Under the Desktop: Planning for Scanning

David Morgenstern

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When considering the scanning process, my guess is that most creative professionals think first of software rather than the scanner itself: either the scanner’s software interface or the image-editing application, usually Adobe Photoshop. Sometimes that’s the same thing, thanks to a scanner acquisition plug-in.

Still, your scanner is a complex device, covering the technological bases with mechanical, optical, electrical, and digital hardware components. And then there are drives and scanning software. Each component has its own quirks and it may be useful to keep them in mind when approaching your scanner to begin a job.

While very complicated on the inside, the scanner hardware is so easy to use it’s easy to ignore. You just put the hardcopy on the glass and scan, right? You make sure the settings are correct in the scanner software, and click the button. And then be ready to fix things in your imaging application of choice.

At the same time, a few mindful modifications on the hardware side of the process can improve the quality your raw scans and help you avoid potential pitfalls. Of course, there’s nothing that can be done to the scanner to completely avoid digital touchups, but they can make a difference and save some time to your workflow.

Before launching into the actual tips, let’s take a look at the different components of a flatbed scanner (see Figure 1). Most scanners use a fluorescent tube to shine light on a document that lays on a sheet of glass, often called the platen or bed. Underneath the glass is an assembly packed with a CCD sensor array, bulb, lens and mirrors, pulled along a track by a stepper motor, which moves the package in tiny, precise “steps,” even though it doesn’t climb anywhere.

As we can see from this description, the digital scanning process is much like traditional photography — there are lots of items that are susceptible to dust and dirt. Yet many folks neglect the basics of scanner hygiene.

Look Ma, I Cleaned My Platen
Before cleaning the inside of the scanner, I start by wiping down the lid and the desk around it. Remember that opening and closing the lid will stir up lint and dust in the area that could fall back on the platen after you’ve cleaned it.

The scanner glass should be absolutely clean before beginning a job. Any pieces of dirt, dust, or hair on the platen may show up in the scan and greasy fingerprints can reduce the clarity of some portions of the resulting image. But please don’t use just any old household cleaner or paper towels.

In a previous column I discussed cleaning supplies for monitors. Of course, with a scanner there’s no concern about damaging the glass with cleaning liquids as there is with the anti-glare coatings found on monitors. An alcohol-based spray or liquid cleaner for eyeglasses will work fine for scanners.

Nevertheless, it’s vital when cleaning the platen to avoid scratches, which can reduce clarity or even small refraction artifacts. Paper towels or even a tough rag can scratch the glass surface, and Kleenex brings lots of dust.

In the past, I’ve used scanner “wipes,” soft, lint-free cotton sheets. However, at January’s Macworld Expo, I purchased the just-released Micro Klear Kloth Combo set from Merridrew Industries. The $14.95 two-piece kit includes a 14-inch-square piece of absorbent microfibre cloth (for the less-critical jobs like the case) and a similar-sized piece of optical-grade chamois for screens, glasses, and scanner beds. Each cloth is available separately for $10. They can be rewashed many times, so it’s a more ecological choice than the disposable wipes. The Micro Klear Kloths are so new they’re not yet up on the Merridrew’s online store, but the company said you can order them by phone.

Be very careful with the cleaning liquid and avoid spraying around the sides of the glass. Liquid can seep down the sides of the glass into the inside of the scanner (some are sealed better than others). This can create various artifacts during the scan. It also can damage the white calibration strip on the underside of the glass housing, which could seriously degrade the functioning of the scanner. Some scanner manuals suggest putting the liquid on a piece of cloth and then wiping the glass first. This is a very good idea for cleaners that pour without a sprayer.

After this cleaning process, I put on a pair of cheap, white cotton gloves, like the ones used by the experts on the Antiques Roadshow. These are widely available and cost just a few dollars. This prevents me from spreading fingerprints and dust when I position the hardcopy on the platen.

In addition, it really puts me into a scanning frame of mind.

Actually, some professionals take a larger view towards dust control. Color and prepress consultant Thomas Holm of Pixl suggested to me that an ionized air system can “almost entirely eliminate dust problems,” although he admitted that the cost was about $1,200 for a complete setup.

Consumer reports several years ago liked the $499 list priced Friedrich C-90A single room air cleaner that’s still offered widely. In addition, you can cut down on dust, pollen, and other large particulate environmental gunk with an inexpensive pleated electrostatic microfibre filter for your furnace. This type of filter, a couple of steps up from the usual woven fiberglass filter costs between $10 and $20 each.

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