Michigan in 3-D
The exhibit, presented by the U-M Bentley Historical Library, brings together new and old 3-D technologies. The basis of the exhibit is the library's collection of original nineteenth-century stereoscopic cards of Michigan people and settings. A stereoscopic card, for those unfamiliar with how one looks or works, is a mount holding two adjacent 2-D photographs of the same subject, taken from slightly different angles. When viewed through a handheld instrument called a stereoscope, or stereopticon, they produce a 3-D image.
To make the 3-D images for this exhibit, each card was scanned, and its two photos were overlapped and aligned to create a single image, which was then processed with red, green, and blue filters. The resulting twenty-first-century stereograph is a tinted and blurry picture whose depth is unlocked when you put on a pair of those flimsy red-and-blue glasses.