A Brief Introduction to Scanners by JamieGribowicz

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              A Brief Introduction to Scanners
The flatbed scanner works a little like a photocopier. It has a glass plate under a lid
and a moving light that scans across it. Like a photocopier yo u can make copies of
photos, paper documents, books, magazines, maps, letters, or even objects with a
relatively flat surface like coins, leaves or fabric.




However unlike a photocopier the copy is created in your computer’s memory rather
than as an image on a piece of paper.

This means you can store the images similar to a photo created by taking a picture
with a digital camera, and have the ability to edit it, send it in an e-mail, show it on a
website, or print off copies of it.



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Brief Introduction to Scanners – Silver Surfer Week
Age Concern England 2007
To use the scanner we use software which allows the computer to operate the
scanner and to translate the information that comes from it into an image. This
software is called a TWAIN driver, which is just a programme that allows image
programmes to use any scanner.

Your scanner is connected to the computer and passes electronic data from the
device to the computer to create your image.

To use the scanner, open the lid and place the object that you want to scan on top of
the glass bed, face down on the glass.

Open your image programme and select the option to import an image from the
scanner. The way that this option operates will vary dependent on the software that
you are using. In some instances you will see a scanner icon on the toolbar which
will perform the same function.

There is usually a preview option which makes the scanner produce a low resolution
thumbnail image so you can check out how it is positioned. You can use this
thumbnail image to define whether you just want to scan in a portion of the image or
the document you are producing. For example if you are scanning in an image from
a newspaper, you can mark out the area of the image alone rather than scan in the
whole sheet.

When you are happy, check that you are using an appropriate resolution setting,
press the 'SCAN' button to continue and the scanner will move slowly over the glass
bed to read the image. Ensure that the object is kept stable and doesn't move
during the scan in order to avoid blurring or broken images.

The resolution of a scanned image is measured in DPI (dots per inch) which
measures how many pixels are used in scanning in one inch of your source object.
The larger the resolution you use, the larger the image will appear, and the larger
the image file will be.

To scan in an image which is to be displayed on a computer screen you don't need
to use a particularly high resolution setting - up to 100 DPI should be enough to
ensure that the image is faithfully reproduced. Any more than that and your image
will appear huge and occupy much more memory than is strictly necessary.

If you are scanning in a very small object and want to enlarge it, then use a larger
DPI setting to increase the resolution, but if you are scanning in something you want
to appear smaller than life size on the computer screen reduce the DPI setting.

When you are uploading images to an entry on to a website, for example the ‘Time
Capsule’ website, it is best to ensure that your image is not too large so it can be
displayed easily on a normal sized computer screen. This will mean using a
relatively small image, and so a smaller DPI setting would be more appropriate.

If you want to print the image off, it is a good idea to use a larger DPI resolution
setting. To print an image of a photo, it would be best to use a setting of say 300

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Brief Introduction to Scanners – Silver Surfer Week
Age Concern England 2007
DPI. This is because the printer is capable of printing at a much higher resolution
than the computer screen is capable of displaying images.

Just like the photos taken by a digital camera, the image is stored as a data file,
leaving you free to play around with the image afterwards and make any
adjustments wanted.




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Brief Introduction to Scanners – Silver Surfer Week
Age Concern England 2007

								
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