The digital abilities of a computer get multifold when we have a scanner attached to it. There are two kinds of scanners:
- A flatbed scanner
- A film scanner
A flatbed scanner, also sometimes known as a reflective scanner, is what most people first think of when they consider scanners. It is the most common and the most versatile kind of scanner available in the market today. A flatbed scanner, which resembles a copying machine, can effectively scan any two dimensional flat artwork, photographs, drawings, books, paper and near flat three-dimensional objects.
A flim scanner, also known as the transparency or slide scanner, is specifically designed for scanning transparent film based materials such as 35mm slides or negatives. These scanners work by passing a light through the flim rather than reflecting light off it. Because of their small size, the slides need ot be scanned at a very high resultion. Film scanners are generally more expensive than flatbed scanners and are less versatile.
Resolution refers to the number of pixels the scanner can read in a given area. The amount of detail caotured in the scanning process is determined by the resolution of the scanner. The higher the resolution, the better the quality of the picture and vice versa. Resolution is generally given in dots per inch or dpi. Most flatbed scanners start at 300 dpi whereas the film scanners start at 1000 dpi.
Optical and interpolated resolution: Film and flatbed scanners operate at a specific resolution, called their interpolation. Interpolation can be used for scanning output directly to print to give a better quality when the printed version is enlarged.
Bit depth: Scanners vary in their ability to record colour. The number of colours you capture depends on the bits. While black and white and grayscale are scanned as a 8 bit image, colour photographs are generally scanned at 24 bits and film based materials should be scanned at 30 bits.
Optical character recognition: The technology that allows computers to read text from physical objects, which the scanner use, is called optical character recognition.