Ideas about what’s beautiful can change in unpredictable ways.

Consider the art of Beatrice Cuming, a painter who spent much of her career in New London. She chronicled her era in vibrant scenes that show infrastructure, waterfronts and people, many of them set in familiar locations.

The full scope of her work is on display at the Lyman Allyn Art Museum in “Beatrice Cuming: Connecticut Precisionist,” a lively look at her 20th-century world, here and elsewhere.

The strongest theme is her documentation of industry: as a New Deal artist, in corporate commissions and on her own. Like other members of the Precisionist movement, she was inspired by technological progress and once declared that “mechanized America is beautiful.”

Cuming’s paintings of bridges, shipyards and power plants are a colorful evocation of geometric shapes, functional architecture and possibility, and she found beauty even in the light from a welder’s torch.

But there’s one subject, of which she seemed especially fond, that stands out as a curious anachronism. In painting after painting, Cuming portrays smokestacks pouring dark clouds of exhaust into the sky.

Those high chimneys may evoke the industrial era better than anything else, but the symbolism hasn’t aged well. If to earlier generations they stood for progress, today they seem to say only “pollution.”

In an oil on canvas titled “Towering/Smoke Stacks,” Cuming portrays a quintet of chimneys expelling dingy brown smoke at what’s believed to be a power plant in New Bedford, Mass. An etching of the same scene, drained of that unpleasant color, works better for modern eyes.

For an older perspective, here’s a 1937 quote from The Day about a similar Cuming painting being displayed by the Mystic Art Association: “Her Gas Tanks with accents of black smoke and white steam are towers of beauty.”

Cuming (1903-1974) worked in different media, but oils predominated, invigorating with bright hues scenes we sometimes associate with black-and-white photos.

In a Groton view from 1941, a construction derrick bisects the canvas diagonally while hard-hatted workers raise their arms, one to direct its movements, others to grab a descending hook. The composition is fascinating, and the derrick is a striking shade of red.

Scenes like this came from Cuming’s job with the Works Progress Administration, a New Deal agency that employed artists to document life during the Depression. Cuming submitted paintings for placement in schools and municipal buildings. She also took part in efforts like a mural project at the Coast Guard Academy.

One of her assignments was to show harbor defenses in Long Island Sound, which led to a portrait of a 10-inch gun at Fort Wright on Fishers Island. The massive weapon, with gears that raised and lowered its carriage, fit perfectly with her interest in technology.

The local waterfront was rich with topics, and another that attracted her eye was the awkward bulk of bell buoys in storage on a Coast Guard dock behind the Custom House in New London. Heeled over on big cylindrical bases, they look like fish out of water, which they sort of are.

A painting of a shipyard is without any ships, focusing instead on machinery used to make them. An overhead cargo crane and a railroad flatcar move sheet metal along the building ways before it becomes part of a hull.

Cuming’s affinity for scenes like this made her a natural to depict the workings of industry, and two companies hired her to chronicle their operations. One was Standard Oil, which patronized the arts and featured new works in its own publication. A painting she did in 1946 shows a Pennsylvania plant where barrels are stacked around a cluster of gas tanks crisscrossed by metal staircases.

An ordinary person might look past a scene like this without a thought. In 1937, while explaining to The Day why she decided to paint a locomotive, Cuming said artists do the same thing.

“It is quite possible to walk by an object for two years or more without knowing it exists,” she said. “Most of us are doing it year after year. Then suddenly, in the right mood, we are attracted to it in a way we have never realized before. We see an exciting picture in it.”

Cuming’s other industrial commission produced exciting pictures closer to home. She was working as a security guard at Electric Boat in 1943 when the company put her talents to better use. In the thick of wartime submarine production, the place offered plenty of material.

In “Chubb,” the view is through a hull section of a sub in the early stages of construction. Much of the canvas is filled with scaffolding and ladders, creating a busy backdrop of triangles and rectangles. Three workers are almost lost in the confusion.

While this is recognizably a shipyard, a closer perspective, in “Welders at Electric Boat Company,” could pass for science fiction. Heavily masked faces bend over their work as a ring of bright smoke rises around them and large unidentifiable shapes loom in the background.

These two paintings capture one of southeastern Connecticut’s great moments of industrial might, and it’s unfortunate that at least five others Cuming did for EB have not been located.

The exhibition opens with a survey of Cuming’s early work, which reflects a young artist in search of her own visual language. The media include watercolors and charcoal on paper, the technique is sometimes impressionistic, and the varied subject matter came from her travels in Maine, France and North Africa.

There are downtown streets in Boothbay Harbor, circus performers in Paris, and village markets in Tunisia. The scenes are lovely, though not especially predictive of what her style and interest would settle into.

Cuming, who moved to New London almost by chance in 1934, later called the city “inexhaustible for subject matter, and in every way agreeable and good for work.” She was drawn to the waterfront and painted calm scenes that show rippling water and the curves of vessels.

One of the most interesting is “The Architecture of Light,” in which City Pier is viewed from above. The pattern of concrete squares is broken dramatically by long diagonal shadows from a solitary figure and higher elements of the pier.

New London scenes like this, and others of buildings and staircases, have an obvious kinship to Cuming’s industrial studies. But a handful are strikingly different and among her best work.

In much of her output, Cuming subordinates human figures to structures or leaves them out entirely, but two crowded street scenes are about people who brought downtown to life.

“Saturday Night: New London” is recognizable as lower State Street by the train station and Soldiers and Sailors Monument. But it’s a place we no longer know, where Navy men flirt with young women and people are everywhere amid brightly lit signs and movie marquees.

An untitled companion piece, set around the corner on Bank Street, is even more alive. A close view from the sidewalk shows a mixed-race crowd bathed in the glow from a drugstore, whose open door reveals customers at a soda fountain. Against a backdrop of shop-window advertising, the dominant figure is a strutting woman in a translucent yellow dress. People in this scene could be New Londoners of today, but they inhabit a lost world.

The two sides of Cuming’s art keep alive a local moment in time. One shows the region’s work and places, the other its people. We can be grateful for the former and wish there were more of the latter.

j.ruddy@theday.com

If you go

What: “Beatrice Cuming: Connecticut Precisionist”

Where: Lyman Allyn Art Museum, 625 Williams St., New London

When: Through May 26

Hours: 10 a.m.-5 p.m. Tuesday-Saturday, 1-5 p.m. Sunday

Admission: Adults $12, seniors $9, active military $7, students $5.

Information: lymanallyn.org