A-63054 February 2004
9A-23
Dither
—dithering is a way to simulate gray shades and should be used for
scanning photos. It is not recommended for text-only images. Seven options
are available:
• None—also referred to as binary mode. This is the default setting. Always
select this setting for text-only business documents. The other dithering
options significantly increase the image file sizes. Also, for OCR reading, it
is critical that you do not use any of the dithering options because they
decrease the read rate of any OCR system.
• 64 level Bayer Dither
• 16 level Bayer Dither
• 32 level halftone
• 64 level halftone
• Error Diffusion—this option is recommended for photographs because it
uses single pixels. This results in photographs that are more pleasing to the
eye. The other dithering options use a matrix of pixels to simulate grayscale.
• Automatic Dithering—also called automatic separation. Use this option
when you are scanning documents that are a mixture of text and
photographs. When this option is selected, the scanner automatically
recognizes and separates text and photographs. Text is scanned in binary
mode (no dithering) and photographs are scanned using the Error Diffusion
dithering pattern. Automatic separation, however, is not perfect. You will
get better results using Image Segmentation (see the section entitled
“Additional Mask settings for the Scanner 1500 and Scanner 2500”).
NOTES: Noise filter and Automatic Threshold are not available when a
dithering option is selected.
Gamma Correction is not available when None (binary mode) is
selected in Dithering.
When scanning in duplex mode, if Automatic Dithering is selected for
the front Image Setup, it will automatically be selected for the rear
Image Setup.
Enhancement
—also referred to as image emphasis. These selections adjust
the scanning image quality. There are five mode levels: Smooth, None, Low,
Medium, and High. If you select Smooth, the image will be soft with decreased
noise. If you select High, the image will be sharp with clearly displayed thin
lines. The default is “High.”