Comparison Epson WorkForce DS-530 vs HP ScanJet Pro 4500 f1

— Tablet. In such scanners, the material to be scanned is placed over a special glass surface, under which a photo sensor moves; the original itself does not move. Flatbed models are the most "omnivorous": they have no restrictions on the thickness of the scanned material and usually allow you to work not only with individual sheets, but also with pages and covers of books and magazines, product labels, etc. Their disadvantage is their significant dimensions — the working surface of the scanner must be no smaller than the supported format (see "Format").

— Lengthy. In pull- through scanners, the photo sensor is stationary, and the scanned material moves relative to it using the feed mechanism. They are much more compact than tablet counterparts (see above), because. of the requirements for the dimensions of the scanner in this case, in fact, only the width remains. Such scanners make it much easier to process long materials; in addition, they are often equipped with automatic document feeders(see below for more details), which makes it much easier to work with a large amount of materials. On the other hand, the feed mechanism can only work with single sheets and will not cope with books and other bulky media.

— Tablet / lingering. The most versatile models that combine the advantages of both designs. They have both an open...ing lid with a glass surface below it, which allows you to work with bulky media (like flatbed models), and a transport mechanism that makes it easier to work with long originals and single sheets (like in broaching designs). They are equipped with two optical sensors and in some cases you can even use both at the same time. The disadvantages of such scanners are significant cost and dimensions, and therefore they are usually used in the professional field, where you often have to scan large volumes of dissimilar materials.

— Slide scanner. These scanners differ from all previous types due to the peculiarities of the processed originals — they are designed to work with transparent materials (slides), such as photographic film. Other scanners equipped with slide modules (see "Slide module") can work with slides, but it is specialized models that provide the best quality.

— Manual. The name of this type is due to the fact that such a scanner must be manually moved over the scanned surface during operation. This is not as convenient as using flatbed or broaching models (see above), especially when working with a large amount of materials. At the same time, the dimensions of hand-held scanners are even smaller than those of broaching ones, while they do not have such a drawback as a limitation on the thickness of the processed materials. Such a device can "take" an image even from a large object that cannot be placed in a flatbed scanner — for example, a box.

The highest resolution of the digital image generated by the scanner during operation. Specified in dots per inch — dpi (dots per inch).

The higher the scan resolution, the higher the resolution of the resulting image will be (with the same size of the source material) and the more accurately small details will be transmitted on it. On the other hand, high resolution noticeably affects the price of the scanner, increases the processing time and the size of the resulting file — despite the fact that the real need for high detail is not always present, and in some cases it is even unnecessary (for example, when processing an image with small artifacts, not visible at low detail). Therefore, when choosing by this parameter, you should not chase high resolution values — you should proceed from the real need and the specifics of the intended use of the scanner.

The simplest modern scanners have a resolution of about 300x300 dpi — this is quite enough for text recognition with an average font size. And in high-end professional models, this figure can exceed 7000x7000 dpi.

The maximum image size that the scanner can process at one time, both horizontally and vertically. You should pay attention to this parameter if you need the exact dimensions of the scanner's working area, down to a millimetre: although standard formats are used to designate these dimensions (see "Format"), in fact the dimensions may differ from them.

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.

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.

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 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.

— 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.

— 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.

— 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.

— 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.

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.