Resolution Unit - Microtek ScanMaker 4700 User Manual

Settings window
These are single-channel images (8 bits per pixel) that use a color lookup
table containing up to 256 colors. The file size is smaller for images in this
mode. As an initial setting, selecting 256 Colors (Default) uses an Adaptive
palette with Diffusion. If the 256 Colors (Custom) option is selected, the
dialog box will appear.
Palette: The Palette option lets you choose the method for creating the
color palette table. Uniform uses a 6-6-6 fixed color palette table. Adaptive
(default) creates a color palette table from the more commonly used areas
of the color spectrum that appears in the image.
Dither: The Dither option can improve the color quality of the 256-
indexed color image for photographs or continuous-tone images, using a
technique of mixing available colors to simulate missing colors. None
provides no dithering. Pattern uses a structured pattern to simulate
missing colors. Diffusion (default) uses the error diffusion technique to
dither colors and produces the best quality for 256 colors.
Resolution
Resolution is the sampling of image pixel per measurement unit or the
amount of pixel information stored in an image. Together, the image
resolution and dimensions determine the file size of the image, which is
measured in kilobytes (KB) or megabytes (MB).
The resolution of an image is important in determining the quality of the
output image. Resolution is also directly related to file size, and the higher
the resolution, the larger the resulting file size will be.
When dealing with resolution, remember to distinguish between optical
resolution and interpolated resolution.
Optical resolution is the "real" resolution as measured by the scanner's
optics. Interpolated resolution is software-enhanced resolution and can be
useful for enlarging very small images or for printing line art to obtain
superior results.

Resolution Unit

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