Technology Newsletter #10
Tips for Using your Scanner
By Louise Ryan, MSU Extension
Technology Transfer Agent
Scanners are the devices most of us use to get information that is non digital into digital format. Once the information is in digital format we can use it in publications, documents, e-mail it, or use it on the web. In fact we can use the information in any manner that we use digital information from our computer. We will give some ideas you might like to try at the end of this article.
Most people do not have any difficulty using the scanner for simple scans but we will discuss a few things that might help you get better results. A scanner can be used to scan photographs, text, documents, books or small 3 dimensional objects. There are also scanners designed to scan special media types such as slides or film negatives. The scanner will come with software to allow you to operate the scanner from your computer. Many programs, such as Adobe Photoshop also interface directly with your scanner and allow you to import information directly into the program. The software that actually interfaces between the computer and the scanner is called a TWAIN driver. The language the TWAIN driver speaks is a standard, used by all scanner manufacturers which allows programs to interface with any scanner regardless of brand or type.
The Basics
To start your scan you place the thing to be scanned on the scanner bed and then open the software that came with your scanner or the other software program you will be scanning directly into. In programs other than the one that came with your scanner you will most likely find your scanner menu under Import. You may also be asked to select your TWAIN source, especially if you have more than one device that operates with a TWAIN driver. Almost all scanning software will have a menu where you can set options and a box where you can preview what you are scanning.
The first step is always to click on the preview button so you can see what you will be working with. Do not worry at this point if the image
appears unsatisfactory as this preview is low resolution and not always an accurate indicator of what your final outcome will be. Next use your mouse to draw a square around the area you wish to actually scan. You can choose the entire image area or just a portion. When You press scan only the area you have selected will be scanned.
Setting your Options
Resolution: The resolution determines how many dots per inch the scanner will sample. A resolution of 100 dpi would mean that the scanner would sample the image every 1/100 inch. The larger you set the dpi the larger your file size will be and the more disk space the file will take up. This is because the scanner has taken more samples and put them into your file. The actual size of the scanned image, whether it a 4 x 6 photo or a 8 x 10 photo will obviously also have a lot to do with the file size. The larger the image to be scanned the more samples it has to take. The dpi and the original image size will determine the size of the image resulting from the scan. A single pixel of RGB color takes 3 bytes of memory. A gray scale image takes 1 byte and line art which is a simple black or white takes 1 bit. So an 10 x 10 image scanned at 100 dpi (10inch x 100dpi) x (10inch x 100dpi) = 1000 x 1000 pixels or 3000000 bytes of information for RGB color. Set the resolution for your image according to what you will be using your image for.
Normally we scan images for use either on a computer monitor for such things as the Internet or to print in some type of document or brochure.
A PC monitor can not display an image any larger than the monitor screen size but normally we do not want an image large enough to display on the entire monitor. The same is true of print images, normally we do not want a huge image for our document or brochure. In the 2 images below, scan_400 was scanned at 400 dpi and the file size is 1,932 KB, scan_100 was scanned at 100 dpi and has a file size of 193 kb
Scan_400 scan_100
The scan_400 image loads much slower, even to insert in this document while the scan_100 loaded very fast. However, I can not see a significant difference in the images, either one would be acceptable to me.
So why use 300 or 400 dpi? When the images above are shown small there is very little visible difference. The difference becomes visible however, the more we enlarge the image. Below is a section of both images blown up.
Scan_400 scan_100
As you can see, the image scanned at 400 dpi has much better definition because it has more pixels. So if you are going to use your image full size on an 8 ½ x 11 sheet of paper you might want to go 300 dpi. If you want to blow the image way up for something like a poster you will want to use the maximum dpi available to you.
Mode: The mode you use to scan in your document depends on the image itself and what you want to do with the image.
Full Color: The images above were all scanned in full color mode and that is the mode you should choose for a color photo or color copy to use on the web or to send a picture to your friends or relatives in e-mail. You would also want to use this mode for brochures or documents that will be printed in color. Basically use this mode any time the original is in color and you need the final copy to be in color.
Grayscale: An original image that is grayscale should always be scanned in grayscale mode but a color image should be scanned in grayscale when it is to be used in black and white print. The image will be better quality and you will know beforehand what your print image is going to look like. This picture is a color picture that was scanned in grayscale mode.
Black and White: Line art such as simple line drawings or maps and printed documents should be scanned in black and white mode. Below are examples of a line drawing with text scanned with Black and White mode and the in Grayscale mode. The grayscale image looks dirty and the type appears fuzzy because the scanner was trying to read all of the shades of gray in the image, even though there are none.
Things to Do with your Scanner 1. You can use your scanner to keep an inventory for insurance purposes of your personal property. Then you can write the images to CD or put them into a database that you write to a media that can be stored in a safe place for reference in case of a fire or other disaster.
2. You can make a family tree using old photos you have scanned in.
3. You can personalize things like T-shirts, birthday cards, invitations, wrapping paper etc using images you have scanned in.
4. You can make your reports or letters more interesting or colorful using scanned images.
5. You can place small items, such as leaves on the scanner bed and use the resulting scanned image for background on a web page or, using the watermark feature, to use as a background for a printed document.
6. You can scan important documents so that you have a duplicate copy in case of the loss of the original.
7. When there aren’t enough copies of that old photo for everyone you can scan it in and share it.
8. Get creative, the possibilities are almost endless.
Things Not to Do with your Scanner Like most things that are very useful in themselves we can get in trouble if we use them the wrong way. It is illegal to make copies for sale or to distribute to others or to post on your web site of anything that is the intellectual material of someone else or has been copyrighted unless you have the express written permission of the person who’s intellectual material it is or who holds the copyright. If you have doubts about whether you can use or copy something check the law before your do it.
You can find helpful information on copyright law at:www.loc.gov/copyright/
Questions or Comments contact the Van Buren County Technology Transfer Agent
Louise Ryan
ryanl@msue.msu.edu
