With admirable timing, the Smithsonian Institution premiered its refurbished and updated American Art Museum and National Portrait Gallery in Washington, D.C., on this long Independence Day weekend. After six years and a cost of almost $300 million, the two museums can once again be visited in their joint home, the old U.S. Patent Building, a 19th-century Neoclassic landmark a few blocks north of the National Mall, now lovingly repaired, updated, expanded and reconfigured.

Partly paid for by the government and partly by private donations, the two museums now bear an additional appellation -- the Donald W. Reynolds Center for American Art and Portraiture, a name that applies collectively to the two museums and their activities. A foundation formed by the late Mr. Reynolds was the largest private contributor to the project. I am not happy with the idea of a single private donor, even a generous one, putting his (or her) name on a national museum, but this new title is so awkward that I don’t see it making the transition into everyday use.

What is felicitous is the renovation of the two museums’ Greek Revival building. With sections dating from 1836 to 1868, the building is once again glorious and now comfortable, too, with repaired tile work and new windows, ventilation and air-conditioning. The open-air courtyard is being glassed over and transformed into a chic year-round facility by the British architect Norman Foster of Foster and Partners, though the courtyard won’t be completed until next year.

All the administrative and curatorial offices have been moved, and formerly blocked windows opened to natural light. The exhibition space has been expanded by about a third, and there’s a new auditorium. The Henry Luce Foundation has sponsored Washington’s first open storage and study center. The new Lunder Conservation Center permits visitors to watch the formerly behind-the-scenes work of conservators caring for the collections through glass walls.

There is a real buzz in the air. Recent acquisitions ranging from of works by Frederic Remington and Oscar Bluemner (whose recent retrospective at the Whitney Museum was a revelation) to Nam June Paik’s wall of flashing TV sets and neon titled Electronic Super Highway: Continental U.S., Alaska, Hawaii (1995), among others, have been installed with great sensitivity.

The plan alternates the National Portrait Gallery’s collection with the Smithsonian American Art Museum collection floor by floor in rough chronological order. This ordering is a step forward but allows the two institutions to remain separate. Arguably, it would make more sense to integrate totally the two collections, which would probably be a bureaucratic impossibility, so I won’t hold my breath waiting for it to happen.

With more than 900 pieces of art on display and another 3,300 in the Luce Foundation Center open storage, it’s hard to choose favorites after only one visit, but several of the paintings in the introductory "The American Experience" gallery are memorable.

If America is about anything, it’s about yearning toward not fully knowable possibilities. That feeling is captured by Edward Hopper’s woman at a window in Cape Cod Morning (1950). Not far away is Georgia O’Keeffe’s celebratory Manhattan (1932) with three roses in tribute floating over an edgy image of New York skyscrapers. A wonderful Hans Hofmann abstraction, Fermented Soil (1965), has a jazzy push-pull energy courtesy of squarish slabs of juicy bright orange and gold paint.

One of the temporary shows focuses on the contemporary Southern chronicler William Christenberry. His photographs of his home state of Alabama often show rural architecture without people, yet let you see their traces in what they’ve done to buildings and landscapes. The show includes his sculpture, paintings and drawings that explore the same subjects as the photos but from different angles.  

Christenberry has also curated the folk art selection, including carvings by several generations of his own family, a nice touch. James Hampton’s idiosyncratic faith produced his Throne of the Third Heaven of the Nations Millennium General Assembly (ca.1950-64), a series of winged thrones and crowns wrapped in miles of silver and gold foil. The work was discovered after the artist’s death in a garage. Now permanently installed in a special niche and gleaming like the gem it is, Hampton’s Throne is sure to dazzle and forms a centerpiece for the weathervanes and other sculptures, paintings, and textiles by self-taught artists.

The National Portrait Gallery’s "America’s Presidents" is a must-see exhibition. It contains Gilbert Stuart’s Lansdowne portrait of George Washington (1796), saved from the auction block by the Donald W. Reynolds Foundation, which donated $30 million for its purchase and display. This iconic painting established the way Americans view Washington. (I also admired Gilbert Stuart’s John Adams (1826) in the American Art Museum, and I thought again about the merging of these two institutions.)

Not far away is one of the most important American photographs ever made, historically and esthetically, the so-called "cracked-plate" Lincoln made by Alexander Gardner in 1865. Once thought to be last photograph made of the president, done in April of 1865, the month of his assassination, it has now been dated several months earlier to February. This change takes away none of the photo’s poignancy. Lincoln’s face is tragically worn and wrinkled as a tortoise’s, yet that strange, powerful physiognomy is also determined with a hint of a smile.

Elsewhere in the Portrait Gallery is an area devoted to the sculptures of Jo Davidson. His terra-cotta of Gertrude Stein (1922-23) imagines the writer hunkered down and looking like a mountain. Being so distinctive and uncompromising a poet, she had to be just that unmovable.

But you don’t have to be dead to be in the National Portrait Gallery. Dawoud Bey’s large color photographs of contemporary teens are one of the best parts of the temporary show "Portraiture Now." In another temporary exhibit, "Americans Now," which features sports and entertainment notables from the past 25 years, you can find composer Philip Glass in one of Chuck Close’s classic cast-paper portraits.

The American Art Gallery has taken special care in installing major pieces. A large niche with velvet drapes frames Albert Bierstadt’s Among the Sierra Nevada, California (1868). Visitors are invited to sit on a bench and contemplate this seven-by -twelve foot canvas, feeling themselves surrounded by the majestic mountains, exactly as in the 19th century.

The decorative arts have been skillfully blended with paintings, sculpture, and drawings. For example, a room filled with paintings of Thomas Dewing’s ethereal women from the turn of the previous century is enhanced by the addition of a Steinway piano that he painted with still more of them. In the same area is the ravishing Peacocks and Peonies, a pair of richly colored stained glass windows by John Lafarge (1882).

Other standouts that impressed me were several, big, powerful black-and-white abstractions by Ab-Ex painter Franz Kline, a room of seascapes by Albert Ryder and a wall of Native American portraits by George Catlin.

In the National Portrait Gallery, I counted four by Alice Neel, including her own self–portrait -- an elderly nude woman with glasses and a paintbrush in her hand seated in a striped chair. It took her five years to paint and challenges a host of taboos. It’s a hoot and a simply great portrait, as are her others.

It’s hard to single out only a few photographs, but an unknown photographer’s fresh-faced Charles Lindbergh standing before his plane, The Spirit of St. Louis (1927), Philippe Halsman’s Audrey Hepburn (1955) looking like a gamin, and Edward Steichen’s Fred Astaire (1927) in top hat and tails are all firmly implanted in my memory. But so are many more.

I’m glad the Smithsonian American Art Museum and the National Portrait Gallery are back and that their mutual home is looking terrific. Walt Whitman once called it, "the noblest of Washington’s buildings." And that’s what it is again.

N.F. KARLINS is a New York art historian and critic.