Using Digital Scanners
Performing a Scan
Keeping the scanner bed clean
It is important to clean the glass plate on your scanner regularly: Even the smallest specks of dust and dirt will be picked up by the scanner and appear on your image. Use glass cleaner and a soft cloth to remove grime.
Selecting the Correct Mode
Different Modes Explained
RGB Color
All images scanned in this mode are made up of these three colors. All computer monitors use RGB, so it should be used for images that will be displayed on screen - such as Web graphics. Also, RGB can usually be used for images printed to a color inkjet printer.
CMYK Color
Images scanned in this mode are made up of these four colors. Any color image to be printed on a commercial printing press must be saved in CMYK mode. If your scanner does not scan in CMYK, then you will need to convert the image in an image-editing program, afterward.
Grayscale Black & White
This mode creates black & white images with tones of gray.
Lineart Black & White
Lineart does not use color or tones of gray. Because an image scanned in lineart mode will simply appear as a solid black graphic on a white background (or vice versa), it will not require a lot of information. And, as a result, will have a small file size. Therefore, you can afford to scan lineart images at the maximum resolution possible to obtain the best quality image.
Choosing the Correct Resolution
The resolution setting in your scanning software is referred to as dpi. Basically, if an image is scanned at 100% size at 100dpi then it will contain 100 dots (or pixels) of information in every inch. The same image scanned at 100% size at 600dpi will contain six times the amount of information in an inch. A lower resolution means that the image contains less information overall and will be of poorer quality than that of an image scanned at a higher resolution.
What Resolution should I Scan at?
The following examples give some ideal resolutions for scanning images according to their final use. These resolutions are based on the image being used at 100% (the same size as the original) or less. Either increase the resolution or scan the image at a larger size if you are going to make the scan bigger before it is printed:
| 72dpi: | Images and graphics for use on a Web page; |
| 150 - 200dpi: | A color or grayscale picture for output to a color printer; |
| 300dpi: | A color or grayscale picture to be printed on a printing press; |
| 1200dpi: | A lineart black & white image to be used for any purpose. |
File Formats
When saving images, their final use should be considered when selecting an appropriate file format (or type) from the Save As type drop-down menu in the Save As window. The following two examples are the most commonly used in scanning and image editing software:
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