by Joel Lukacher, President/CEO, The Mac Store
There are basically three groups of scanners: Consumer, business/SOHO (small office home office), and graphic. Some manufactures only concentrate on graphic scanners, such as Heidelberg, Scitex-Creo, and Screen. Some manufactures only concentrate on Consumer and SOHO scanners, such as HP, and Canon. Some manufactures offer scanners in all three categories, such as Epson, UMAX, and Microtek.
The higher the category the greater the discerning differences between scanners become. You can expect a $20,000 Scitex-Creo EverSmart scanner to produce better scans than a $2500 Epson Expression 1640XL. I would say as a rule of thumb, any scanners under $100 are all about the same. They are built for consumers in mind. They are all slow, noisy, and make great scans for web pages. Scanners priced under $900 are business grade scanners. They are faster, a bit quieter, and have better color range than a consumer scanner. They also sport features like auto document feeders and transparency units' built-in. Business scanners can produce good color for office color inkjet and laser printers. This is because these printers have a small color gamut. Try to use an image from a business scanner in offset printing and you may see muddy brown shadows and soft details.
When a scanner states it has 48bit color, it's only a marketing statement. All scanners are really 24bit-Red/Blue/Green capture devices. That means 16 million colors are available to the scanners eye, or CCD. The additional bits are alpha channel information that some computer applications might use.
A dot per inch, or DPI, is another misunderstood scanner specification. It is rare that a scanner can actually scan 2400x2400dpi, or a 1x1-scanning ratio. The CCD can capture 2400DPI across its width, however the stepping motor which moves the CCD down the bed can only travel at 1200DPI, so they scan at a 1x 0.5-ratio. Many of the higher-end graphic can achieve a 1x1-ratio.
If you always scan images at 100% of size a 300DPI scanner will suit you just fine. If you enlarge your images 400% you will need a 1200DPI scanner. If you scan 35MM transparencies at 800% you will need a 2400DPI scanner. Think of images as "Silly Putty." The final image needs to generally be 266-300dpi. When you stretch a small 2400DPI scan 8 times its original size, the scan becomes 300DPI in full detail suitable for offset reproduction.
When you consider a scanner you must consider its ultimate purpose. Don't try to use a business scanner for commercial printing. And a graphic scanner for little Tommy and Grandma is like a bazooka to a fly.
About the author
Joel Lukacher is the president of The Mac Store, retail Apple Authorized Dealer and Service Provider Plus, in Cooper City, Florida. He has over 26 years of experience in design, printing, pre-press, and computers. After years at Scitex in Massachusetts and as Desktop Systems Manager for large digital pre-presses printing companies locally, he founded Digital Direction, Inc. to assist others in the digital revolution. Success has lead to the construction of The Mac Store, a "Macintosh only" store serving South Florida. He may be reached at firstname.lastname@example.org or (954) 680-9886. © 8/2001 Digital Direction, Inc.