French photographer Henri Cartier-Bresson described photography as the art of capturing the "decisive moment," even though what he probably meant was the decisive hundredth of a second or so.
Still, the metaphor was apt. We've come to think of photographs as instants frozen in time, tiny slivers of reality plucked from the flux of life and immobilized like specimens in a jar.
But what would a photograph look like if, instead of freezing time, the camera simmered it slowly until done?
The result might well resemble the remarkable pictures of Michael Wesely.
On Aug. 9, 2001, Wesely, a German-born photographer based in New York, set up his camera on the terrace of the City Athletic Club overlooking the site where architect Yoshio Taniguchi's dazzling new wing of the Museum of Modern Art was slated to rise. Wesely had been commissioned by the museum to document the project.
After securing the camera firmly in place, Wesely opened the shutter, locked it - and then walked away, leaving the image to percolate slowly on his film for the next two years.
When Wesely finally came back and closed the shutter on May 5, 2003, the marathon exposure of the previous 21 months had recorded both the demolition of the old site and the rising steel superstructure of Taniguchi's new building - as well as ghostly images of the construction, reflections from countless parked cars along 54th Street and the slanting path of the sun across the sky above Manhattan.
Wesely's photograph is one of five very-long-exposure images of the project he made that are on display in MOMA's beautifully reinstalled galleries, which opened yesterday after a three-year, nearly $1 billion renovation of the museum.
His unusual images represent a profound and imaginative rethinking of the traditional processes - and meaning - of photography, an approach that is entirely in keeping with both the medium's history and the startling new directions it may take in the 21st century.
What they are not, however, are literal descriptions of Taniguchi's elegant glass-and-steel design.
Rather, Wesely's pictures re-create the long and complex process that brought the building into being and the steady accretion of elements that went into its construction.
They are, in short, pictures as much about the passage of time as they are about architecture. (Because the exposures were so long, Wesely used very dense filters over the lens to cut down on the amount of light entering the camera.)
"Some things are invisible for physical reasons - they occur too slowly or too quickly to be seen, but other things remain invisible because it would be inappropriate to look for too long," Wesely said during an interview with MOMA photo curator Sarah Hermanson Meister that appears in the catalog for his exhibition.
"In my work I am making people look at the things that are usually almost invisible because they are too slow to be noticed. Of course, this way of taking photographs is, in a way, talking about the decisive moment as well."
Or, he might have added, of refuting it.
In the early days of photography, long exposures were the rule rather than the exception. The slow films often required sitters to remain immobile for several minutes to have their portraits made. Landscapes seemed devoid of people because figures rarely stayed in one place long enough for their images to be recorded.
By the 1890s, faster films and the introduction of small, hand-held cameras allowed photographers to finally capture motion. But the idea of photographs as frozen instants in time didn't really take hold until well into the 20th century.
Wesely's photographs reverse this trend. As Meister writes in her catalog essay, "Exposures of this length are unprecedented in the history of photography, and they allow us to experience the passage of time in an unfamiliar, challenging and rewarding way."
Reading Wesely's long-exposure pictures is a bit like deciphering an archaeological excavation, with bits of the past embedded on the negative in layers like the strata of a temple dig.
In Wesely's picture taken from the Athletic Club terrace, for example, the most distinct elements in the frame are those that didn't change, such as the buildings across the street from the museum and the skyscrapers in the background.
Next are the objects in the sculpture garden in the museum's courtyard, which were among the last to be removed before the new building began to rise. The grid of steel beams supporting the floors of the new structure appears as a series of increasingly transparent lines as each new floor was added.
Above the buildings, diagonal lines mark the daily passage of the sun across the sky and its seasonal displacement against the horizon. And since some days were cloudy, the bright bands are interrupted by darker streaks.
These are images to savor: dense, complex and magical as fine old wine or a dish slow-cooked to perfection.
What: The Museum of Modern Art reopens after three-year renovation and expansion
Where: 11 West 53rd St., New York
Hours: 10:30 a.m. to 5:30 p.m. Saturday, Sunday, Monday, Wednesday, Thursday; 10:30 a.m. to 8 p.m. Friday; closed Tuesday
Admission: $20 adults, $16 seniors, $12 students
Call: 212-708-9400 or visit the Web site at www.moma.org