Sunset on the Sand Dunes of Jean-de-Paris

By Theodore Rousseau.

At Wadsworth Atheneum,

Hartford, 860-278-2670, www.thewadsworth.org

HARTFORD — This late landscape by Theodore Rousseau, one of the 19th century’s greatest yet most undersung artists, may look rather ordinary in reproduction. Believe me, it’s not.

Go see it in Hartford, where it hangs in the Wadsworth Atheneum. I suspect you will never forget it. To me, it is one of the most mysterious and arresting landscapes ever painted.

It is a view of the sun setting behind sandy hills in the Forest of Fontaine­bleau, an area to the southeast of Paris that Rousseau and his fellow Barbizon School painters helped to make famous. Casual inspection is enough to reveal sketchy outlines and, in places, a ghostly image showing through from beneath, suggesting both that it was painted over an earlier, abandoned image and that it may have been partially unfinished itself.

What fails to come through in reproduction is the painting’s bizarrely glowing color. Stand in front of it, and your eyes will need time to adjust. Rousseau’s pervasive, high-wattage shades of orange and pink interact with (and for the most part overwhelm) a variety of dull greens. Patches that shift toward turquoise punctuate parts of the foreground.

Taking the whole image in, it’s as if both the vegetation and the surrounding atmosphere have become gauzy filters, stretched to bursting by the strain of mysterious forces pushing through from below and behind. The wispy green grass and shrubs are no match for the swelling earth, while the thin clouds are no match for the force of a sun in its death throes.

Rousseau was a realist. Provoked by the example of John Constable, and by the reticence, the absence of rhetoric, in the landscapes of Camille Corot (who also painted at Fontainebleau), he wanted to paint landscape for its own sake. And he was superb at it.

Rousseau’s almost Chekhovian aversion to rhetoric and symbolism had cost him dearly for much of his career. He was rejected by the Official Salon, denied honors and esteem for longer than almost any major artist of his time.

He did not betray the simplicity of his vision here. There are no hovering angels, no “black monks’’ (I’m thinking of Chekhov’s great story), no divine shafts of light poking through clouds to illuminate the strangely selective workings of divine grace. . .

And yet the painting, which Rousseau worked on over the final three years of his life (he died in 1867, at the age of 55), is charged with a power that can’t be described without resorting to the language of spirituality.

It’s either that, or a case of acknowledging that language has no hope at all.

Sunset on the Sand Dunes of Jean-de-Paris

By Theodore Rousseau. At Wadsworth Atheneum, Hartford, 860-278-2670, www.thewadsworth.org

Sebastian Smee can be reached at ssmee@globe.com.