Flatbed scanners
Size ( 8.5”x11”, 11”x17”)
Resolution ( 300 spi, 400spi or 600spi)
True optical resolution VS. interpolated resolution.
Software bundles: Although scanners are provided with their own controller software, most can also be driven from other software packages that provide TWAIN features.
Color depth ( 30 or 36-bit scanners , producing billions of colors)