James Welling has been exploring the gap between photographic referent and image for nearly 40 years in his experiments with the continually evolving technologies and materials of the medium. Working in series distinguished as much by process as by subject, he injects postmodernist critique with a poetic sensibility. As he remarked in a 2011 interview with Steel Stillman in these pages, "Like Wallace Stevens, I want my work to resist the intelligence as long as possible." In his latest New York show, "Overflow," three distinct bodies of work refract the artist's ongoing investigation of photography through a deeply sensual beauty.

The photograms from the 68-page book Frolic Architecture (2010), several of which were on view at Zwirner, were created by painting and folding a sheet of clear Mylar and then contact-printing it on photographic paper. The works have a fluid quality expressed in the silvery gray of black-and-white photography, representing nothing other than the material process of their making. A collaboration with the poet Susan Howe, the book combines Howe's collage poems inspired by writings of the 18th-century American theologian Jonathan Edwards (whose concept of "presence" is central to Michael Fried's writings on modernism) with Welling's meditation on transparency and light.

To make the images in the series "Fluid Dynamics" (2012), Welling exposed wet photographic paper to light, processed and scanned the results, and then digitally manipulated the hues. The images resemble waves and splashes of colored liquid: acid blues and pinks in the 5-by-4-foot G19V1 and oxidized greens and purples in the nearly as large FD1M. The quasi-scientific character of these titles seems like a link to photography's history as a mode of experiment even while the images disrupt the indexical ties to the material world so valued by its early practitioners.

The high-key colors in "Fluid Dynamics" are not wholly arbitrary, however. They are derived (with the help of Photoshop) from hues in the "Wyeth" works, also on view. Since 2010, the Los Angeles-based, Connecticut-born Welling has been photographing in Maine and Pennsylvania in order to trace the vision and life of the American painter Andrew Wyeth (1917-2009), who was one of his earliest artistic influences. The images in "Wyeth" are brimming with content. Some, like End of Olsons (2010) and Groundhog Day (2010), re-present familiar scenes from Wyeth paintings; others, such as Easel (2010) and Dry Pigments (2011), depict the artist through his tools.

With a palette dominated by natural greens and browns, the mood of these pictures is melancholic, as in Wyeth's paintings of solitary figures in spare New England houses and landscapes.

Though Wyeth pictured the world around him, he did not paint from nature but constructed his compositions from sketches. Similarly, Welling's pictures of Wyeth's world emerge from digital composites of multiple shots, a process that does not simply make photography more like painting but asks whether it can ever be simply a documentary medium. The "Wyeth" series tells two stories at once. The first is about the painter, evoked through the spaces he inhabited and painted; the second is about the construction of images. By delivering these stories together, Welling makes a compelling case for their intimate connection as well as their radical difference.

Photo: James Welling: Dry Pigments, 2011, inkjet print on rag paper, 16 by 24 inches; at David Zwirner.