A digital photo scanner is a device for converting photographs into digital images. It is generally used to convert photographs made with film cameras, particularly those created before the advent of digital photography. A high-quality digital photo scanner can convert photo negatives and slides as well as photographic prints. It can also scan documents or any other item that can be placed within its scanning area. While scanners have a wide range of uses, a photo scanner is designed specifically for the needs of the amateur or professional photographer.
The first digital photo scanner was developed in 1957 by computer scientist Russell Kirsch and his team at the U.S. National Bureau of Standards. This was a drum scanner, in which a rotating cylinder is used to record the image with precision sensors. It transmitted the information to a massive computer bank that employed only a fraction of the processing power of modern hand-held computing devices. The very first scan was a photo of Kirsch’s infant son Walden, resulting in a crude but recognizable black-and-white image. In 2003, Life magazine selected this picture as one of the “100 photos that changed the world.”
The drum scanner remained the standard kind of digital photo scanner for the following 30 years. The device was bulky and expensive, so it was rarely available for private use. Drum scanners were used by the newspaper industry as a quick way to reproduce and transmit photographs before the advent of fax technology. Modern drum scanners are capable of high-resolution scans at better quality levels than consumer scanners. For this reason, they are often used by fine-art photographers to reproduce large-format photographs.
The modern digital photo scanner is available in several designs, including small hand-held models and flatbed scanners that employ a glass scanning surface, similar to a copy machine. Some incorporate printers and fax technology into a single image-processing device. These scanners work by moving sensors across the surface of the image or object being scanned. The sensors record color and shape, saving this information as a series of numerical, or digital, values. This information is then transferred to computer programs that can convert it back to an image with a high degree of accuracy.
Many photographers, both amateur and professional, prefer to use a digital photo scanner rather than a general-purpose scanner. These devices are optimized for photographic work. Many include infrared cleaning functions that can automatically detect and remove scratches, dust, and other imperfections. They also have functions to scan negatives or slides, creating a reproduction from the original image rather than from a print, which is itself a reproduction. Some photo scanners are designed to rapidly convert negatives and slides; others can convert motion picture film into digital video.