National Gallery brings Venetian sun to a grey London

I had one brief weekend in London between holiday travel and getting back to St. Louis to look after my mother. Top of my "to do" list was "Venice: Canaletto and his rivals" at the National Gallery, which was due to close on 16 January.

It was a top priority because I adore both this time period and this genre. I've always been fascinated by the idea of the grand tour, with those 18th century young aristocrats wandering around Italy, drinking in culture (along with alcohol and inappropriate relationships) and buying stuff to cram into their country homes back in England. One of the essential souvenirs on these tours was a scene painting of Venice, by Canaletto or a handful of competitors all working in along the canals of that magical city.

I was intrigued by the show's stated desire to compare and contrast the work of different artists. As a frequent wanderer throughout British stately homes I'm used to seeing these scenes on the walls (indeed, there's a whole dining room full at Woburn Abbey), but they're usually one offs, so you don't get the chance to see them side by side.

And the final reason: We're off to Venice for Valentine's Day, Piers' first visit to the city. A preliminary tour via oil on canvas seemed a fine idea. And so, through gray London to the Sainsbury wing, into the basement, and onto the Grand Canal.

The show delivered on expectations. What's not to like? Sunlight glimmering off canals, magnificent yet slightly crumbling architecture, crowds of people in opulent costume. Who wouldn't want one of these on his wall? My favourite room, unsurprisingly, was the large, central space dedicated to festivals and ceremonies. Vast canvasses depicted arrivals of ambassadors, flotillas of costumed teams on large gondolas or the magnificent Ascension Day ceremony during which the Doge took his golden barge, the Bucintoro, out into the Adriatic to throw a wedding ring into the sea and, by so doing, pair his republic with the seas for another year. These paintings aren't just beautiful, they are windows into another world. Worlds of opulence, colour and unimaginable glamour, each painting must have been the 18th century equivalent of today's special effects-laden film.

But what's special about this show isn't those expected scenes. It is, rather, seeing paintings of similar views by different artists grouped together. In this way you get a real sense of the strengths and weaknesses of each artist. Canaletto's confidence with light and casual disregard for reality (if an architectural feature didn't suit his composition, he just moved it). Belotto's detail. Guardi's almost impressionistic approach. Northern painters like Gaspar van Witte and Johan Richter moved south to cash in on the scene painting rage, and nobody but an expert could differentiate their work from the natives. It gives you a good sense of just how big this market was.

We both agreed that were we touring Venice in 1740, rather than next month, we probably would have returned with a Belotto. (The one at left would do.) Canaletto's nephew, he learned at the master's knee and then added his own touches, including far more respect for the architecture, thicker layers of paint and a much cooler light. He's far less known than his uncle because he worked in Venice such a short time, heading to Dresden just before his 25th birthday to carve out a career free from the older man's dominance.

What I would have loved to return from the show with, but what wasn't on offer, was a small, inexpensive paperback that reproduced the show's paintings against a map of modern Venice. Standing in this gallery comparing one interpretation of the Rialto to another was great fun. Standing in front of the same bridge comparing art to reality would be even better. Guess I'll have to load some jpegs onto the iPhone and do it myself next month.