It's 1964, somewhere amid the oily bustle and clank of the Cork docks, and the lens locks onto a rusty old tanker. Sitting on the deck is a pretty young lady with a toppling beehive. She's sporting leopardskin print pants and a disdainful air as she listens to the patter of a skinny character with a greasy quiff. Maybe, in the local parlance, he is applying the hard word.

Loop forward 20-odd years, and here's a bunch of 1980s Cork teenagers. They are clad in vast swathes of stonewashed denim. Their jeans are rolled up to reveal glittering expanses of white socks. They've got Nik Kershaw haircuts. They're holding placards that read "We Want Jobs!"

These are just a couple of the images from Fiens And Buores, a photography exhibition at the Crawford Municipal Gallery that documents the past 50 years as experienced by the young in Cork. You can gauge the social turmoils, and the ever-changing moods, but the most fun is in sifting through the capricious definitions of cool, working out how they shift and twist as the decades turn.

Happily, wandering about the show, I am in the company of a world authority on such matters, Mr Jack Lyons, aka "Irish Jack".

An ace-face in 1960s Cork, Jack went on to Swinging London, and hung out with The Who and was an acknowledged inspiration for the film Quadrophenia.

When it comes to the cut of the cloth, Jack knows his stuff.

Here's a dapper dude in a sharp shirt-and-tie and a cool overcoat and tapered trousers, lurking mysteriously in a Grand Parade doorway in the early 1960s. Surely an embryonic Mod type?

"I suppose," says Jack, warily, "But if you look up close at this fella, you have to say he's really a bit of a Teddy Boy. I mean, that Crombie, that's a bum-freezer! And the hair, you know, it's a bit on the long side."

But the Mod look certainly took hold in Cork. We catch a glimpse of a young man with a pudding bowl haircut and thick specs outside the Savoy on Patrick Street, around the mid-1960s, chatting with his lady friend, who's in a Mary Quant dress and patent shoes and white tights. They look kind of shy.

"The great thing about dressing as a Mod was you couldn't get in trouble at work," says Jack. "You looked like the perfect shipping clerk, or the perfect filing clerk. You looked like management material."

Scaring up the funds for the necessary threads led to the development of a serious work ethic: "You had to have a job if you were going to buy a pair of pink sta-press trousers that would cost you an arm and a leg," says Jack. "And then they'd only be in fashion six weeks. Wear them after that and you were dead."

Not everybody back then had what it took. We see the UCC drama society of 1960, a tweedy-looking bunch, doodling by a piano in some mahogonied retreat. They've got floppy, Brideshead Revisited hairstyles and a penchant for trench-coats. We see beaming camogie teams and the McTaggart Dancers back in the 1950s. There are earnest young hobbyists from the Cork Model Aeroplane Club, looking very Just William.

But the cult of the teenager inevitably made its presence felt in Cork, and you were what you wore.

"I asked my wife about when we first met, what was it about me," says Jack, "and I was hoping to hear something about the hair maybe. Or the fact I'd been wearing a green suit that was pretty psychedelic, kind of Pink Floyd, or Soft Machine.

But she worked in a shoe shop and she said every time a guy came up and asked her to dance, she looked at the shoes . . ."

"I said, are you saying the only reason you followed me onto the floor is I was wearing the chisel-toed Cuban heel boots? She said that was it, those boots were something else. On the second date she discovered I was three inches shorter that she thought."

Loop forward again. Here's National Bike Day, 1979 and the teeming youth of Cork are huddled, Peking-style, on their Raleigh Choppers and new-fangled racers outside the County Hall "skyscraper". There are blow-dried Charlie's Angels hairdos, evocatively afloat in the summer breeze.

And now it's 1985, and a gang of kids are snapped on Grattan Hill, all sleeveless T-shirts and sweatbands and clunky old-skchool Adidas trainers and ghetto-blasters. One Anthony Crowley of Dillon's Cross is giving an exhibition of breakdancing on some flattened-out cardboard boxes.

A year later: Siamsa Cois Lao∅ at Pairc U∅ Chaoimh. Five teenage couples lie sweatily entangled on the grass in a hot rush of hormones. They are watched over by a lonesome young man, forlornly nursing a can of Harp, unlucky in love.

Onto the present day, and there are some great disposable-camera shots from senior infants at a Blarney Street school. They've snapped a world of wheelie bins and mams with frying pans and dogs and bikes and footballs and idolised siblings.

Dara McGrath, the exhibition's curator, confirms that it was quite a trawl to round all this stuff up. Many of the photos are taken from the Irish Examiner and the Kerryman archives, there are shots from private collections and from the city and county libraries. The show has been staged as part of the Cork Midsummer Festival, and it will run until July 21st. There's an open day this Friday for anyone who wants to bring in their own photographs. They'll be scanned and displayed in scrapbooks around the gallery.

Now just a few more shots. Here's a long ago sylvan summer of the 1950s and an army of kids "helping to pick two acres of peas" at Ballyhooly. And here's more white socks and BMX bikes and mullet haircuts as a pair of discontented teens mooch outside Christ The King Church at Turner's Cross in 1990. Here's Roy Keane looking amazingly polite carrying a tray of tea and biscuits at his mother's house. Here's a hula hoop demonstration outside Dunne's Stores in 1958.

And check this handsome couple sitting on their suitcases in Cobh in 1953, lighting out for a new life in America. They're a good-looking pair. She's gorgeous, a ringer for Natalie Wood; he's sharply-suited with a cocky grin.

I bet he went into real estate. I bet they cleaned up.

The exhibition Fiens and Buores has been staged as part of the Cork Midsummer Festival, and it will run until July 21st