Getting the Big Picture

A giant museum camera captures masterpieces

Engineers have spared no effort in recent years trying to reduce the size of everything from computers to portable radios. But Edwin Land, developer of the Polaroid instant camera, has taken a giant step in the opposite direction. At an exhibit at Boston's Museum of Fine Arts this week, Land will show off one of the world's largest cameras, a room-sized blowup of his old invention that in only a minute can make a full-color, full-sized copy of a masterpiece.

Land's idea is not new. The camera obscura (the word camera means room or chamber in Latin) was described by the Islamic scientist Alhazen, who died in A.D. 1039. It consisted of a darkened room with a small opening through which light passed to form an image on the wall opposite the aperture. Nor is using photography to make precise copies of paintings or other objets d'art a recent invention. Art reproductions have long been made by photographing paintings and then enlarging the pictures.

But Land has found a better way. His large-scale camera produces a huge negative, 102 centimeters by 203 centimeters (40 in. by 80 in.), from which an equally big print is made by the Polaroid process. Unlike other large prints that are blown up from a small negative in conventional fashion and lose sharpness in the process, the Polaroid pictures show no graininess. Also, because the image on the original negative is so huge to begin with, conventional enlargement of sections of the negative can produce microscope-like magnifications.

Land first used his huge camera back in 1976 to make and then display for his stockholders a reproduction of his favorite Renoir. The Museum of Fine Arts has used the giant camera more recently to shoot the usually hidden side of a prized possession, a 15th century European tapestry titled The Martyrdom of St. Paul. Despite the best efforts of experts to preserve the side visible to the public, it has gradually deteriorated and faded. But when the museum recently replaced the tapestry's linen backing (a once-in-50-years undertaking), the camera was used to photograph the naked back of the hanging--which had retained much of the vividness of the work's original colors. In the spectacular picture that resulted, every thread is distinct, the colors are brilliant and the tapestry looks three-dimensional.

The device that made this remarkable picture possible is more than a king-size copy of the familiar Polaroid camera. Occupying an otherwise empty room at the museum, the camera is in effect a room within a room, a light-tight box 3.6 meters (12 ft.) wide, 3.6 meters high and 4.8 meters (16 ft.) deep. In addition to a large conventional lens, it contains a Rube Goldbergian arrangement of pulleys, ropes and rollers. While conventional Polaroid cameras are operated from the outside, the three technicians who work Land's invention position themselves inside it.

Shooting a picture is remarkably simple. The tapestry, or any other object to be photographed, is set up exactly 3.9 meters (13 ft.) away from the focal point of the lens, that distance being double the focal length of the lens. Then the tapestry is illuminated with banks of lights (see diagram) while, inside the camera, technicians fine-focus the image on a screen 3.9 meters behind the focal point of the lens. Next, they lower a huge sheet of standard Polaroid negative stock, hold it flat against the screen with a vacuum pump and trip the shutter, thus exposing the negative.

With a whirring of gears, a set of spools turns, unrolling a sheet of printing paper against the negative. The technicians meanwhile spread the patented Polaroid chemical reagent--a viscous mixture they call "goo"--onto both sheets simultaneously. After passing between a pair of rollers, the sandwich of photographic papers is raised, by rope and pulley, toward the ceiling. Then the sandwich is lowered to the floor, and the negative is lifted off, revealing the huge full-color print. "It's nothing but a small Polaroid process made larger," says Technician Peter Bass.

The products of Land's new camera will be revealed to the public at a Museum of Fine Arts exhibit entitled "The Martyrdom of St. Paul: A Medieval Tapestry in Sharp Focus." In addition to the actual Martyrdom, the exhibit will include a life-sized, full-color reproduction of the tapestry's reverse side. It will also display ten 51-centimeter by 61-centimeter (20-in. by 24-in.) reproductions and magnifications of selected segments of the tapestry showing such details as the original stitching and repairs that have been made over the years. The museum will soon use the camera in connection with an exhibit of its world-famous collection of Monets. The full-sized photographs will show several of the impressionist paintings before and after they were cleaned of color-obscuring varnish.

Officials of the museum believe that the camera will open a new dimension in art exhibits, enabling visitors to see far more detail than ever before. Says Larry Salmon, curator of textiles: "We are now able to take the public into that world previously known to art scholars and museum specialists. We can give the public a sense of a work's grandeur as originally perceived by its creators."

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