I feel strangely rejuvenated,” said the aging photographer Walker Evans after he began shooting pictures with Polaroid’s SX-70 camera. The instant color camera, he argued, meant that for the first time “you can put a machine in an artist’s hand and have him then rely entirely on his vision and his taste and his mind.”

This was just the sort of response Edwin Land had hoped for. Ever since his first, famous snapshot of inspiration in 1943—when his three-year-old daughter Jennifer asked him why she could not see the image immediately—Land had sought “absolute one-step photography.” He introduced his first Polaroid Land camera in 1948, but it would take a quarter of a century and $250 million in development costs to produce what he fervently believed was the ultimate realization of that ideal.

Introduced twenty years ago, in November of 1972, the SX-70 restored the magic to photography for thousands of amateurs and professionals alike—a magic that lay in the mystery of watching its images develop in plain sight, its depth of color, the sense of the print as a jewel-like object—a latterday heir of the daguerreotype.

Edwin Land was at once a very technical and a very romantic man. The SX-70, he claimed, would enable the user to become “an explorer of new countries—not geographical but human countries.” It would awaken “atavistic competences”—a technical way of saying release the artist in everyone.

Each SX-70 print seemed to have what Land called a “depth in its shadows” corresponding to its dozen layers of dyes and other coatings. Polaroid endlessly reprinted a complex schematic diagram of those layers, like something from a geology text. The freedom of the system came from its limitations: like a sonnet or a sonata, the SX-70 picture possessed a firm set of conventions: fixed format, fixed size, fixed palette.

The camera was itself lovely, the last work of the great designer Henry Dreyfuss. “The SX-70 is the most beautiful piece of photographic equipment ever designed,” says the photographer Neil Selkirk, who is more likely to use Hasselblads in his professional work. “The modesty of design is exquisite.” One of the first cameras to include solid-state integrated circuits, it weighed twenty-four ounces and could slip into a sports-coat pocket.

The user comes to take pleasure in the way the SX-70’s “penthouse” view-finder snaps up, like a hiker’s folding cup, the way the little cat-door of the front opens to expel the print, the way the basic folded structure combining saddlelike leather and brushed metal blooms from a flat one by four by seven inches to its full working configuration. Pushing the button ignites a surprising mechanical rumble, like the sudden lowering of airliner landing gear, that with the camera pressed to your eye travels through your cheekbone. And when you are finished, the device snaps