For less than $100, you can buy a flatbed scanner that will give you decent results. But if you want higher-resolution scans and the ability to scan 35mm slides and color negatives, you'll have to look a bit higher in the price and feature range.
Picking from the crowded desktop-scanner market, Macworld Lab looked at four USB flatbed scanners that had an optical resolution of at least 1,200 dpi and could handle scanning 35mm slides and film: Canon's CanoScan D1230UF and Microtek's ScanMaker 5700, which have an optical resolution of 1,200 by 2,400 dpi; Hewlett-Packard's ScanJet 5470CXI, 2,400 by 2,400 dpi; and the Epson Perfection 1650 Photo, 1,600 by 3,200 dpi.
All the units we tested connect to the Mac via a USB port. The ScanMaker also sports a FireWire port, while the ScanJet includes a parallel port, which is compatible only with PCs. Basic setup for all these scanners was a painless task. Mac-specific documentation from these veteran scanner vendors is thorough and helpful.
As of press time, native OS X support hadn't yet arrived for these scanners, but with the pending arrival of the Carbonized Adobe Photoshop 7, OS X scanner drivers should not be far behind. (Check the vendors' Web sites for the latest driver updates.) All of the scanners we tested worked well in OS X's Classic mode and in OS 9 using the existing drivers.
Scanning software should be easy to use and flexible enough to guide novices through useful presets while allowing experts to change parameters such as gamma curves, shadow and highlight control, brightness and contrast, and color correction. All the scanners' software had these controls, but HP's Precisionscan Pro software and Canon's CanoScan software lead the rest in terms of usability. Precisionscan Pro's interface, for example, felt very Mac-centric, with intuitive controls and menu structures that put the important features in the main window. All the scanners include TWAIN drivers to provide easy access to applications that support this feature, such as Adobe Photoshop, Microsoft Office, and OCR (optical character recognition) software such as OmniPage.
High-resolution scanning isn't the only thing these scanners are good for. All but the CanoScan let you send a scanned image directly to a printer, attach it to an e-mail, run it through an OCR program to convert it to editable text, and even share it on the Web, by using buttons on the scanners themselves. These timesaving features are useful, but you can achieve the same results with a scanner and the appropriate software.
The Trouble with Bits
These scanners offer more than the 24 bits of color (8 bits each for red, green, and blue) you'll find on lower-end models. The CanoScan and the ScanMaker offer 42-bit color depth, while the ScanJet and the Epson Perfection offer 48-bit color depth. For many users, this higher bit depth will add up to one noticeable difference--a doubling of file sizes. This advanced feature captures trillions of colors instead of the 16.7 million you get with 24-bit color. Though you may assume that the more colors captured, the better the scan, this is not always the case. The quality of the scanned image depends on your software and the output device's ability to process information.
Image-editing applications such as Adobe Photoshop and Adobe Photoshop LE can open and manipulate 42- and 48-bit scanned files. But Adobe Elements (bundled with the Epson Perfection) doesn't support 48-bit image files and will convert files down to 24-bit images.
The key advantage of a higher bit depth is that if you capture more data, you'll have much more headroom for editing images that need major corrections to tone or color. If you don't need to make big adjustments using an image editor that supports 48-bit images, we recommend that you save storage space by avoiding this option.
From cropping a scan to removing red-eye, the image-editing software included with these scanners is your ticket to a better final image. The CanoScan and the ScanMaker include Adobe Photoshop LE, and the Perfection bundles Adobe Photoshop Elements. The ScanJet includes ArcSoft PhotoStudio.
If you're scanning low-resolution images for the Web or on-screen viewing, the amount of time it takes to complete the scan is minimal. On the other hand, higher-resolution scans can take much longer because the file is so much larger.
We tested the scanners' speeds by scanning a 4-by-6-inch photograph at a high resolution of 1,200 dpi in 24-bit scanning mode. The scanners' performance varied widely: When connected via USB, the CanoScan, which employs hardware compression to send image data over USB, took top honors, completing our high-resolution time test in 2 minutes and 29 seconds. The Epson Perfection came in second. When connected via FireWire, the Microtek ScanMaker proved to be the fastest contender, with a scan time of only 1 minute and 10 seconds.
Low-end scanners have a limited ability to reproduce high-quality images. Higher-resolution scanners can enlarge an image without losing all its subtle details--this justifies their higher prices.
