I'm standing in a shed in a back garden in Duddingston with Robert Burns, the now sadly deceased singer Michael Marra and Tretchikoff's Green Lady.

No, this is not the start of a bad joke. It's actually the beginning – or probably the middle – of two new works of art.

They are down to the other man in the room, Calum Colvin. It's his back garden. It's his shed – or studio, to give it its proper title. And the installations of Burns and Marra and the Green Lady will be part of his latest exhibition (if he gets them finished on time). It's in this space that he builds his sculptural installations that riff on such subjects as Scottishness, pop culture, the things we discard (Burns's eye is painted onto an old salvaged globe). And it's where he takes the photographs that are the final part of the process, photographs that are, in the end, the artwork.

All three of his studio "guests" have a personal resonance for him. Colvin knew and liked Marra for years. The artist Tretchikoff loomed large in his childhood imagination because he seemed to Colvin to be the most successful artist in the world, "because everybody had Tretchikoff in Scotland in the 1960s". And as for Burns... Well, he's Robert Burns, a constant in Colvin's work and a signifier – perhaps the signifier – of Scottishness. "There are very few figures who remain at that level internationally. Like Elvis Presley. But Burns is up there, which is an amazing thing given how short his life and how long ago it was."

In the world of art, Colvin, now 51, is himself a signifier of Scottishness. There are few contemporary artists who have been so engaged in the ambiguities and ambivalences of Scottish culture and Scottish identity. For near enough 30 years his photography has explored the history of his native land, the kitschification of its culture and the myths it tells itself from tartan to Ossian.

Indeed, it was the unveiling of the controversial anatomical recreation of Burns's head at the start of this year that inspired some of the work in his current exhibition Burnsiana at the Robert Burns Birthplace Museum. Because it turned out "he wasn't the Burns people thought," says Colvin.

"That made me think about familiarity. It didn't look like the paintings. I thought 'he looks like a Scottish farmer' – which he was – rather than the rarefied, romantic, fine-featured image that we're used to."

I first came across Colvin's work in the late eighties when he was illustrating the odd cover for Stiff Records (I had a copy of Furniture's 1986 album The Wrong People, graced by a Colvin photograph). Colvin did record covers for Stiff supremo Dave Robinson. "He was quite a character." So the legend suggests. Did Colvin get paid? "I did, yeah. I used to meet The Pogues in the pub and they were never paid and when Stiff went under they lost money."

At that point Colvin's career was climbing the charts. He'd not long graduated from the Royal College of Art and was exhibiting at the Photographers Gallery in London straight off the bat. Soon he was travelling to the States and establishing himself as a new – and very Scottish – voice in British art.

"I was always interested in the idea of being Scottish, being from this little country that didn't even have its own parliament in a wee tucked-away corner of the UK. But I was also interested in the idea people had of Scotland, which people in England could never understand. They could never understand the global reach of Scotland. They would say, 'they won't know the terms of reference of the work you make'. And I would say, 'no, they will', because I was referring to historical aspects of Scotland's culture. I would say 'most countries have a sense of national identity. They have a sense of asserting identity, sometimes in adversity. But they also have a concept of Scotland itself. It might be tied to Brigadoon, whisky labels or golf, but at least you've got an in, you've got an imaginative world to play with."

He has been playing in that imaginative world, enlarging it, rendering it ever more three-dimensional (or as 3D as photography will allow) ever since. You could, say for the purposes of an interview, frame his story as a Scottish story (though it's also a photography story, an art story and, evident from the children's toys that surround us as we sit chatting in his house, a human story).

He grew up in Gullane in East Lothian (once the family had stopped moving around) and in a country where kids sewed badges onto their jeans proclaiming they were "Scottish and proud", where girls wore tartan in honour of the Bay City Rollers, what he calls a "cheesy" Scotland, an Irn-Bru conception of place. He'd see the historical novelist Nigel Tranter jogging on the local beach. "Never read his books. They looked like trash to me. Still haven't. They're probably very good."

But Colvin also grew up a political animal. His father was active in politics and Colvin was a Labour supporter. "I think we all subscribed to a notion of Britishness that was tied very much to the notion of the Labour party," he says. Tony Blair did for that, he reckons.

"I felt very Scottish myself and it wasn't really an issue in my work until I went to London and I had such a strong accent people couldn't understand anything I said. And then people would say 'well, you Scots are like this.' And I used to think 'are we?' So it's only really when people kept throwing it back at you that you began to think about it."

The idea of being an artist had lodged itself early. "I wanted to be a cartoonist when I was 10. I always knew art in some form was a route I'd go along."

Nobody had gone to art school from his school in North Berwick but in 1979, at the age of 17, he left for the Dundee School of Art, where he now teaches. "Art school was in certain senses the beginning of my life. It was a journey that I'm still on."

He'd gone to Dundee with the idea of being a landscape painter, but after a year the idea paled. He left the painting department (for years afterwards, every time he saw the artist Albert Morocco, who was head of department, Morocco would glare at him for the audacity), switched to sculpture and as a subsidiary signed up for photography. His tutor Joseph McKenzie gave him a camera, told him to go out and take some photographs. "I remember the first picture I took. It was a picture of a little Mod scooter with all the mirrors. And the light was hitting it on a cobbled street in Dundee. And I remember thinking 'this is just great'.

Colvin became obsessed. He would wander around Dundee, a city then half derelict, poking about its abandoned buildings and take photographs. For a while he tried to insert photographs into his sculptures. But when that didn't really work he opted for the negative of that, inserting the sculpture into photographs. He'd arrived at his style. In London he started using colour photography and the Colvin vision – a mix of super-dense imagery in super-saturated colours – began to emerge.

He'd gone to London in the early eighties because he didn't feel there was much in Scotland for him. He returned here at the start of the nineties when his then wife was pregnant. "I also felt that if you make work about Scotland it's quite good to be at the source of your inspiration."

Photography and Scotland are the two poles he circles around. He talks about the ambiguity of photography and then extends that idea to Scotland itself. It's as if the country he was raised in was out of focus. "I grew up in a country with no real parliament, with a strong sense of itself, but no say in its own future. Now we just have a wee say. People think that's enough."

It is fairly obvious, he thinks, how he's going to vote in next year's referendum. "I'm very much for a Yes vote. I think it's a bit unfortunate that we only concentrate on the economic argument because I think it is so ambivalent. I also think if Scotland was such a drain on the UK's resources it would have been independent years ago."

It's the fact that we have no control over who we go to war with or whether or not nuclear weapons are held on our soil that bothers him. "Scottish solutions to Scottish problems. To me it's a no-brainer." That said, he's not optimistic that there will be a Yes vote. "I hope I'm wrong."

In the meantime he works away, lectures, looks after his three-year-old daughter (he has three other children from an earlier marriage) and is relaxing into the second half of his life. "There's never enough time and I used to get anxious about that. I'm a thrawn Scottish Protestant. I believe in the work ethic. But I'm relaxing a little more about that."

I leave him to head out to his studio again, to continue think-ing about Scotland, its myths and stories, its sense of self. It's what he knows best. He's made an art of it.

Burnsiana at the Robert Burns Birthplace Museum continues until September 15.