| Flatbed scanners generally deliver the best | | | | InterfaceMost consumer-level scanners today |
| combination of quality, flexibility, and | | | | will feature USB ports - either Hi-Speed USB |
| usability in scanning. They can be used to | | | | (USB 2.0) on more recent models, or the |
| scan different kinds of media, including | | | | earlier USB 1.1 standard. Hi-Speed USB is |
| photos and film (with the additional use of a | | | | backwards compatible with the USB 1.1 and has |
| transparency adapter); they can be used to | | | | a data transfer rate of 480 megabits per |
| scan text for OCR and document archiving; and | | | | second (Mbps). Higher-end scanner models are |
| they can be used to scan material of varying | | | | likely to include the FireWire interface as |
| sizes and thicknesses - from small postage | | | | well, allowing scanners to be used in |
| stamps to large mechanical blueprints and 3D | | | | advanced, professional such as audio/video |
| objects. To determine the flatbed scanner for | | | | transfer and data storage. Scanners with |
| your needs, this buying guide covers some of | | | | either USB or FireWire interface are hot |
| the more important flatbed scanner | | | | swappable - which means the scanners can be |
| specifications that you will need to know.Bit | | | | plugged or unplugged from other devices to |
| depth and color passPractically all scanners | | | | which they are connected without having to |
| today are single-pass types with 48-bit | | | | turn the scanners off and on. Older scanners |
| color. Gone are the scanners of yore that | | | | will include SCSI or parallel ports, but you |
| required three passes to capture the full RGB | | | | shouldn't have to consider these legacy-type |
| (red, green, blue) color information from an | | | | models - unless you are using the scanner to |
| image in individual, painstakingly slow | | | | connect to older computers. When shopping for |
| takes. Gone too are 24-bit and 36-bit | | | | a flatbed, any scanner with a Hi-Speed USB |
| scanners that proved sufficient in the past | | | | port should be purchase-worthy, but consider |
| for delivering up to 68.7 billions of | | | | getting a model with dual Hi-Speed USB and |
| color.Today's single-pass, 48-bit scanners | | | | FireWire interfaces to expand your range of |
| are fast and can theoretically capture up to | | | | possible connections to many other devices |
| 250 trillion colors - clearly more color than | | | | and peripherals.Scan SpeedSpeed |
| the human eye can distinguish or what | | | | specifications in flatbeds are hard to |
| monitors and printers can reproduce - but | | | | determine - unless the scanner manufacturer |
| impressive nonetheless for the promise of | | | | provides the specs or the exact conditions in |
| yielding hues as close to life as possible | | | | which material is scanned. Scan speeds can |
| and delivering smoother color gradations. | | | | run from seconds to several minutes, |
| Ignore all but single-pass scanners when | | | | depending on a wide variety of factors. For |
| shopping for a flatbed, and aim for 48-bit | | | | instance, to compare scan speed between two |
| color as well. Consider lower-bit models | | | | comparable models, one will need to know the |
| (such as 42-bits) only if your scanner of | | | | size of the material being scanned, the |
| choice has other specs that a higher-bit | | | | resolution setting, the interface being used, |
| counterpart may not have - such as patented | | | | and the processing speed and power of the |
| technologies and special features - that more | | | | computer to which the scanner is connected. |
| than compensate for the lower bit depth of | | | | Check speed claims carefully if these are |
| your selected model.ResolutionThe resolution | | | | made at all; it may help to do an actual or |
| of a scanner determines the level of detail | | | | sample scan with the model of your choice, |
| that can be captured; the higher the | | | | and see if you are satisfied with the speeds |
| resolution, the sharper the scan will be. | | | | of the preview and actual scans. You could |
| There are two types of resolution: optical | | | | also check to see if your flatbed model has |
| and interpolated, with optical resolution | | | | been reviewed in computer magazines or sites |
| being the more important spec, as it relates | | | | and rated for speed, as benchmark tests may |
| to the scanner's actual optics and amount of | | | | give a more comprehensive picture on how fast |
| information that it can sample. The | | | | the scanner runs.Size of Scan BedMost |
| interpolated resolution of a scanner is | | | | flatbeds today will start out with a standard |
| helpful only in specific applications - such | | | | scan bed size of 8.5" x 11.7", approximating |
| as scanning line art, where higher | | | | the dimensions of a letter-size image or |
