one gets older, I do have some thoughts about the passing of time. Sue and I are both 66 now. These days, 60-odd seems quite young. But I do have a growing sense that it isn’t going to last very much longer.” Eddie was always a willing subject for Nelson’s photographs, but he prefers not to be interviewed. Instead I get to know him as a changing figure in the photographs, the student years sloughing off him as he broadens, gyms up, his fringe beginning to retreat and reveal a rounded forehead like his father’s. Eventually, “Eddie’s almost pushing us out of the frame,” Sue notes. “If you want to read the photographs in this way, you could say we only had one son, and that is a very close relationship, but we’ve had to learn to give him room. As he grows and changes, so does our role in his life. We have to stand back.” In the later photographs, Sue continues switching up her outfit and hair colour, as she’s always done, reinventing herself. For a long stretch she seems to age subtly, almost invisibly. She remembers, “There were some years we posed for the photographs and I wondered, ‘Do I want to see myself getting older? Do I want others to see that?’ A vanity thing.” In 2016, she has ruffled, bleached hair and stares down the camera more punkishly and defiantly than in any other photograph, as if daring it to capture her ageing. Then, abruptly –it’s the same year her baby boy grows a beard – Sue looks markedly older. She drops the patterned clothes for stately, sombre dresses. In the 29th photograph she seems to have accepted some new interesting phase is imminent. “I have to say,” Sue says, “I’m not ageing in quite the same way inside my head. I don’t feel as though I’m ageing at all, really, because I’m not faced with it every day. My mind works how it always has. I don’t think of myself as getting old, I think of myself as having gone on this incredible journey, still doing things, feeling, thinking, making stuff. I feel proud that Frank and I have come so far as a couple and as parents, and we’re still able to do the things we enjoy. That’s why I have to detach myself from these photographs a bit. Because for me, I don’t see myself in decline. I see myself forever reaching up to do more.” In the final photograph, taken by 56-year-old Nelson this year, Eddie is 30. He has a partner of his own and a baby daughter. For the first time in years, Frank is smiling. He clutches a toy dinosaur as though ready to leap in at any moment and pacify his granddaughter. Sue is slightly slumped, as though she’s been reminded once more of that intense parental responsibility. Eddie’s hands are locked tight around his child. The baby has eyes on Mum. “And the cycle begins again,” sighs Frank. They have all wondered, occasionally, how this project might end. Frank says: “It would visually make sense if… Well, I suppose, if one of us, or both of us… ” He trails off. “It’s not a very appetising thought.” He wonders if, deep down, he, Sue and Eddie have always kept this careful distance from Nelson’s project because they can envisage how it must end one day. Very likely there will be a photograph with one person missing, then two, and Eddie will be without his parents on that familiar backdrop. “Scanning 30 years of your own life, it certainly stirs up feelings of mortality,” says Frank. “But I suppose we’ll just keep going with the photographs for as long as we can, till one or both of us falls by the wayside. Zed’s a lot older than Eddie. So either way,” Frank says, “it’s not going to go on for ever.”