A Buyer's Guide to Flatbed Scanners

Flatbed scanners generally deliver the best composition of quality, flexibility, and usability in scanning. They can be used to scan dissimilar kinds of media, including photos and film (with the supplementary use of a transparency adapter); they can be used to scan text for Ocr and document archiving; and they can be used to scan material of varying sizes and thicknesses -- from small postage stamps to large mechanical blueprints and 3D objects. To decree the flatbed scanner for your needs, this buying guide covers some of the more leading flatbed scanner specifications that you will need to know.

Bit depth and color pass

Practically all scanners today are single-pass types with 48-bit color. Gone are the scanners of yore that required three passes to capture the full Rgb (red, green, blue) color data from an image in individual, painstakingly slow takes. Gone too are 24-bit and 36-bit scanners that proved adequate in the past for delivering up to 68.7 billions of color.

Today's single-pass, 48-bit scanners are fast and can theoretically capture up to 250 trillion colors -- clearly more color than the human eye can distinguish or what monitors and printers can reproduce -- but impressive nonetheless for the promise of compliancy hues as close to life as potential and delivering smoother color gradations. Ignore all but single-pass scanners when shopping for a flatbed, and aim for 48-bit color as well. Reconsider lower-bit models (such as 42-bits) only if your scanner of selection has other specs that a higher-bit counterpart may not have -- such as patented technologies and extra features -- that more than compensate for the lower bit depth of your superior model.

Resolution

The resolution of a scanner determines the level of detail that can be captured; the higher the resolution, the sharper the scan will be. There are two types of resolution: optical and interpolated, with optical resolution being the more leading spec, as it relates to the scanner's actual optics and whole of data that it can sample. The interpolated resolution of a scanner is helpful only in specific applications -- such as scanning line art, where higher resolutions can even out jaggedness and furnish smoother contours.

Most flatbeds today highlight respectable specs for optical resolution, ranging from 2400 dpi to 4800 dpi. Any scanner with such resolution figures would prove a respectable choice, since these specs are more than capable of delivering sharp detail or enlarging images for most print applications. Remember, too, that scanning your images in the full resolution of the scanner is likely to yield file sizes of unmanageable proportions -- without delivery any discernible advantage towards expanding image clarity or quality. So forget the resolution wars of the past when manufacturers trotted out their resolution specs to trump their closest rival. Instead, look for other features today in flatbeds that may be more leading for your needs, or Reconsider the resolution spec Together with these other features when selecting your selection of flatbed.

Ccd vs. Cis Sensor Technology

Image sensors in flatbed scanners can be of two types -- Ccd or Cis. Scanners with Ccd (charge-coupled device) sensors use a system of mirrors and lenses for redirecting light reflected from the traditional document to the Ccd array. Because of the required optics, Ccd scanners are more expensive to furnish and consequent in bulkier scanners, compared to their Cis counterparts. The image capability produced by Ccd scanners, however, is far classic to that produced by Cis scanners.

Cis, or sense Image Sensor technology, is a more recent improvement in which the sensor array lies just under the scanner bed, so that the sensors catch reflected light directly. Since Cis scanners do not need a complicated optical system, they are cheaper to furnish and are smaller in size, resulting in portable, lightweight models that may be prove ideal for cramped desktops. Cis sensors also contain on-board logic that consumes less power than Ccd. But because the on-board logic utilizes space that would commonly be used for the mirrors and lenses in a Ccd to sense light, scans from a Cis scanner are lower in quality. As a result, most population tend to forego the minute savings that can be obtained from a Cis scanner in favor of getting higher-quality Ccd models instead.

Connectivity & Interface

Most consumer-level scanners today will highlight Usb ports -- either Hi-Speed Usb (Usb 2.0) on more recent models, or the earlier Usb 1.1 standard. Hi-Speed Usb is backwards compatible with the Usb 1.1 and has a data replacement rate of 480 megabits per second (Mbps). Higher-end scanner models are likely to contain the FireWire interface as well, allowing scanners to be used in advanced, expert such as audio/video replacement and data storage. Scanners with either Usb or FireWire interface are hot swappable -- which means the scanners can be plugged or unplugged from other devices to which they are associated without having to turn the scanners off and on. Older scanners will contain Scsi or parallel ports, but you shouldn't have to Reconsider these legacy-type models -- unless you are using the scanner to associate to older computers. When shopping for a flatbed, any scanner with a Hi-Speed Usb port should be purchase-worthy, but Reconsider getting a model with dual Hi-Speed Usb and FireWire interfaces to expand your range of potential connections to many other devices and peripherals.

Scan Speed

Speed specifications in flatbeds are hard to decree -- unless the scanner manufacturer provides the specs or the exact conditions in which material is scanned. Scan speeds can run from seconds to several minutes, depending on a wide range of factors. For instance, to correlate scan speed between two comparable models, one will need to know the size of the material being scanned, the resolution setting, the interface being used, and the processing speed and power of the computer to which the scanner is connected. Check speed claims carefully if these are made at all; it may help to do an actual or sample scan with the model of your choice, and see if you are satisfied with the speeds of the preview and actual scans. You could also check to see if your flatbed model has been reviewed in computer magazines or sites and rated for speed, as benchmark tests may give a more full, photo on how fast the scanner runs.

