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Introduction
For those who have not worked
with a scanner before, here is a very basic introduction to
get started, a brief overview of how it works, how you would
actually "use" a scanner.
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The flatbed scanner is very
much like a copy machine, to the extent that it has a glass
plate under a lid, and a moving light that scans across under
it. Except that scanners can do great color too, and have more
controls possible. And like a copy machine, a flatbed scanner
allows you to scan photos, paper documents, books, magazines,
large maps, or even 3-dimensional objects (those that don't
have a lot of depth, coins for example), etc. It scans very
much like a copy machine. |
But instead of creating another
piece of paper like a copy machine does, we instead create an
image in memory, which we can do with as we please. We have
acquired a digital image, and we can show it on the screen, or
write a file and email it, or print it, anything we wish.
We must use software to operate
the scanner. Some scanner software can operate by itself, and
some cannot. Most image editor programs (for example Adobe
PhotoDeluxe or JASC Paint Shop Pro or Ulead PhotoImpact, etc)
have a menu at File - Acquire or File -
Import or File - Scanner that you use to
scan an image. Sometimes there is a toolbar Scanner icon too.
This menu starts the scanner's software, called a TWAIN
driver. A fancy word, it is really just another program, but
TWAIN is a software standard that all the scanner
manufacturers agree to use, intended so that all image
programs can operate all scanners. It wasn't always that way,
not so long ago you could use only the one image program that
came with the scanner. Today you have your choice of any.
| TWAIN is often said to be an
acronym for Technology Without An Interesting Name (humor),
but the FAQ at the www.twain.org
organization says it is not an acronym for anything. They say
it instead comes from Rudyard Kipling's line "East is
East, and West is West, and never the twain shall meet"
(The Ballad of East and West, 1889). |
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The TWAIN driver itself is
simply the software provided by the scanner manufacturer to
operate the scanner (the user interface), and it is also the
interface between the graphics program and the scanner
hardware. Twain refers to that separation, now photo editors
dont have to know how to operate scanners. The Twain driver
will always have another name too, Microtek calls theirs
ScanWizard, Umax has two, VistaScan and MagicScan, and HP had
a version called DeskScan, and the current is called
PrecisionScan. The TWAIN driver comes with the scanner, and
knows how to operate this one brand of scanner hardware. Each
scanner manufacturer provides their own TWAIN driver for their
hardware. You can use any image program, but you typically
must use the provided TWAIN driver.
From our human viewpoint, the
TWAIN driver ordinarily has the controls that we use to
specify the scan; we set the mode (Color or B&W or Line
art), we set 100 dpi or 200 dpi resolution, we set the area on
the flatbed glass that we wish to scan, and there are controls
to help correct the tonal quality and color balance of the
scanned image. After the scan completes, the TWAIN driver
transfers the image into the image program memory. That is,
the new image just appears back in the image program. Then you
can tweak the image more, or print it, or save it to a disk
file.
With scanners reducing in price
dramatically over the last few months it has become possible
to add all sorts of art to your web pages. Obviously it will
depend on the scanner you get to what features and which
scanning program you use. You will find that once you set up
your scanning program that some of your other programs
especially graphics programs will then link to your scanner
allowing you to scan directly into them. The software is all
based on the same principles of digital imaging, but each
package looks a little different. Once you become familiar
with scanning, however, you should be able to work with any
scanner.
Once you have the scanned image
in your graphics program you can manipulate and save it as
required.
The following are those
principles and the differing terms used for them in the
software you will find in the Resource Lab.
Type of image being scanned
You need to tell the scanner what type of image is being
scanned. If the picture is in color and you tell the scanner
it is black and white you will get a black and white image.
Resolution
This refers to the quality of the image based on the dots per
inch (DPI). This is the number of dots of color per square
inch of the picture. This is also sometimes called pixels per
inch.
Scale
Scale is the physical size of the picture you are scanning in
relation to the picture after it is scanned. So if the scale
is 100% the image in the computer will be the same size as the
original you are scanning. If the scaling is set to 50% the
digital image will be half the size of the original.
File size
This will tell you how much memory the image file will use
with the current settings. This is important to pay attention
to. If you are saving your file to a disk the image file size
can't be bigger than 1.3mb.
There are some great help sites that discuss the
different problems associated with scanning and here are
a few sites for you.
- A
Few Scanning Tips - This is to help you get off to a
quick start with their flatbed scanners.
- Desktop
Publisher - A good in depth resource of scanning tips
- Real
World Scanning and Halftones book site - Tips, links
and related sources on scanning, as well as excerpts from
the book Real World Scanning and Halftones.
- Scan
help - Tips and Techniques of Image Scanning for the
Desktop Publisher, Multimedia Presentor, and Graphics
Artist. Make sure you scroll down to the free articles.
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