Painters Marjorie Welish and Ann Pibal both make geometric abstract work, but they are opposite in nearly all aspects of intention, approach, and affect.

Ms. Welish is a New York-based poet, critic, and painter whose current show, “Painting as Diagram,” at Björn Ressle features easel-size, sharp-edge, pristine Modernist paintings. Since the late 1970s and early ’80s, Ms. Welish has done paintings in response to historical paradigms informing Modern art, and this exhibit is a continuation of her research in art in which she considers how art might be read as well as seen.

The show brings together three recent series of paintings that demonstrate the artist’s fascination with different levels of meaning and different levels of language. The work recalls architectural plans, ideas, and schema; it includes many diptychs with information that radiates from the right and left panels, with the gap between often integrated as line or color. These are intellectualized yet playful and witty paintings, ordered with a language of line and geometry. The forms, shapes, grids, and primary colors recall Modern masters such as Mondrian, Malevich, and Rodchenko, and the conceptual conceits bring to mind American contemporaries such as Johns and Lasker.

The salon-style installation works particularly well for the newest series of works, titled “Blueprint,” which has 15 panels in combinations of triptychs, diptychs, single-panel pieces, and works on paper. Here, many aspects and elements of an idea are presented simultaneously, underscoring the chart-and-graph-like characteristic of the project’s title, “Painting as Diagram.”

One of the understated achievements is how the colors succeed in a range of duties: Sometimes they create sensory perceptions, or yield conceptual solutions, or yield pragmatic solutions. In “Indecidability of the Sign: Red, Yellow, Blue 22,” for example, a thin strip on the right edge of the painting is divided into three equal parts announcing the primaries red, yellow, and blue. In that location, the colors look like samples of themselves.

Ms. Welish paints with an economical collection of mark types and techniques ranging from scribbling and smearing to careful painting of taped-off shapes, areas, and lines. Smears are not gestures, and lines show little evidence of the artist’s hand. Like architectural drafting, which is codified, Ms. Welish’s vocabulary is far less expressive and intuitive than it is a rich, analytic, and systemic corollary of thought.

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Ms. Pibal is also a New York-based artist; her solo debut at Max Protetch offers 14 small- to human-size, surprisingly colored acrylic paintings on aluminum. The compositions are made using a range of geometric motifs, with images that recall such diverse sources as album cover illustrations and fragmented views of architectural structure. Yet it is her expressive and articulate use of color that sets this work apart.

Ms. Pibal layers one or two systems over a machine-smooth, colored ground using a grammar that implies space or atmosphere, and compositions that suggest views from different vantage points. A sense of motion and distance is achieved by skewing the fragmented rectilinear structures so they appear to be leaning, folding, or at times receding with the use of strong perspective lines. In the large painting “AERIE” and in the intimately scaled “BNKRS,” red frame-like structures are shown as if captured by the artist in mid-step as they animatedly attempt to slip offstage.

Titles are often given to paintings with corresponding images. “Pool” for example, is a large painting from 2007, with a luminous, chemical-blue ground color that is divided horizontally by a section of a striped structure. It recalls a swimming pool, albeit imaginatively and abstractly. Some titles, however, such as “FTHRWT,” “QTTRO,” and “CSHDN” — apparently ordinary words minus the vowels — are meant to underscore the notion that the work approaches this same condition of evolving language without locking into a fixed statement.

Ms. Pibal’s paintings playfully engage abstraction’s short but loaded history. Her use of striped motifs, concentric Xs, and thin lines inscribing space and outlining forms brings to mind signature moves of Americans artists such as Frank Stella, Feitelson, Krushenick, and Frederick Hammersley, yet Ms. Pibal has carved out a new space for herself. In their subtle animation of geometric form and the uncanny coupling of unnamable colors with a believable sense of light and atmosphere, these paintings feel like direct, celebratory responses to being in this world at this time.