Plustek OpticSlim M12 User Manual page 26

Length Encoding (RLE) to achieve compression ratios of approximately
1.1:1 to 1.5:1. RLE is best used with images that have large blocks of
solid colors.
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BMP (Windows Bitmap) - (Bitmap file - also known as a "bump" file) is a
Windows and OS/2 bitmapped graphics file format. BMP is the Windows
native bitmap format. BMP files provide formats for 2, 16, 256 or 16
million colors (1-, 4-, 8-, and 24-bit color).
Auto Processings
Auto Crop - Alternatively you may check the Auto Crop option to have the
scanner program automatically identify the dimensions of the image you scanned
and crop around the edges. The crop shape will be a square or rectangle and it
will not trace the edges of oddly-shaped images. This command can be useful
when scanning smaller images such as photographs.
Auto Deskew - You'll find this option useful when you find the scanned image
slanted. Tick the box of this option and rescan the image; the DigiScan program
will automatically straighten the skewed image(s).
Descreen - applies filtering to images that contain moiré patterns (or
herringbone). A moiré pattern is created from scanning pictures in magazines, or
printed material that use color dithering. The descreen filter is not needed when
scanning original photographs or black and white images and text, but is
recommended when scanning any printed color graphics, such as a page from a
magazine, in order to remove the unsightly interference patterns which may occur.
Scanning Attributes
Size - enables you to alter the scan area. It is preferable to scan the exact area of
the document or image so the file size is the smallest possible and there are no
large blank areas on the page.
Mode – tells the scanner the type of document you are scanning. There are three
settings to choose from:
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Color – scans the document in 24-bit, RGB color. This mode takes the
longest time and uses the most memory but results in the highest quality
images.
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Grayscale – scans images in black and white and can simulate 256
different shades of gray using dithering. This mode is best used when
color isn't necessary for the scanned image since color images take so
much time to scan and process, or when no color printer is available.
Using this mode, even to scan color images, will result in high-quality black,
white, and gray output (the color will automatically be converted to gray).
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Text – is preferable when scanning text documents. It results in clear black
and white documents suitable for printing and faxing.
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