To judge image quality, we printed scans from these scanners on a high-end graphic-arts ink-jet printer, the Epson Stylus Pro 5000. The quality of the images was superior to that of output from these scanners' lower-resolution counterparts. The Epson Perfection 1650 had the best overall image quality, with good color reproduction, as well as excellent highlights and shadow detail. Our only complaint with the Epson Perfection--and with the ScanMaker--was that the scanned image lacked the sharp, crisp details of the original. The ScanJet and the CanoScan had great image detail, though the images were dark in some areas. The CanoScan's color accuracy beat out that of the ScanJet, which exhibited a subtle red cast. The output from Microtek's ScanMaker 5700 looked soft and the color quality seemed dull when compared with the original image.
Scanning photographic prints and other reflective media is the core job of a desktop scanner. These four scanners are also capable of scanning transparent media such as slides and color negatives. If you're scanning transparency media, you'll need a backlight unit to assist the scanner in capturing data. The CanoScan, Epson Perfection, and ScanMaker have this functionality built into the scanner lids, and the ScanJet comes with an external unit that you place over the flatbed scanner's glass. For simplicity and ease of use, we preferred having the transparency unit built into the lids.
While this dual functionality makes sense, our image-quality tests made it very clear that the resulting scans would need some retouching help from an image-editing program. The Epson Perfection 1650 Photo and HP ScanJet 5470CXI yielded good detail but suffered (along with the other scanners) from brightness and contrast problems. The CanoScan, ScanJet, and ScanMaker scans also showed some noise that affected image quality. If scanning transparencies is an important part of what you do, we recommend that you invest in a slide scanner, which will yield much better results. (For a review of slide scanners, see Reviews, October 2001.)
Macworld's Buying Advice
If you occasionally need to scan transparencies, these scanners will do the job, but expect to do some cleanup work after you scan.
But if you're looking for a speedy midrange scanner that offers excellent color and a strong feature set, we recommend the Epson Perfection 1650 Photo. It not only placed first in our image-quality tests, but also costs less than the other scanners in this roundup.
P>Sidebar: At What Resolution Should I Scan?Being familiar with your scanner's settings and capabilities will help you achieve the best scans. If you don't fully grasp the concept of resolution, your scanned image may end up in one of two camps: a large file with extraneous, imperceptible information or a file that looks distorted when viewed or printed.
The optical resolution of a scanner represents its ability to capture data using only the available hardware. When you start coming across maximum resolution specifications like 12,800 dpi or "unlimited resolution" (especially in the midrange flatbed scanner class), it means the scanner will interpolate--a process of estimating the scan values between two known scan values--to reach that resolution. This allows you to enlarge scans to more than what your optical resolution supports. But because the scanner estimates data where there is none, image quality may suffer. Try to stick with the optical resolution when considering a scanner and its uses. Here are some general guidelines that will help you choose the right scanning resolution.
Web and On-Screen Viewing
The average computer monitor's resolution is less than 100 dpi; therefore, the scanning resolution for images meant only for on-screen viewing should be around 72 dpi (the standard display resolution for a Mac). Anything higher will just use more disk space without improving the quality of the image.
Scanning photos for print is a little trickier. Try sending that 72-dpi scan to your printer, and you'll get a blocky mess. When scanning photos, however, there's a point at which the file size will grow but your resulting output won't look any better.
For the current generation of photo ink-jet printers (the Epson 1280 Photo, for example), plan on scanning at 240 dpi if you'll be printing to matte paper and at 360 dpi if you'll be printing to glossy paper.
You should scan at higher resolutions (such as the ones available in the scanners in this roundup) if you intend to enlarge the print. A good rule of thumb is to scan at 200 dots per printed inch. For example, if you intend to print the scanned image at 600 percent, you would scan at 1,200 dpi.
Text and Line Art
There are no levels of gray involved in scanning text and line art, so the scanner will represent what it scans with either a black dot or a white dot. This is also how a monochrome printer outputs information, so it's best to scan text and line art at your printer's resolution. The size of a dot on the scanned image will correspond to the size of a dot on the printer, minimizing the jagged edges on your output.
Usually, when you scan a transparency or film, you plan to enlarge the image before printing it. In this case, you should scan at 100 to 200 dots per printed inch of the desired enlarged size.<!-Timed scores are in minutes:seconds. We recorded the time it took to scan our 4-by-6-inch photographic test target at1,200 dpi and 24-bit color depth. We tested the ScanMaker using its USB port and its FireWire port. Our panel of experts rated a color print of the scan, printed on an Epson Stylus Pro 5000. We scanned a color negative at1,200 dpi and 24-bit color depth, and we rated the scans on screen. Our test system was a Power Mac G4 500MHz with 512MB of RAM, Mac OS 9.2.2, and Photoshop 6.0.1 installed.--macworld lab testing by james galbraith