Boosting Your Image with Scanners
By Kim Komando 

It's been a banner year for scanners. A color flatbed scanner that once
cost a few thousand dollars can now be had for a few hundred dollars, or
less. Add to this fact the rising need for color images used in Web page
design and general computing and it's easy to see why a scanner is
quickly becoming an essential component in a computer system.

In the simplest sense much like a copying machine, a scanner takes a
picture of something--a photo, page of text, logo, or artwork--and puts
it inside your computer, where it becomes an image. Scanners can also be
used for copying documents, annotating faxes, and converting a piece of paper
that is outside your PC into something that you can edit using your word
processing program.

Using a scanner, however, is not as easy as using a copying machine.
There's plenty of scanner-specific jargon and sometimes what seems to be
the obvious answer to a scanner question, isn't.

One area of common confusion concerns resolution. The scanner's
packaging often references two resolutions: optical and interpolated (a.k.a.,
enhanced). The optical resolution is the fineness of detail measured in
dots per inch (dpi) that the scanner is capable of producing.

If you need a resolution higher than the optical resolution, the
scanner's software adds extra dots that effectively raises the image's resolution.
This is known as the interpolated resolution. The bottom line is that
the higher the optical resolution, the more accurate the scan will be,
because the software doesn't have to do any guessing.

Most consumer-level scanners scan at either a 300 or 600 dpi optical
resolution. Naturally, you might think that to get the best picture
possible, you should scan at the highest possible resolution. If you're
printing the image on a 720 dpi inkjet printer, you might even need to
enter the interpolated resolution zone. Before you do either, read on
because that's not the way scanning works.

One reason for the obvious confusion is that the term "dpi" is used in
relation to both scanners and printers. These are actually two different
kinds of dpi. For example, if you scan an image in full color (which
I'll cover in a moment) at 200 dpi, each one of those dots can be any one of
millions of different colors. Consider that most color printers have
three or four different color cartridges. This means that each dot that comes
out of your printer can only be one of three or four colors.

What this all boils down to is that the resolution of your scanned image
can be much lower than the dpi capabilities of your color printer and
still produce the same results. In fact, I usually scan all my photographs at
200 dpi--and that's probably too much. Try it yourself and see.

Maybe you're wondering what the harm is in scanning at too high a
resolution. The answer is file size. If you scan the same image at 200
dpi and again at 600 dpi, that second file is going to be nine times bigger
than the first file. That's because it has three times as many dots
across and three times as many dots going down. If you do a lot of scanning and
you scan everything at 600 dpi, your hard drive is going to fill up nine
times faster than it needs to.

Another factor that affects file size is bit depth, or how much color
information can be packed into each scanned dot. While 24-bit color
(alsoknown as millions of colors) is considered full, photo-realistic
color, many scanners now offer 30-bit, 32-bit or even 36-bit color. In
scanner software, these higher setting are often referred to as billions
of colors. Again, you're probably thinking, why not the best for my scanned
photos?

Again, the answer is file size. Each time you raise the bit depth, the
size of the resulting file goes up. So if 24-bit color is considered
photo-realistic, why go beyond that and make unnecessarily big files.
For the typical user, there is no reason. My advice: Stick with 24-bit color
or millions of colors when scanning your photographs.

If you still haven't gotten a scanner, be sure that you buy one that is
TWAIN-compliant. TWAIN is a technology developed by Hewlett-Packard to
allow for direct communication between applications and scanners. Here's
how it works.

Let's say your scanner is not TWAIN-compliant. If you want to put a
scanned photo in a Microsoft Word document, you first launch the software that
came with your scanner. After you scan the photo, you save it to your hard
drive and open it in a program like Microsoft Photo Editor. There, you make a
few adjustments and then save your changes. The final step is to do an
Insert Picture in Microsoft Word and bring in the saved image.

On the other hand, if you have a TWAIN-compliant scanner, you simply do
an Insert Picture From Scanner within Microsoft Word. The picture
automatically gets scanned and popped into Photo Editor. When you're
done making your changes and close the document in Photo Editor, it's
instantly zapped into your Word document. You're not going to get any better
images using a TWAIN-compliant scanner, but it's easy to see how much time you
can save.

When scanner shopping, you're likely to see the new thinner CIS (contact
image sensor) scanners designed to compete with traditional CCD
(charge-coupled device) scanners. Unless desktop space and power
consumption are considerations, stick with a CCD-based unit. By far, CCD
produces the best quality images.

Most times, the software you need to scan and do light editing is
included with a scanner. Depending on the scanner software bundle, you normally
get one or more of the following: the scanner's drivers (needed to run the
scanner with your computer), the scanner software (the software that
lets the scan happen), an image editor (used to modify or clean up an image
after the scan is complete), an image-file organizer (helps you to find
images quickly on your computer's hard disk), and an optical character
recognition (OCR) program (used to translate a page of text into an
editable file).

Consider the software bonuses. You should buy a scanner because of its
performance and then, consider what comes "free" with it. Oftentimes, a
scanner may include a lite-version of the full commercial product. The
programs work but don't have all the features you might want after using
the gadget for a while.

In days of yore, your parents' photographs rotted away in some old
album, slowly developing a yellow tint. When you looked at those yellowed
pictures, you said, "You're old." But with a scanner, you can preserve
all your photos using your PC. And years from now, when your kids look at
you on-screen, they'll say, "You're old." Ain't technology great?

Copyright 1998, The Komando Corporation. All rights reserved. Kim
Komando is a nationally syndicated talk radio host, Computer Editor Popular
Mechanics and author. Visit Kim on the Internet.

While the article refers to "dpi" (dots per inch) it's really an irrelevant
number since most scanned images are going to be used on a computer screen.

Ergo, when scanning, find and change the "units" from dpi or whatever they
are set at and reset it to "pixels"

Most scanners "preview" and then allow you to outline the portion of the
scan bed that you want to use from the final scan.

After you outline the area, check the size in pixels, and determine the
size of the image on the screen where you will use the result.  For
example, if you are going to use it as wallpaper on an SVGA screen, an
800x600 pixel image will exactly fill the entire monitor.

Then "slide" or otherwise adjust the resolution until the scanned size is
near what you want.

This will avoid the heavy losses that you will encounter if you scan an
image and then later "resize" it to fit.
Related issue... may not be news to those who have been color printing for
a while.

Just emptied my first ink cartridges and due to a number of circumstances
knew that the total number of pages that I had printed since the printer
was new was about 350-400 or about 3/4 of a ream of paper, so that
translated into ream of printed paper costing about $70-$80, shocking
compared to the 5000 pages that my $159 toner cartridge supported.

Keep this in mind if you are eyeing a scanner with the thought of printing
a lot of scanned images.