One of the best things about the Baltimore Museum of Art is its main building, a masterpiece of institutional architecture designed by John Russell Pope, the same architect who created the Jefferson Memorial, the National Gallery of Art and the National Archives. As the museum grew over the years, it has been enlarged, and in 1983 and 1994, two wings were added, in contemporary styles.

Unfortunately, they added nothing to the beauty of the whole and are already proving both aesthetically and practically obsolete.

On Sunday, the BMA officially unveils a major renovation to the 1994 contemporary wing, reopening galleries that have been closed since January 2011. The refreshed space is part of a $24.5 million rebuilding campaign that will include both visible and hidden improvements throughout the museum. Unseen by visitors to the refurbished Contemporary Galleries is a new roof. More tangible changes include the removal of two intrusive structural columns, new lighting, the removal of dark glass doors at the entrance, and a paint and flooring makeover that replaced gray walls with white and warmed up the flooring to a natural color.

Doreen Bolger, director of the museum, says the goal was to reinstall the collections “in fresh and engaging ways” and to bring what is on view up-to-date, including display of more recent work. Bolger focuses particularly on improvements to the lighting. A fluorescent system has been replaced with halogen units that can be dimmed. That small improvement means lighting levels can be reduced to safely accommodate photography and delicate works on paper, making it possible to mix up displays with different media.

And that in turn means that monumental works from the 1970s and ’80s can cohabit with complementary works on paper and other smaller pieces, varying the rhythm of exhibitions and introducing variety into the galleries.

The Baltimore Museum of Art in Baltimore, MD. The Contemporary Wing includes works by Andy Warhol among other artists. (Matt McClain/FOR THE WASHINGTON POST)

Also new to the galleries is a black-box space for video, an obligatory medium for any synoptic sense of where contemporary art has been for the past two decades and where it is going today.

The architectural changes, overseen by architect Michael Craft, can’t touch the essential ugliness of the building itself, a concrete structure that feels cold and charmless as you pass out of the older galleries in the Pope building. Connected to the Pope building by a glass-walled passage, the 1994 contemporary building created light issues for the adjacent galleries holding early-20th-century works. By installing a baffle to limit light penetration, it was possible to remove dark glass doors that formerly divided the contemporary wing from the Pope building. It isn’t an ideal solution — the baffle looks rather odd unless you understand its purpose — but it is definitely an improvement.

As always, the ideal is to open up the visitor’s sense of the museum, so that it is easier to see into adjoining spaces and comprehend the basic geography of the space. Long views, a hint of the outside world and natural light, and a clear sense of the progression of spaces seems to help lessen the fatigue many people feel after an hour or more in an art museum.

That helps explain the double purpose in two new works by Sarah Oppenheimer, which are as much architectural features as artistic interventions. Oppenheimer’s “W-120301” and “P-010100” are essentially decorative portals, cut into the walls of the museum. One of them gives a view into the new wing from the old, connecting the visual revolution of the last century to the ongoing explorations of today. The other, installed to give visual access from the main floor of the contemporary wing to the smaller galleries on the third floor, plays with perspective a bit more daringly. By installing a mirror on an angle in the portal, Oppenheimer gives viewers an intriguing glimpse of one of Robert Motherwell’s “Elegy to the Spanish Republic” series hanging in the gallery above.

By removing two large structural columns in the main gallery spaces, those rooms have been opened up. A large I-beam now carries the roof load, and probably only visitors with a keen architectural memory will notice the absence of the two pillars. But the absence is welcome, creating the large, open boxes that are the industry standard for the display of contemporary art.

These small changes to the basic and unfortunate heaviness of the architecture are happy improvements, but they underscore how much more might be done. To really fix this space will require a wrecking ball and an architect more sensitive to how old and new can be happily married. But that wasn’t in the budget and, given that the contemporary wing isn’t even 20 years old, it would be a radical decision to tear it down.

Oppenheimer’s jewellike window works are only two of several new works that are making their debut with the opening of the galleries. Mixed in with a canonical display of art since about 1950 (heavy on Andy Warhol but otherwise thorough and with more than a few gems) are new pieces by Susan Philipsz, Julie Mehretu, Rirkrit Tiravanija, Nari Ward and Sarah Sze, among others.

Of these, Sze’s made the strongest impression. “Random Walk Drawing (Eye Chart)” is a deliriously chaotic piece, with cut paper stretching up a wall and spilling onto the floor. Small lights and a miniature fan give it both shadow and motion, and amplify the sense that Sze has created some kind of self-perpetuating machine. Like an eye chart, its complexity tests vision, inviting ever closer scrutiny. But the game feels deliciously innocent, as if the clippings and scraps on the floor of an artist’s studio had animated themselves into a work of their own.

Baltimore Museum of Art

10 Art Museum Dr.

Baltimore, 443-573-1700, Grand Opening, Sunday, Nov. 18, 11 a.m. – 5 p.m.