Product Review
Canon CanoScan LiDE 25 Flatbed Scanner
This slim, snazzy-looking scanner performs basic scanning chores satisfactorily, but look elsewhere if you demand crisp color photographic reproduction. ...more
only £34.04
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High speed barcode scanning!
High speed barcode scanning!
High speed scanning for retail, office or warehouse!
High speed scanning for retail, office or warehouse!
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Scanners Buyers Guide
An imagery to clear perception
A tool for productive pleasure, scanners are considered an essential component in the field of graphic artistry; however, with technology invading every facet of daily life, the merits of a scanner has been noticed to be far-reaching, especially since OCR software came into being. Thus, to process bulk documents by turning them to editable text and to reduce the ennui that bulk typing jobs create; to put up pictures over the internet or to update a photo gallery, no other instrument has been so effective to the humans. But the real problem arises when it comes to choosing one; while an ordinary color scanner is sufficient for home use, a small business finds the portable scanners more beneficial; while a black & white scanner is enough for documentations, a graphic artist or desktop publisher requires specialized photo or slide scanner. This alone proves why a person should stay armed with the proper information; else it would be a sheer case of data mismatch.The Modus Operandi
We all know that scanners capture and convert images to a format that is supported by a computer. An array of photosensitive cells or receptors being the chief component for detecting light reflected off or transmitted through the object being scanned, they measure the light intensity and convert it into electrical charges. A charged-couple device or CCD, as they are technically known as, the job then shifts to the analogue to digital converter or ADC, which then digitizes the analog signals into a form comprehensible by the computer. Each of the cells in the CCD array represents one pixel with a certain number of bits assigned to it. Thus, more the number of bits of information is assigned to each pixel better is the image quality.Additional Information: CIS or Contact Image Sensor technology has entered the field of scanners of late and uses the array of image sensors lying just under the document to be scanned catch the reflected light directly. The CIS scanners are thus cheaper to manufacture; are smaller in size and are more durable. But there's a price to be paid for everything and in this case, it's the image quality. To be considered only when sufficient space is a problem.
The Variety
- Flatbed Scanners: A flat glass plate over the photosensitive array and a cover for the glass – this is how the flatbed scanners are made. The light emitted from under the glass is reflected off the object being subjected to a scan. The light is then picked up by the moving CCD array placed on the scan head. Popular, flexible, monochromatic or color, these are the larger varieties and a must for a higher image quality.
- Sheetfed Scanners: The photosensitive array in this case is a stationary one; it's the page that moves over the array. A good option if huge scanning jobs are in question. An optional component with the sheet fed scanners is an automatic document feeder or ADF. Comes in both monochrome and color and are rather compact in appearance.
- Handheld Scanners: These are the portable varieties with a four or five-inch scan head, but the down side is that several passes are required over a regular sized document for a proper scanning. The software provided usually puts the image pieces back together, but unless gifted with slow, steady hands, they can be real frustrating.
- Slide, Film, and Transparency Scanners: Meant solely for the people in graphics or publishing industry, these are meant for scanning slides, film, negatives and transparencies by transmitting light through them. Most of these scanners have a light source and the scan head on the same side and a very high resolution besides a hefty price tag.
Look before you leap
Unless someone is too brand conscious, checking a few details usually help to procure a good one. The points that need to get checked are as follows:- Bit Depth: Each pixel in an image depicts a certain number of bits and this is known as bit depth. Higher bit depths are a property of good scanners and can differentiate finely between close shades of the same colors to provide a higher image quality. Thus, a bit depth of 30, 32, 36, 42 and 48 are recommended.
- Resolution: Optical and interpolated, it's the first one that holds more importance. A scanner's optical resolution is measured in dots or pixels per inch and is represented as dpi or ppi. More number of pixels thus translates into a better resolution and a sharper image quality and the whole process depends upon the number of CCDs arranged horizontally and vertically in the scan head. Fine details, small fonts and complex lines or edges thus require more optical resolution, which should be 300 and up. In case of interpolated resolution, it's a mathematical algorithm the scanner generates taking into count two true pixels. A more reliable indicator of image quality, higher interpolated resolution is a must if image enlargement is a primary requirement. For scanning slides, negatives or transparencies, 1200 dpi resolution is ideal.
- Dynamic Range / Optical Density: High image quality requires a higher dynamic range or optical density; OD is a measure of how well a scanner captures the tonal range of an image i.e. the gradations from bright highlights to the dark shadows. Measured on a logarithmic scale from 0-4 (zero is pure white and four is pure black), dynamic range is thus defined as the difference between the darkest and brightest optical densities that can be captured by a scanner. The difference is directly proportional to the largeness of the dynamic range.
- Speed: In a world where time is money, more scans per minute means more cash to the wallet. For personal use, a medium speed scanner is all right, but for professional usage, a high speed one is recommended.
- Software: Scanner come bundled with the software i.e. a driver program, color calibration and image-editing software and an optical recognition software or OCR. If bought for a Windows based PC, the driver program is usually TWAIN compatible.
- Interface: Parallel port and pass-through connectors for attaching the printer to the scanner are yesterday's facts; USB and SCSI offer straightforward installation, flexible configuration and faster data transfer. Scanners supporting FireWire are the fastest.
- Warranty: Comparing the warranties before buying is always recommended, both the length and the components it covers. A more extensive warranty for a shorter term is always better in this case.
Key Features
| With over 600 scanners on the market, key features such as Max. Resolution (Hardware), Optical Resolution & Interface are important factors when buying. These features not only effect the performane and quality of the scanner you choose, but also the price. Shown below are price guides for a selection of scanners focusing on the key features: Max. Resolution (Hardware), Optical Resolution & Interface. | |||||||||
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* Taking into account all current scanners on the market the most desirable would be a scanner with 600 x 600 dpi Max. Resolution (Hardware), 600 dpi Optical Resolution and USB 2.0 Interface. The most expensive scanners brand is CONTEXT. If you're looking for a bargain then look out for Sony branded scanners as generally they offer the cheapest scanners.Price Guide
Min £18.68 Avg £2,502.18 Max £74,035.36 SCanners cost anywhere from £18.68 for a basic scanner with few features to around £74,035.36 for a fully featured scanner. Brand Guide
Popular Brands CANON EPSON Mustek Kodak Plustek HP The most popular scanners brand is CANON.
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