
A desktop scanner (flatbed scanner) is made of a glass pane, under which a very bright light (usually xenon or cold cathode fluorescent) illuminates the pane and a moving charge-coupled device.
Color scanners usually consist of three rows of charge-coupled device elements with red, green, and blue filters. Then, the media to be scanned (photos, documents, etc.) are placed face-down on the glass pane. The light comes on, and the charge-coupled device and light source move across the pane, "scanning" the entire area.
An image of the media is then visible to the charge-coupled device because of reflected light. Transparent images (film negatives) will not be visible, and require special accessories or dedicated models (film scanners) that illuminate media from the upper side. Today's scanners are generally high-quality, inexpensive, and compact. For more information on scanners, please check out the articles below.
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