The Adamson Gallery exhibit “Gordon Parks: An American Lens” is nominally a retrospective, and it does a solid job of hitting the high points of the famed photographer’s long career with the Farm Security Administration and then Life magazine—-his iconic variation on “American Gothic,” a portrait of D.C. custodian Ella Watson with a broom and mop in front of an oversized flag; an image from Parks’ visceral series on teenaged Harlem gang leader Red Jackson; black-and-white portraits of such leading African American figures as Duke Ellington, Ralph Ellison, Muhammad Ali and Malcolm X; and even a smattering of frothy high-society fare.

A series in which Parks documented his native Fort Scott, Kan., channels his bittersweet memories of the place and the difficult childhood he faced; the images’ tonalities are muted, but there are also glimmers of cheer in the photograph of nude swimmers in a watering hole and figures disappearing into a forest clearing, which evoke Thomas Eakins and W. Eugene Smith, respectively.

But the emotional core of the exhibit is Parks’ 1956 series on segregation in Mobile, Ala., part of which was published in Life but much of which languished in archival obscurity for more than half a century. Parks’ images of the era’s routine discrimination and deprivation are no-nonsense—-a marquee advertising “colored lots” for sale; an unpainted shack served by a rickety water spout (middle); a black girl looking through the window of a clothing store that has only lily-white mannequins—-and in some cases seem a tad contrived, as when a group of children looks through a chain-link fence at a whites-only fair.

But this serves to lay bare the ridiculousness of Jim Crow, such as the identical water fountains with “white” and “colored” labels slapped on with utter arbitrariness, and the windows of the soft-serve joint where the same employee serves both races, in windows just inches apart (bottom). Occasionally, art and morality meld with aplomb, as in “Department Store, Mobile, Alabama, 1956” (top). In one decisive moment, Parks captured a maraschino-cherry-red “Colored Entrance” neon sign; the expressive faces of a mother and a girl; and a series of bold diagonals.

Through May 31 at Adamson Gallery, 1515 14th St NW, Washington, D.C. (202) 232-0707. Tue-Fri, 11:30-5:00 and Sat 12:00-5:00