There are many different models of scanners available with costs starting from £100 upwards, but what makes them different? All new scanners now use a CCD (Charged Coupled Device) to scan images, these work with a bar of CCD’s that scans images 1 line at a time. The resolution of the CCD’s is what dictates the maximum resolution for the device, generally the more expensive the scanner, the higher the DPI (resolution). Lower-end scanners can offer a high dpi, but the way the scanner interprets the information can differ vastly between machines of equal specification. Lower-end machines may interpolate the resolution and increase this through software, this can make images lose detail, making them look softer as the dpi is being artificially created. High-end scanners resolution is created with the scanner hardware, keeping the detail in place across all colours in the image. This quality is what makes the difference between consumer and business models. Although most consumer scanners output may look OK, as soon as you zoom in on the detail the difference will be extremely noticeable, along with the lack of detail the colours will look predominately different. Each scanner has its own way to interpret colour from its source, expensive scanners are colour profiled so each scanner reads the information the same, these ICC profiles are created from test sheets of known colours, allowing a highly accurate colour simile to be reproduced each time.
The advantage of a high-resolution scanner are that an image can be enlarged in size whilst holding the information needed to reproduce