“Sea and Shore,’’ for instance, shows a big black rock at the center of a swathe of shadow-encrusted green meadow below and blue-violet sea above, with only a very thin strip of sky along the top.

There’s something clean and unfussy, but never prim (which Hopper could occasionally be later in life) about the results. One becomes aware, moving around the show, of looking at confidently troweled-on blocks of saturated color harmonizing in the most satisfying ways.

Many of them are quite tightly cropped, almost as if Hopper were looking through the viewfinder of a camera. He might, for instance, include a horizon line right near the top of the picture, or leave it out altogether, preferring to zoom in on idiosyncrasies of rock or sea.

There are only about 30 of these Monhegan pictures. They are all pretty much the same size and they’re not dated. All we know is that they were completed between 1916 and 1919.

Quite often, Hopper used a palette knife to create cakey textures or zigzagging striations that evoke geological layering. Elsewhere, he worked with a loaded brush, leaving behind a thick impasto to suggest surf sluicing around rocks or crashing into cliffs.

They are small plein air studies that belong to a tradition kicked off by French painters working outside in Italy in the late 18th century. All about paint and light, they’re fresh, fresh, fresh. The compositions are idiosyncratic, there’s no under-drawing, the colors are rich, the shadows sharp, the bristles of the brush visible in each juicy brush stroke.

If he painted waves - as in the Currier Museum of Art’s “The Bootleggers,’’ or the Worcester Art Museum’s “Yawl Riding a Swell’’ - they were never going to crash, throwing up drenching spume and spray. Rather, they were like the stiff undulations of an upset rug in a house ransacked by robbers.

Hopper is better known, of course, as America’s great painter of uneasily empty interiors, solitude in the city, and uncanny rural quietude. We know, from his many depictions of New England lighthouses and coastal architecture, that he liked to summer by the sea. But his mature style was dominated by an insistence on sturdy (if, at times, unnervingly tilting) geometry and a proclivity for thinly applied paint.

It is, along with “Pissarro’s People’’ at the Sterling and Francine Clark Art Institute, the show of the New England summer.

But this is the Hopper we’re introduced to in the first two rooms of a terrific exhibition at the Bowdoin College Museum of Art in Brunswick called “Edward Hopper’s Maine.’’

His first two summers in Maine were spent painting in Ogunquit. If you wander through the intimate, coast-clinging grounds of the Ogunquit Museum of American Art, you can get a strong sense of what Hopper saw, for it was from this precise location that Hopper painted most of his first Maine pictures.

Hopper first came to Maine in the summer of 1914. He had settled in New York, after making three trips to Paris between 1906 and 1910. His painting was progressing slowly in part because of the demands of his job as a newspaper illustrator. He completed only about 15 oils in four years, according to Carol Troyen, a Hopper expert at the Museum of Fine Arts, in an essay addressing Hopper’s early years in Maine

The latter, a large and hauntingly spare painting of an inshore motor fishing boat grounded on grassy sand dunes, has long been thought unfinished (it is unsigned and was unregistered in the artist’s record books). But in a separate catalog essay Carter E. Foster argues persuasively that Hopper considered it finished.

Still, it is a treat to see so many of Hopper’s watercolors, not to mention a smattering of drawings, etchings, and several powerful oils. Most notable among these are “Captain Upton’s House,’’ a painting in the collection of comedian Steve Martin (who has contributed an attractive essay to the catalog), and “Maine in Fog.’’

After seeing these early Monhegan views, it takes some time to adjust to the prevailing tenor of the rest of the show, which can seem at first a little dry and dour.

Given his influence, the surprise is not, perhaps, that Hopper started out painting this way, with a loaded brush and wristy insouciance. It is that he gradually shifted away from this manner toward a style that was much more sober and deliberate.

Hopper was one of several notable students of Robert Henri, who conducted life-drawing classes at the New York School of Art at the beginning of the 20th century. Henri implored his students - among them George Bellows, Rockwell Kent, and John Sloan - to “Paint what you feel. Paint what you see. Paint what is real to you.’’

