“The Human Flood” is a collaborative project, guided by curator Laura Roulet. It includes drawings, videos and sculptures that make canny use of the site. Outside, Arkin’s tidy tents and Weiss’s patchwork domes represent the sort of temporary migrant housing that all too often becomes permanent. Equally laden with symbolism is a skeletal house Arkin erected inside the building; its partial walls are made of recycled clear food bins packed with shredded financial documents, which the gallery guide calls “remnants of power.”

Also within the gallery are the artists’ life-size drawings of climate refugees. They’re printed on clear vinyl and applied to the windows, so that the people appear to be staring into a refuge that’s just out of reach — essentially floating between two worlds. Stacked nearby are sandbags, ready to be deployed against rising tides, yet surely inadequate to the task. A pile of sand is strewn with shoes and plastic jugs, and a three-screen slide show flashes images of water, trash, exiles, shantytowns and cataclysmic weather.

More drawings of émigrés on the move through hostile climes are affixed to the walls or printed on gauzy hanging banners that partly block movement through the gallery. The throngs of anonymous figures may appear overwhelming, yet they’re not meant to be seen as a threat. “The human flood is not something of which we’re afraid,” notes Arkin in an interview included in the show’s catalogue. Environmental degradation may be the occasion for Weiss and Arkin’s project, but the impetus is an affirmation of universal humanity.

The exemplary item in “Dickson Carroll Retrospective, 1973 to 2023” is a model of a proposed canopy for the Cleveland Park Metro station, the closest stop to the artist’s home. Made of brightly painted wood, the proposed structure is both whimsical and functional. The canopy is the antithesis of the machine-tooled blankness that dominates contemporary architecture. Yet Carroll is a practicing architect as well as a maker of charmingly cartoonish furniture and purely abstract sculptures that — like all the artist’s products — are beautifully made and elegantly finished.

Curated by Christopher Addison, who exhibits Carroll’s work at his Addison/Ripley gallery, this survey of candy-colored woodwork is set off by black-painted walls. The dark environment accentuates the artist’s bold hues and the various ways he enlists illumination. “Lighthouse” glows from a bulb nestled within, and among the semi-practical pieces are many mirrors within extravagantly meandering frames. Gazing at their reflections, even the most self-regarding viewers will probably smile at being upstaged by the swoops of red- and green-coated wood that enclose the glass.

Vivid color is also key to the most striking pieces in “Travelin’ Light,” a selection of assemblages by Renee Butler. She places images in clear plastic bags and arranges them in grids. Many of the pictures are photos Butler made of animals while on safari in Kenya, but several sets depict consumer goods in profusion. While the photos are usually presented straightforwardly, one group of safari snapshots has been gashed so that the gray wall behind them is visible through the slits.

This treatment of photos is akin to the approach of the show’s three abstract collages, made of pieces cut from translucent theater gels. Also placed in plastic bags, these disconnected blocks of green, pink and other hues are energized by sunlight from nearby windows. Butler studied with Washington colorists Anne Truitt and Sam Gilliam, and she has devised a distinctive variation on the tradition they represent. Rather than adapt color painting to 3D formats, as Truitt and Gilliam did, Butler frees pure color to float in seeming emptiness.

The earliest dated pictures in Jack Boul’s “Perceptual Painting” are two 1964 views of rooftops in New York City, the 97-year-old’s hometown. By the time he depicted those modest buildings, Boul was well established in Washington, where he has lived since 1951. The artist, who taught at American University for 15 years, has always been a traditional realist with a mastery of classical techniques. But his work did become looser in D.C., as is illustrated by two sketchy 1972 studies of the C&O Canal made with oils so diluted they resemble watercolors. The pictures are among the most appealing in this small survey, which features renderings of such characteristic subjects as cows, rustic landscapes, and the interiors of European cafes and theaters.

One way that Boul softened his style was by making monotypes, one-of-a-kind prints produced by drawing on a nonabsorbent matrix and then transferring the image to a sheet of paper. Pictures made by this method are the focus of “A Brush With Printmaking: Monotypes by Jack Boul,” a show at the Art Gallery at Stanford in Washington. These painterly prints were executed in brownish black-and-white that’s ideal for their often shadowy locations, which are sometimes punctuated by luminous accents.

Boul is drawn to solitary people, whether they’re eating, thinking or sitting on a bench with strangers. Trees and storefronts on empty streets also appear lonely in the artist’s prints. Yet other pictures capture shared moments, of audiences in a theater or a dancing couple. The latter is a smeary silhouette that splendidly conveys both motion and a profound, if perhaps fleeting, sense of communion.

Ellyn Weiss and Sondra N. Arkin: The Human Flood

Dickson Carroll Retrospective, 1973 to 2023

Renee Butler: Travelin’ Light

Jack Boul: Perceptual Painting

All through Aug. 11 at the American University Museum, Katzen Arts Center, 4400 Massachusetts Ave. NW. american.edu/cas/museum. 202-885-1000.

A Brush With Printmaking: Monotypes by Jack Boul Through Aug. 11 at the Art Gallery at Stanford in Washington, 2655 Connecticut Ave. NW. siw.stanford.edu/art-gallery. 202-803-8100.