Pioneering Washington printmaker Lou Stovall knows as well as anyone that screen-printing is often used for such purely functional endeavors as poster and sign-making. He first encountered the process as a teenager in 1950s Springfield, Mass., where he took a job at a grocery whose signs were produced in its basement silk-screen shop. From this introduction to the technique at its most pragmatic, Stovall developed into an exceptionally bold and innovative screen-printer. That legacy is surveyed in “On Inventions and Color,” a multipart show at the Kreeger Museum.

Stovall came to Washington to attend Howard University in 1962, and has been here ever since. He’s made elegant prints, both abstract and representational, from his own designs. He also printed the work of many other artists at his atelier, Workshop, Inc., established in 1968 and operated until 2020, when, during a storm, it was destroyed by a falling tree. Along the way, he even made a few posters and signs — for "be-ins,” jazz performances and art exhibitions, not apples or ground beef. Some of them were exhibited last summer at Hemphill Artworks in a show titled “What’s Going Around: Lou Stovall & the Community Poster.”

Curated by Danielle O’Steen, “On Inventions and Color” fills the three galleries on the Kreeger’s ground floor. One holds Stovall abstractions, including four gorgeous monoprints (one-of-a-kind images crafted with printmaking techniques) from 2009 to 2010. Another includes prints by other artists, made (often with Stovall’s essential assistance) at Workshop, Inc. The space that links these two rooms contains delicate, precise nature-themed Stovall prints, as well as a few related pencil drawings, most of them from the 1970s.

Supplementing the show is an exhibition, upstairs in a small gallery, of six gentle nature prints from “Of the Land,” a 1974 Stovall project just published as a book of prints and verse. These are joined by a handwritten version of one of the poems the artist wrote to accompany the artwork.

Screen-prints are made by attaching a stencil to a thin mesh; ink is applied evenly with a squeegee and seeps through to the paper wherever the stencil doesn’t block it. This process yields a hard-edge image that’s ideal for such text-heavy pieces as signs. Screen-printing also, on a much more sophisticated level, suits such crisp works as Paul Reed’s 1969 “Barcelona,” which simulates a 3D structure in Day-Glo hues; and two Gene Davis prints from the 1980s that rhythmically array stripes in black, gray and multiple shades of green, blue and purple.

These are among the pictures by D.C. artists included here as examples of Stovall’s immaculate printing technique. Also showcased are Workshop, Inc.-realized prints by such notable Black artists as Lois Mailou Jones (who taught Stovall at Howard), Jacob Lawrence and Louis Delsarte.

The Lawrence screen-prints, from a series on the life of Haitian revolutionary Toussaint L’Ouverture, are hard-edged. But the Jones and Delsarte prints have a seemingly painterly softness that’s shared with lovely works by Di Bagley Stovall, Stovall’s wife, and Sam Gilliam, a frequent collaborator. Particularly remarkable is Gilliam’s “For Xavier,” a circle-centered abstraction whose bold colors appear raked, as if someone had dragged a multi-tined implement through thick wet pigment.

In an interview with former studio assistant Anne C. Smith in the show’s excellent catalogue, Stovall discusses his innovations. He applies a lacquer thinner to the stencil to partially dissolve it, thus yielding a stippled image. He uses oil-painting brushes, dipped in the thinner, for similar effects, and prints multiple layers of translucent ink atop each other. (The results can be as complex as the multiple glazes employed by classical oil painters.) And, yes, he did devise wooden tools to inscribe patterns into ink.

As Stovall says in the interview, “No rules.”

That audacity has paid off many times, notably in the four 2009-2010 monoprints that are this show’s most recent works. They’re as much paintings as prints, since they were made without stencils. Stovall applied the inks through a screen, dripping, splashing and spraying as well as squeegeeing. Each picture is free-form yet impeccably controlled, whether the heathered, allover “Winter Roses” or the smoldering “Vespers,” dominated by half of a sun-like yellow-and-orange circle.

Perhaps the artist wasn’t thinking of the sun when he made “Vespers,” but nature imagery is common in his art, whether realistically depicted or barely hinted at. Birds and flowers abound in Stovall’s prints, even when reduced to their essence: the colors, shapes and sense of movement that animate even his most improvisational work.

If you go

Lou Stovall: On Inventions and Color

Kreeger Museum, 2401 Foxhall Rd. NW. 202-337-3050.

Dates: Through April 16.

Admission: $10 suggested donation; $8 for students, seniors and military personnel. Timed-entry passes required.