For many, the opening Thursday night of the National Gallery's "Master Prints From Private Collections" exhibition was yet another example of Washington's emergence as a locus for fine art collecting. Twenty years ago, reminded a gallery staffer, this exhibition could not have taken place. To be sure, in 1964 -- a year with nary a Hirshhorn nor East Building on the horizon -- there was much that did not take place. It was a year, however, in which a group called the Washington Print Club began. The National Gallery's exhibition of private collectors' treasures honors the club's 20th anniversary and the state of capital city collecting.

Among those walking through the three small, well-lighted rooms containing the exhibition were some who had acquired their prints relatively recently, and for reasonable sums. Sherwood B. Smith Jr. admired "The Woman on the Hinny" by Dutch painter Jan Both, a print he acquired seven years ago. "It becomes addictive to buy . . . and buy cheap," Smith said, recounting how he bought this particular Both, one of a series of six.

Many were the serendipitous tales of buying rare prints only to discover that they were even rarer than previously thought. One woman, whose husband owns a print of Matisse's "Nude," told of his experiences as a novice collector in New York City. "A dealer said to him, 'If you can afford a painting, buy an original.' " That print truly "shows the mastery of the line," she commented on the Matisse, sighing wistfully.

The exhibition, in the West Building through March 3, encompasses an impressive range of European and American artists, including a host of early- and mid-20th-century Americans -- Benton, Hopper, Sloan, Rauschenberg and others -- each more beguiling than the last.