WHAT HAPPENS when an artist who devoted most of his career to painting landscapes and still-lifes turns instead to portraiture? That’s the central premise of an exhibition of 59 portraits by Paul Cezanne at the National Gallery of Art in Washington, the first ever dedicated to this aspect of his oeuvre.

Of the 1,000 paintings the 19th-century French painter created during his lifetime, only about 160 were portraits, mostly of his close friends, family and domestic servants.

But it’s perhaps in that collection that the evolution of Cezanne’s individualistic, revolutionary vision is clearest, as he deconstructs space by boldly painting his wife with vanishing lips or applying layer upon layer of thick paint with a palette knife.

“Seated Man”, 1905-1906 /AFP

He may have studied the Old Masters, but Cezanne “exploded” traditional ways of representing space and volume on a picture plane, says Mary Morton, co-curator of the show and head of the gallery’s department of French paintings.

Cezanne in many ways paved the way to modernism.

The pioneering cubist Pablo Picasso, born 42 years after the Frenchman, called him “the father of us all”.

He relies on a “modernist understanding about how visual perception works… It’s not stable, it’s not linear, it’s not from a single point, it’s not coherent,” Morton says.

Texture was also crucial. In “Antony Valabregue” (from 1866), the artist’s submission to the official Salon art exhibition in Paris critical in launching careers, Cezanne’s rough-hewn style is on full display.

The jury took the coarsely layered paint and the poet-sitter’s defiant and inelegant pose, fists clenched on his thighs, as a slap in the face – and rejected it.

So roughly had Cezanne treated both the surface and the subject that one jury member commented he had painted not just with a knife but with a pistol.

“Gustave Geffroy”, 1895-1896 /AFP

“He is displacing the conventional place that you look for portraiture, which is the face, and that you’re expecting a likeness,” says Morton.

“It means that it’s perhaps in the colour, in the shape – it’s coming through in an unconventional way.”

Cezanne’s portraits of his wife Hortense Fiquet – who unlike her husband came from a modest background and lacked advanced education – are especially confounding.

Often unflattering, the pictures show her with an angled oval face, her hair pulled back and parted down the middle. She never |smiles.

Some are more sympathetic, such as “Madame Cezanne in a Red Armchair” (circa 1877), but that was painted before their marriage or shortly thereafter.

She is shown seated on a plush red throne of a chair contrasting with a golden green and blue wallpaper pattern.

In one work from the series “Madame Cezanne in a Red Dress” (1888-1890), she sits undisturbed in a blue room, her yellow chair and the wall tilting chaotically behind her. Co-curator John Elderfield does not, however, see Cezanne’s renderings of his wife as commentary on a possible lack of affection in a couple that largely lived apart.

“If [art dealer Ambroise] Vollard is to be believed, Cezanne did more than 100 sittings for his portrait. She has about 30 portraits, so that’s 3,000 hours. Wouldn’t you be a bit fed up sitting there?

“I think that, even though facially it seems she’s expressionless, it doesn’t mean he doesn’t care about her.” But Morton doesn’t hesitate to factor in the quality of the relationship, or at least what’s known of it.

“There’s a really tough time after they’re married. I think there’s tension and melancholy, and you get that in a lot of these. I don’t think he had an easy time with people.”

The show continues through July 1 in Washington, the last stop on a tour that took in the Musee d’Orsay in Paris and London’s National Portrait Gallery.