The document in a flat bed scanner is placed on a glass plate where it is scanned lini-by-line. Therefore it makes no difference in what condition the original is in. This means that even broken originals can be digitalized with no problem at all.

The data depth of the scanner varies between 8 and 12 bit. The data seize is limited to A3 and the maximum resolution is also limited to 600 - 4.800 dpi. There are special scanners that can go up to A0 with a resolution of 600 dpi.

A high optical resolution is recommended for devices with transparent light. With some models, a geometrical precision of 50 to 150 mm can be achieved.

The usage of several objectives in the optical path has the huge advantage that even small originals can be scanned with maximum resolution due to the CCD-line that moves along the complete width.

Attention needs to be drawn to scanners in the low-cost area, which are praised by their huge resolution. These resolutions can only be achieved by interpolated - calculated - resolution whereas the optical resolution is rather low.