Optical density
The maximum optical density of a dark image that the scanner can distinguish from pure black. Optical density characterizes how much of the light falling on the image was reflected (for opaque images) or transmitted (for transparent). The higher the optical density, the less light the object reflects / transmits. Accordingly, the higher the optical density of the scanner, the higher its sensitivity and the better it is suitable for working with dark images.
Mono scanning
The black and white scanning speed provided by the device. Usually, the maximum processing speed for an A4 sheet is indicated, i.e. speed at the lowest resolution. In fact, the speed is usually lower and depends on both the resolution and the size of the original material. The higher the scanning speed, the more convenient it is to work with the scanner; pay special attention to this parameter if you plan to work with numerous black and white images.
Colour scanning
Colour scanning speed provided by the device. In fact, it depends on the selected resolution, colour depth and original dimensions; the characteristics most often indicate the speed for an A4 sheet at the minimum resolution and colour depth, i.e. maximum possible speed. If you only need to scan one or more sheets from time to time, high speed is not too critical, but for working with a large amount of materials, you should look for fast models.
Data transfer
— Wi-Fi. A wireless interface primarily used to build local computer networks. In many respects it is similar to the LAN described below (in particular, it allows using the scanner as a network device), but it compares favorably due to the absence of a cable and the ability to work directly through walls. In addition, relatively recently, Wi-Fi modules have appeared with the ability to directly connect between devices — for example, to control a scanner from a tablet and transfer processed materials to the tablet directly, without creating a computer network. However
scanners with Wi-Fi are quite expensive.
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USB. Universal interface for connecting various peripherals to a computer, including scanners. Today, it is the most common port of this type; at least one USB input is provided by the vast majority of PCs and laptops.
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SCSI. Universal interface for connecting computer peripherals; has a good speed, however, it is much less common than its analogues, besides it is considered obsolete and is gradually being replaced by other standards.
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IEEE-1394. Universal port, in many ways similar to USB (see above). Provides higher speed than the most common USB 2.0, but is much less common.
-LAN. Connector for connecting various devices to a local computer network. A scanne
...r with this interface can be connected as a network device and used with it by any computer on the network, which can be especially useful in offices.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).