Size of Scan Bed

Most flatbeds today will start out with a proper scan bed size of 8.5" x 11.7", approximating the dimensions of a letter-size image or document. From there, discrete bed-size configurations could come into play, including 8.5" x 14" to accommodate legal-size material, and 12" x 17" for large, tabloid-size scanning. It's commonly a good idea to Reconsider a flatbed with a bed size that's beyond the bare minimum -- in this case, larger than the barebones 8.5" x 11.7". Not only can you fit larger-sized material onto the scan bed, you can also group several smaller pieces on the scan bed and perform batch scans (scanning in groups) to save time and effort.

Dynamic Range

The dynamic range of a scanner measures how well it can capture the tonal range of an image, ranging from the brightest highlights to the darkest shadows. Dynamic range is measured on a scale from 0.0 (perfect white) to 4.0 (perfect black), and the single whole associated with a scanner indicates how much of that range it can tell apart. The minimum and maximum density values that can be captured by a scanner are called Dmin and Dmax, respectively. If a scanner's Dmin was 0.2 and its Dmax was 3.0, then its dynamic range would be 2.8.

While dynamic range is a term often bandied about, in truth the spec is more leading for film scanners used to scan slides, negatives, and transparencies -- as these types of media have a broader range of tones compared to photos, and for which a scanner's higher dynamic range can make a difference. Most flatbed scanners will have a dynamic range of 2.8 to 3.0, but don't be surprised if you can't find it in the specs, as this is not valuable data needed by the median user looking to scan photos or prints.

Software

In selecting the scanner of your choice, Reconsider the software that comes with it. Software will always contain the scanner's own driver or scanning software, as well as a host of complementary programs such as image-editing software like Adobe Photoshop to which the scanned image is delivered; optical character recognition software like Abbyy FineReader Sprint for text scanning and Ocr; color calibration software for higher-end scanner models; and even photo-repair software like Digital Ice. Check for extras as well, such as proprietary or exclusive technologies. For instance, some Microtek dual-bed scanners (a flatbed for scanning photos, a isolate bed for scanning film) contain a technology called E.D.I.T., which features glassless transparency scanning to eliminate artifacts such as Newton Rings and heighten image quality.

The driver or scanning software is a valuable component of your flatbed, as it will decree how legitimately and efficiently you will be able to perform your scans. Good scanning software will offer fast previews, self-operating settings if you wish to simply operations, and plentifulness of image adjustment or enhancement functions to scale images up or down in size, fancy input vs. Output dimensions, set glow and contrast, exact histograms, apply filters, and more. Microtek's ScanWizard scanning software, for instance, offers a proper interface for simplified and self-operating scanning, as well as an advanced interface for more detailed and sophisticated operate of the entire scanning process. Make sure you find out what scanner driver and software bundles are included with your scanner before finalizing your purchase.

Accessories

Flatbeds are able to extend their function and versatility when outfitted with accessories such as a transparency adapter or self-operating document feeder.

The transparency adapter -- which may also be known as a transparent media adapter -- allows you to scan film and transparencies in expanding to the photos that can be scanned by your flatbed. Tmas are installed easily, with the lid of the flatbed scanner removed wholly and the Tma installed in its place. With its own overhead lighting, the activated Tma is able to operate the whole of lighting it shines on the film to be scanned, preventing overexposure of the film and delivering exact image results. commonly included with purchasing a transparency adapter are any whole of film templates or holders to scan discrete types of film, such as 35mm slides, 35mm filmstrips, 4"x5" film, and medium format (6x6-cm up to 6x17-cm panoramic) film. superior color targets for calibrating the scanner to accumulate optimal film scans may also be part of the package.

The self-operating document feeder, or Adf, enhances the document imaging potential of your flatbed scanner. Adfs allow continuous scanning of multi-page documents -- in any place from 50 to 100, or even more pages -- for imaging or Ocr. With an Adf attached to a scanner, you can simply put a sheaf of documents into the Adf, commence the Ocr software for your scanner, and select the proper settings for scanning pages of text. The pages can then be saved either as descriptive or image files for reference and description keeping, or the pages can be ready for Ocr and supplementary text editing.

In choosing on the flatbed scanner of your choice, see if it can accommodate a transparency adapter, self-operating document feeder, or both. The supplementary options may cost a bit more, but the money spent will be worth it if these accessories allow you to do so much more with your flatbed, boosting your efficiency and extending the range of the scanner's functions.

Other components

A final element to Reconsider in your flatbed scanner purchase will be your aid and warranty options. Depending on the price and level of your scanner model, aid and warranty options can be free for a minute period of time, with extended warranty options available if you think you need supplementary security and security. Most manufacturers will offer some form of aid and warranty plan; check to see if these are adequate and fit your needs. The best warranty will cover parts and labor, and a more full, warranty for a shorter term may serve you great than a longer-lasting but watered-down warranty. It may be a good idea to check what sort of technical preserve may be available with your flatbed purchase, and either online support, downloadable drivers, and modernize data can be obtained from the manufacturer's web site.

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