Adding a scanner to your system can greatly enhance your enjoyment of computing.
With scanner prices drifting down to the $100-$200 range, scanners are now very affordable.
Yes, there are some scanners even less expensive but it has been my experience, a scanner
priced at less than $100 will not offer you the long-term use that a slightly more
expensive scanner will offer. In this article, I'm going to focus on flatbed scanners
although there are multi-function printers that also feature scanning capabilities and
there are wand scanners in which you pass a wand over an image or printed page to digitize
First of all, a scanner is a hardware device that captures an image and converts it into a
digital format that your computer can then display, edit, store, and output. Most scanners
come bundled with a image enhancement software package - frequently a "light" or
stripped- down version of a popular brand.
The image to be scanned can be almost anything - from traditional objects for scanning
such as photographs, pages of text, drawings or illustrations, to even relatively flat
three-dimensional objects like coins, leaves, a swatch of fabric with an interesting
You initiate the scanning process within your image enhancement software program. I use
both Photoshop and Photo-Paint but ArcSoft's PhotoStudio, PaintShop Pro or any one of
dozens of similar, but less expensive image enhancement software programs will do the
job for you. To start the scanning process, you click on File, Import and a list of
hardware capture devices that are installed on your PC is shown. Click on your scanner
name and you're off to the races. At this point, you may be offered the opportunity,
depending upon the software, to increase or decrease the resolution you will obtain
from the scan. The image is scanned and immediately "imported" into your photo
enhancement program. This is where you will "Save As" to give the image a filename
and file it in a folder you select.
Enhancing scanned image
When the image is imported into your image-editing software, you can then edit,
manipulate or enhance the scanned image, using the tools and features of the editing
software for this purpose. For instance, you can use your image-editing software to
correct the brightness and contrast settings of the image, adjust histogram levels,
or apply filters to create special effects.
What kind of scanner do you need?
The type of scanner you need really depends on the kind of work you will be doing
with it. For example, if you want to capture images to place into your Web page,
a company newsletter, or a school project, consider 24bit color flatbed scanners
with 300 x 600 dpi optical resolution.
If you want to scan images to appear in 4-color offset printing, you may need a
30-bit or 36-bit color scanner featuring at least 600-dpi optical resolution. The
increased bit depth enables these scanners to deliver images with more detail and
more overall tones of color.
Finally, if you need to capture 35mm images from slides or filmstrips for publication,
Web sites, or multimedia presentations; or want to archive your collection of
35mm slides, consider a 35mm slide and filmstrip scanner.
Scanners capture images or text for a wide range of applications. Other than a
digital camera, a scanner is the quickest way to get pictures into your computer
and then onto a disk, a CD, a printed page, or sent electronically to a friend
across town or on the other side of the world.
Now grandparents can transfer all of their grandkids' artwork from the refrigerator
door into their PC as wallpaper or screensavers.
For a home business, a color scanner is now a necessary business tool. It's the
perfect device not only for copying and archiving important documents but also for
capturing images to promote and market your business.
Many scanners offer software that mimics a conventional photocopier where you can
lighten or darken an image to be copied (scanned), dial in the number of copies
you want, or resize the image to be copied.
What can do with a scanner ?
Students use scanners to capture images to illustrate term papers or special
projects, to make announcements for school or team sports events, to capture images
for school newspapers and yearbooks.
Business people use scanners to capture images that they can use in presentations,
reports, company newsletters, and brochures. Real estate agents use scanners to
capture images of homes for ads and fliers.
Parents use scanners to capture and save their children's artwork; kids scan found
items, coins, postage stamps, their favorite rock stars from magazines; parents can
scan old family photos to make a digital family tree or family album.
Newlyweds scan their wedding photos to create a multimedia presentation of
Scanners can be used to capture just about any type of image for an endless number
And scanners are used on a daily basis by graphic designers, photographers and
other professionals to capture images for advertising, Web sites, magazines,
brochures, packaging and much more. Scanners are even being used to digitally
preserve valuable documents and manuscripts before they disintegrate.
How do scanners work?
