Microtek ScanWizard Medi, Справочное руководство

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36 Microtek ScanWizard Medi Reference Manual
Resolution Unit
The unit of measurement for resolution is in ppi (pixels per inch) or lpi (lines per
inch). Take note that lpi settings are dimmed if the ruler unit is in pixels.
To choose your resolution unit, click the arrow button next to the box, and
choose your setting from the list box.
• Choose ppi if your scanned images are intended for on-screen display. In this
case, you need not go higher than the target resolution of your monitor. A
higher resolution value will simply increase the file size of your image
without any perceptive improvement in image quality.
• Choose lpi if your scanned images are to be printed. If you choose 1x, for
instance, your scanned image will be printed at 133 lines per inch, resulting
in a 133-dpi image. At 1.5x, the image will be printed at 199.5 dpi; and at 2x,
the image will be printed at 266 dpi. The Custom option allows you to set an
lpi value of your own specification.
In choosing an appropriate lpi value, keep in mind that if the resolution is too
low, the image becomes pixelized, resulting in a deterioration of image quality.
(Pixelization is the process in which the Postscript language uses a single pixel’s
color values to create more than one halftone dot.) Conversely, if the resolution
is too high, the file size becomes unwieldy, and y our file ends up containing
more information than the printer needs, slowing down the file transfer and the
printing process.