Colour depth (int.)
Under the internal colour depth is meant the number of shades of the image that the scanner itself can recognize; it should not be confused with external depth, which is the amount of hue transmitted to the computer (see below). Colour depth is expressed as the number of bits of information used to encode data about each colour. The total number of colour shades in this case is 2 to the power of n, where n is the colour depth. So, a 24-bit scanner recognizes 16.7 million colours — which is more than one and a half times more than the human eye, and quite enough for simple everyday tasks. In more advanced professional models, colour depth can reach 96 bits. Although the characteristics of the image transmitted to the computer are described by the external colour depth (which can be less than the internal colour depth), the internal depth, however, also affects its quality: other things being equal, a scanner with a higher internal depth provides more accurate colour reproduction.
Colour depth (ext.)
External colour depth characterizes the maximum possible number of colour shades in the image transmitted by the scanner to the computer. A depth of 24 bits is considered quite enough for non-professional tasks, in more advanced models this parameter can reach 96 bits. For details on colour depths and their relationship, see "Colour Depth (Int.)"
Shades of grey
The number of shades of grey that the scanner recognizes. You should pay attention to this parameter if you plan to actively work with complex black-and-white materials (for example, photographs) — the more shades, the higher the quality of the digitized image. To date, the average is considered to be 512 shades — this approximately corresponds to the capabilities of the human eye. Models with a lower indicator belong to the entry level, more advanced ones “understand” 1024 shades.
LCD screen
The scanner has its own
display. Such displays can vary from simple indicators that display a minimum of service information (selected mode, work process, some errors, etc.) to full-colour touch screens that significantly expand the capabilities of the device. Anyway, the display makes the operation of the scanner more convenient and intuitive.
Power consumption
The maximum power consumed by the scanner during operation. The higher the power, the more energy the scanner consumes, but this only applies to the scanning process itself — in standby mode, power consumption is negligible. And even at the peak in most models, the power is so low that in fact this parameter has practically no effect on electricity bills and is more of an auxiliary value (for example, it is used to calculate the total power of devices connected to an uninterruptible power supply).