| resolutions can even out jaggedness and | | | | document. From there, various bed-size |
| produce smoother contours.Most flatbeds today | | | | configurations could come into play, |
| feature respectable specs for optical | | | | including 8.5" x 14" to accommodate |
| resolution, ranging from 2400 dpi to 4800 | | | | legal-size material, and 12" x 17" for large, |
| dpi. Any scanner with such resolution figures | | | | tabloid-size scanning. It's usually a good |
| would prove a respectable choice, since these | | | | idea to consider a flatbed with a bed size |
| specs are more than capable of delivering | | | | that's beyond the bare minimum - in this |
| sharp detail or enlarging images for most | | | | case, larger than the barebones 8.5" x 11.7". |
| print applications. Remember, too, that | | | | Not only can you fit larger-sized material |
| scanning your images in the full resolution | | | | onto the scan bed, you can also group several |
| of the scanner is likely to yield file sizes | | | | smaller pieces on the scan bed and perform |
| of unmanageable proportions - without | | | | batch scans (scanning in groups) to save time |
| delivery any discernible benefit towards | | | | and effort. Dynamic RangeThe dynamic range |
| increasing image clarity or quality. So | | | | of a scanner measures how well it can capture |
| forget the resolution wars of the past when | | | | the tonal range of an image, ranging from the |
| manufacturers trotted out their resolution | | | | brightest highlights to the darkest shadows. |
| specs to trump their closest rival. Instead, | | | | Dynamic range is measured on a scale from 0.0 |
| look for other features today in flatbeds | | | | (perfect white) to 4.0 (perfect black), and |
| that may be more important for your needs, or | | | | the single number associated with a scanner |
| consider the resolution spec TOGETHER with | | | | indicates how much of that range it can tell |
| these other features when choosing your | | | | apart. The minimum and maximum density values |
| choice of flatbed.CCD vs. CIS Sensor | | | | that can be captured by a scanner are called |
| TechnologyImage sensors in flatbed scanners | | | | Dmin and Dmax, respectively. If a scanner's |
| can be of two types - CCD or CIS. Scanners | | | | Dmin was 0.2 and its Dmax was 3.0, then its |
| with CCD (charge-coupled device) sensors use | | | | dynamic range would be 2.8.While dynamic |
| a system of mirrors and lenses for | | | | range is a term often bandied about, in truth |
| redirecting light reflected from the original | | | | the spec is more important for film scanners |
| document to the CCD array. Because of the | | | | used to scan slides, negatives, and |
| required optics, CCD scanners are more | | | | transparencies - as these types of media have |
| expensive to produce and result in bulkier | | | | a broader range of tones compared to photos, |
| scanners, compared to their CIS counterparts. | | | | and for which a scanner's higher dynamic |
| The image quality produced by CCD scanners, | | | | range can make a difference. Most flatbed |
| however, is far superior to that produced by | | | | scanners will have a dynamic range of 2.8 to |
| CIS scanners.CIS, or Contact Image Sensor | | | | 3.0, but don't be surprised if you can't find |
| technology, is a more recent development in | | | | it in the specs, as this is not critical |
| which the sensor array lies just under the | | | | information needed by the average user |
| scanner bed, so that the sensors catch | | | | looking to scan photos or prints.SoftwareIn |
| reflected light directly. Since CIS scanners | | | | selecting the scanner of your choice, |
| do not need a complex optical system, they | | | | consider the software that comes with it. |
| are cheaper to produce and are smaller in | | | | Software will always include the scanner's |
| size, resulting in portable, lightweight | | | | own driver or scanning software, as well as a |
| models that may be prove ideal for cramped | | | | host of complementary programs such as |
| desktops. CIS sensors also contain on-board | | | | image-editing software like Adobe Photoshop |
| logic that consumes less power than CCD. But | | | | to which the scanned image is delivered; |
| because the on-board logic utilizes space | | | | optical character recognition software like |
| that would normally be used for the mirrors | | | | ABBYY FineReader Sprint for text scanning and |
| and lenses in a CCD to sense light, scans | | | | OCR; color calibration software for |
| from a CIS scanner are lower in quality. As a | | | | higher-end scanner models; and even |
| result, most people tend to forego the slight | | | | photo-repair software like DIGITAL ICE. Check |
| savings that can be obtained from a CIS | | | | for extras as well, such as proprietary or |
| scanner in favor of getting higher-quality | | | | exclusive technologies. |
| CCD models instead.Connectivity & | | | | |