The National Gallery of Art is to acquire about 1,700 proofs from Jasper Johns, which would make the gallery the largest institutional repository of his works.

The purchase of Johns' lithographs, etchings, relief prints and screen prints will be completed by the end of 2008. The gallery does not release exact dollar values on its purchases, but this was a multimillion-dollar acquisition, said gallery spokeswoman Deborah Ziska.

''This important body of work will permit the gallery to organize exhibitions that offer an amazing representation of Jasper's distinctive printmaking oeuvre,'' Earl A. Powell III, the gallery's director, said in a statement. The announcement was to be made official on Tuesday.

The exhibition ''States and Variations: Prints by Jasper Johns'' will open at the gallery's East Building on Sunday and will run through Oct. 28. It includes eight works from the latest acquisition, Ziska said.

The collection includes nearly all the iconic images associated with Johns from the postwar era—flags, targets, maps, large multi-panel abstractions—and recent compositions with references to works by earlier artists.

The gallery is acquiring Johns' working proofs, trial and experimental proofs, progressive and state proofs, as well as sketches made during the printmaking process.

''Printmaking is uniquely suited to tracking the evolution of an image's development through successive proofs,'' Powell said. ''Jasper's proofs take this process to new heights. While some are primary interest in the context of the final image, others are beautiful as individual works of art.''

Powell said Johns' approach has been highly influential for younger generations of artists.

''His work is essential to our understanding of the post-1960 revival of interest in print media,'' Powell said.

The gallery opened another Johns exhibition on Jan. 28—''JasperJohns: An Allegory of Painting, 1955-1965.'' It departs from the typical format of a survey or retrospective to follow four specific motifs in Johns' first decade of work—the target, the ''device,'' the stenciled naming of colors and the imprint of the body.

The exhibition shows how Johns created art about the process of making a painting, said Jeffrey Weiss, the gallery's chief curator of modern and contemporary art. The show runs through April 29.

Besides Johns, the gallery has acquired the most extensive institutional holdings of works by several other 20th-century artists, including Richard Diebenkorn, Robert Frank, John Marin, Mark Rothko and Alfred Stieglitz.

By Brett Zongker, copyright 2007 Associated Press