To convert an image to digital information, scanners shine light on the image to
be scanned. The light then bounces back and is captured by a strip of light-sensitive
cells called a charge-coupled device, or CCD.
Since dark areas reflect less light and light areas reflect more light, the CCD
is able to detect the amount of light reflecting from the different parts of the
image being scanned. The CCD then converts the reflected light waves to digital
information. Finally, the scanning software that controls the operation of the
scanner reads this incoming data and reconstructs it into a computer image file.
To capture color images, scanners use a process based on the RGB (Red, Green, Blue)
color model, in which every color is composed of a varying amount of the three
In the RGB model, the absence of white light creates black, the complete saturation
of light creates white (100% of red, green, and blue), and varying amounts of red,
green, and blue create intermediate shades of gray.
For a computer to represent image information in a digital format, the computer uses
units of picture elements, or pixels. An image file, for instance, is simply a
representation of hundreds, thousands, or even millions of pixels arranged in a
grid, and computers record the intensity and color of a pixel in 1 or more bits
of data. The greater the number of bits (or bit-depth) of an image, the more
information it can store. For easy classification, images can be categorized
into single-bit, grayscale, or color.
Bit Depth & Image Quality
The bit-depth of a scanner determines the sharpness of detail and the clarity
of color in your images. A 36-bit scanner, for instance, can sample much more
information than a 30-bit or 24-bit scanner, and the extra information processed
by the 36-bit scanner translates to more vivid color reproduction, smoother color
blends, and more subtle gradations of color approaching lifelike accuracy. A 36-bit
scanner also has a greater dynamic range, giving you more visible detail especially
in the critical shadow and highlight areas of an image.
What resolution should you scan at?
An important feature of a scanner is resolution, which is the amount of detail
recorded by the scanner. Resolution is measured in dots per inch (dpi). The greater
the dpi number, the higher the resolution.
The resolution you select to scan should depend upon the final output. If it is a
funny cartoon or photo you want to e-mail to a buddy to read/see on his/her monitor,
then 72dpi will suffice. Saving it to a JPG file will allow your buddy to see the
image immediately upon opening your e-mail message. If you save as a TIF file, the
recipient will have to use an image enhancement program to view the graphic.
If you are scanning something for printing, then 300dpi should be the mininum scan
It's important to distinguish between optical or true -resolution, and interpolated
resolution which is resolution enhanced through software. Optical resolution is the
amount of information that a scanner's optics can sample or "see" as the CCD moves
vertically across the image. A 24-bit scanner, for example, typically has an optical
resolution of 300 x 600 dpi, while 30-bit or 36-bit scanners typically have optical
resolutions of at least 600 x 1200 dpi.
Interpolated resolution is accomplished in software by surrounding pixels already
seen by the scanner with new pixels that are mathematical averages of the original
pixels. Interpolation can be helpful when enlarging images to retain clarity, or
when scanning black-and-white images or fine line art to produce smoother lines.
Scanning a page of text
One of my favorite uses of my scanner is Optical Character Recognition (OCR) which
eliminates the necessity of having to retype a document.
Text scanning is done through the use of OCR software, which is able to recognize
the shapes, shades and lines that make up individual characters in a text. When the
text recognition process is complete, the user can save the OCR-processed file in
various word-processing formats. The document is then ready for editing. I use
OmniPage Pro for OCRing documents. Frequently I OCR several pages at a time and
OmniPage Pro then attempts to edit the scanned document for individual letter
interpretation errors (which sometimes happens) but I prefer to go ahead and
save the scanned document directly into WordPerfect where I edit the document -
Spell Checker will find anything unusual in the document..
OCR accuracy is measured in terms of accurately identified characters, and a
99% accuracy rate means that 99 out of 100 characters are identified correctly.
Accuracy is dependent, however, on the original document being scanned. For
instance, a typed document yields much better OCR results than a faxed document
or one that's heavily smudged.
If you don't have a scanner, I recommend you go to your office supply store,
Best Buy or CompUSA to look at a broad selection and price range. I assure you
that you will find it an extremely useful tool.