RESEARCH | Digitization

The Library of Congress has digitized more than 8 million books, films, baseball cards, photographs, audio recordings, letters, posters and other rare objects that are available on the library Web site.For researchers, digitization is "opening up a whole new level of scholarship," said Mark Dimunation, chief of the rare books and special collections division at the library.Researchers at Princeton University, for example, studied digital photos of a Gutenberg Bible there and determined that Johannes Gutenberg possibly made his metal type using molds made of packed sand rather than metal -- a significant theory in the development of printing. Scholars using the magnification capability of digital images might compare binding methods and decorations of books of the same approximate age to determine where -- perhaps in what shop -- various volumes were bound.For the first three centuries or so of Western printing, bindings, decorations and text illustrations typically were done by someone other than the printer. The Library of Congress' copy has "rubrications" -- hand-colored letters indicating the beginning of chapters and verses (numbered verses came later) -- but fewer marginal illustrations than some copies.Gerald Wager, head of the rare-book reading room at the library, said the library's copy -- like most of the 160 to 180 Gutenbergs believed printed -- originally was bound in two volumes. But in the 16th century, it was broken into three, most likely because the weight of the vellum made it difficult for the Bible to be moved about by the Benedictine monks who used it regularly in daily monastery life.One of the 13-by-17-inch volumes weighs 18 pounds and the other two each weigh about 14 pounds.When not on display, the volumes are kept in a vault at a temperature of about 50 degrees Fahrenheit. For the digital imaging project, a special cradle was made to hold the Gutenberg Bible horizontally as each volume was photographed from above with a high-resolution digital camera. Cool metal halide lights kept the temperature of the vellum under the maximum 1-degree increase allowed, and each exposure took up to 15 minutes, he said.Most consumer digital cameras are rated at two to four megapixels -- a measure of how much detail the camera captures -- but Octavo's camera is rated at 130 megapixels. To say it another way, while most consumer cameras cannot produce sharp prints larger than 11-by-14-inch images, Octavo's imaging system can produce 6-by-9-foot prints without loss of quality.The "larger" the digital image, the more times it can be magnified for analysis -- down to the pen or brush strokes made by an illuminator or the way the ink hit the page.