The whole city is a gallery as art goes al fresco in York

Yesterday was a strange day for staff at York Art Gallery. For much of the morning, concerned members of the public approached the front desk informing them that a priceless-looking painting had been hung on a wall in the city centre overnight. Did they have a painting missing, they were asked? Was it being displayed in the open air on purpose or was it the work of pranksters?

In fact, when York residents awoke, there wasn't just one but 30 paintings placed on some of the city's most famous buildings. The masterpieces were not stolen, nor were they the victims of a bizarre practical joke. They had been put on show as part of an initiative by Britain's leading institutions to take art out of the gallery and on to the streets.

For the next 17 weeks, York will resemble a giant outdoor exhibition. Inspired by a similar project last year in London, which placed a series of paintings across Soho, the scheme is a collaboration between the York Art Gallery and the National Gallery.

Called the Grand Tour, both institutions have reproduced a series of life-size, weatherproof copies of some of their collections' greatest masterpieces, using hi-tech ink technology from the print company Hewlett-Packard. During the next two weeks, a total of 49 works – 45 from the National Gallery and four from York – will eventually be put on display on the streets of one of the country's best preserved cities.

One that was already attracting comment – and not a little mirth – yesterday was a lifesize replica of Quentin Massys's A Grotesque Old Woman. Its location, sandwiched between two beauty parlours in a narrow medieval passage behind York's Stonegate Street, was chosen by museum staff keen for the surroundings to echo the context of the paintings.

Created by the Flemish painter in the mid-1520s and based on a drawing by Leonardo da Vinci, the painting portrays a masculine-looking elderly woman. Art historians believe it was probably intended to be a satirical take on women of a certain age trying in vain to recapture their youth.

"All my clients have been talking about it," said Alison Cooper from Escape Nails and Beauty. "I walked past it this morning without noticing it but my daughter spotted it straight away. It's a lovely idea and has provided lots of entertainment."

Monika Badowska, a beauty therapist working next door at Beauty Bar One, was similarly surprised. "We've had crowds outside all day," she said. "It's very funny, but I hope no one thinks we'll make anyone look like that." Farther down the road Sharon Heathcote and Brian Mowbury were enjoying a bottle of red wine at a wine bar. On the wall opposite stood a 5ft tall replica of Il Bronzino's nude masterpiece, An Allegory of Venus and Cupid.

"It definitely took us by surprise this afternoon," said Ms Heathcote. "We were in this same bar last night and I'm sure there was no painting there then. We thought there might be something in the wine." Mr Mowbury added: "It's not exactly something I'd put up in my bathroom but I love the idea behind it."

The National Gallery has loaned a number of works, including George Stubbs's 1762 painting of the racehorse Whistlejacket, to the York Art Gallery for the duration of the exhibition and hopes to make it an annual event.

"Last year's exhibition in London was such a success that we wanted to take it outside the capital this year," said Clare Gough from the National Gallery. "The London exhibition was based around the gritty and cramped streets of Soho, whereas this is in a beautiful medieval city. It feels very different."