The exhibition on the Impressionists at the Vittoriano in Rome is like a gift; entering rooms hung with pictures full of light and air, and sparkling with joyful and well-considered brushwork, you breathe more lightly.

In the beginning, western painting was poster art. Duccio, Giotto, Piero della Francesca, the Sienese were advertising the dogmas of the Church and the virtues of Christ and the saints in sheets of bright, clear colour contained by tight, strict outline. With the Renaissance came a looser approach and views into luminous distances. These distances were more turbulent and more distinctly divided into light and shade in the Baroque. Then, after Neo-Classicism, came the return to tightness which we can see in the exhibition Maest di Roma now in Rome (see Whats on, page 12), which fiercely celebrates the heavy hand of the Academy, and which makes you understand why Impressionism absolutely had to happen. You can also understand why those fragrant lovely impressionist pictures in their own time were seen as tough, wild statements by determined, rabble-rousing rebels.

By the late 19th century the sculpted outline, the smoothness of finish, the carefully weighed composition, the dark, dated story, were suddenly seen as cumbersome. The surface of the painting itself, the vibrant dabs of pure colour that was the story.

The impressionist radicals loved the outdoors above all else. The wide, sunny, windy land of France stimulated women and men to work out vast, bright fabrics these were landscape painters par excellence. But they certainly embraced their own daily life as well: the way a pear settled on a plate; the way a lady in a velvet frock turned her head; the way friends and children looked out at the painters; the way everyone casually stretched and stood and walked and rode; how they sat in the comfortable clutter of studios and salons.

In this exhibition, landscape has been set aside in favour of those intimacies, so we can concentrate on domestic drama and daily habits. Sitters in a natural pose, in silhouette, flowers nodding, a painter reading a newspaper, another with brush poised to touch canvas, a woman with a bad leg stuck out under her huge skirt all of them busy in their own time, as if in a photograph. Indeed the new invention of photography played quite a part in the impressionist pursuit in its fascination with movement, arbitrary and brusque cuts of figures, the instantaneous snapshot quality of pose.

So it is no accident that photographs of the protagonists are welcome starters to this show. Here are the painters, clumsy or genial, thoughtful and humble, Monet with a beard and dented hat, Pissarro with big boots, Berthe Morisot in a satin gown, artists children with gleaming, freshly brushed hair, sturdy women painters and sturdy wives they are all a complement to the painting that follows.

The works on show have been lent by museums from all over the world, and some from remote ones, so they have been seen rarely. In one of the first rooms an array of deliciously small works oils, pastels, etchings nearly breaks your heart.

In addition to the French artists there are three Italians: Giuseppe De Nittis, the least well-known, Giovanni Boldini and Federico Zandomeneghi. They were first close to the Tuscan macchiaioli. Then, after settling in Paris, they became close to the Impressionists. De Nittis is a discovery. One of his small paintings, full of happy observation, intriguing casual detail and visual wit, shows a woman rider in conversation with walking friends in the Bois de Boulogne.

There is Monets painting of his Camille in a green gown, his father in prima maniera, and his painting of women rowing on the Epte, where he, as he himself wrote, attempted the impossible: to render the lacquered dark depths of the swift flowing river in luminous paint.

By Manet there is a painting of Jeanne Duval, Baudelaires companion, ill but majestic, and his Morisot, goyaesque in delectable velvet. There are Degass oils of young French corporate raiders, a mischievous painter in his studio, traders in the New Orleans cotton exchange.

It is in the late 1800s that women came to the fore, four of them among 15 men here, with Morisot one of the best. By Morisot herself there is not only a charming portrait of Madame Boursier and her daughter with flashing background, but a study of a woman doing embroidery. Practically quivering with brushmarks, rapid, exuberant, dazzlingly unfinished, it is one of the most willfully open examples of pure Impressionism.

The American John Singer Sargent and Boldini both fashionable and often too flashy portrait painters here are at their most thoughtful and inventive.

Why is it that impressionist painting, of a time so far from our own, is still so satisfying? All these alluring works are records of a busy and safe period, infinitely less brutal than our own. But the marvellous thing is they are more than records. They are flashes of moments of deep pleasure, when artists saw and enjoyed the sensual, living world around them and, rendering it with careless skill, gave it to us transfigured.

Ritratti e figure. Capolavori impressionisti. Until 6 July.

Complesso del Vittoriano, Via di S. Pietro in Carcere, tel. 066780664. Mon-Thurs 09.30-19.30. Fri-Sat 09.30-23.30. Sun 09.30-20.30.