That is part of what makes this exhibition so worthwhile. It’s the first ever to focus on Hopper’s time in Maine, a state he visited over nine summers between 1914 and 1929. (From then on, he favored Cape Cod).

These Monhegan pictures are seldom seen (most of them belong to the Whitney Museum of American Art), and they are hard to square with one’s prevailing idea of Hopper.

What ignites the picture are the two small patches of bright white surf visible through gaps in the rock. The effect is austere and magisterial, reminiscent of the landscapes of Hopper’s British contemporary, William Nicholson.

The Ogunquit paintings constitute Hopper’s “first sustained artistic engagement with nature,’’ writes Troyen. In them, we see him struggling to find an idiom that suited both his temperament and the complex, ever-shifting interplay between rocks and sea. He alternates between a very free style (“Dories in a Cove’’) and a drier, more deliberate idiom which feels a little flat.

Only when he turns away from the sea do you feel him arriving at something convincing and fresh. “Road in Maine,’’ a modest view of a curving dirt road with three telegraph poles set among some rocky hills, is both the biggest and the best of these earliest paintings. The way the artist captures the green-streaked atmosphere streaming from the hills into the sky chimes with everything one loves about the later Hopper: his delicacy, his interest in observed, specific truths over dramatic flourishes; his well-tempered feeling for color and light.

In 1916, encouraged, perhaps, by Henri, Bellows, and Kent, Hopper chose Monhegan instead of Ogunquit, and really came into his own. None of these 30-odd pictures was worked up into a larger composition; none of them was included in subsequent retrospectives, and most of them remained unsold in his studio until after his death. I envy whoever first came upon them. What a discovery!

Hopper, however, was not satisfied. He must have felt these Monhegan pictures were too close to those of his mentor, Henri, and to Bellows and Sloan. (The museum has selected, by the way, a number of pictures of Maine’s coastline by Hopper’s contemporaries, including Henri, Bellows, Sloan, Kent, Marsden Hartley, John Marin, and Andrew Wyeth, for a separate, concurrent exhibition.)

Given everything Hopper went on to achieve, who are we to second-guess him? The exuberance in the Monhegan pictures, while less pronounced than in those of his peers, did not, finally, match his temperament.

“It takes a long time for an idea to strike,’’ as he admitted. “Then I have to think about it for a long time. I don’t start painting until I have it all worked out in my mind.’’

The rest of the show, with its preponderance of watercolors, drawings, and prints, draws us into this slow and deliberate working method.

The etchings, which Hopper began working on about the same time he started going to Maine, come first, and they are marvelous. The nature of the medium - scratching marks into a copper plate - encourages fastidiousness. But Hopper’s mark-making is impressively free, and the imagery, as in “The Lighthouse,’’ a work that would be revisited in many of Hopper’s most famous oils, is bewitching.

Every now and then, Hopper expresses the wry humor that we know was part of his ostensibly sober character: See, for instance, “American Landscape,’’ which shows the north ends of two southbound cows.

After some trips to Gloucester, and his marriage to fellow painter Jo Nivison, Hopper returned to Maine in 1926. This time he went to Rockland. The following year, and in 1929, he spent time in Portland, Pemaquid, and Cape Elizabeth.

He gradually gave up etching and focused on watercolors. The commercial success he henceforth enjoyed did not prevent him from seeking out subject matter that was less than picturesque. He depicted lime rock quarries and the decks of boats, always with an eye for the oddly cropped view or the unexpected vantage point.

Eventually, he focused more of his attentions on lighthouses, producing some of his most enduring and memorable images in both watercolor and oil. Only one of these pictures, the radiant “Pemaquid Light,’’ has any figures in it. So if one hungers for Hopper’s inimitable way with narrative, his ability to place singular figures in settings at once serene and charged with psychological potential, one is going to come away a little disappointed.

But the show as a whole expresses a lovely, limpid vision wholeheartedly in debt to Maine. It would be madness to miss it.

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

© Copyright 2011 Globe Newspaper Company.