Microtek ScanMaker IIG User Manual page 259

Lpi (lines per inch)
The resolution of printed images. Lpi is distinct from dpi, which measures
the resolution of electronic images.
Midtones
The parts of an image between the lighter and darker areas, at around 50%
gray.
Moiré
An undesirable pattern in color printing that results from incorrect screen
angles of overprinting halftones. Moirés usually result when you scan a
halftone or when you scan images taken directly from a magazine (instead
of scanning a photographic original or a transparency).
OCR
Stands for Optical Character Recognition, the process of scanning an
image and converting the image into text format.
Optical resolution
The true resolution of a scanner and is the key factor in determining the
amount of detail visible in an image. Optical resolution is one type of
resolution; the other is interpolated resolution.
Pixel
A unit used by the computer to describe picture elements and to represent
image information in a digital format. An image file, for instance, is simply
a representation of hundreds (or thousands) of pixels arranged in a grid.
Printing methods
The type of printing method you choose should be tailored according to
your scanned image. For instance, low-resolution black-and-white printers
are good for producing text and line art, but they are not suitable for
grayscale. For grayscale, use higher-resolution printers such as the ones
capable of producing 600 to 1200 dpi. To print color images, you can
choose from ink jet/desk jet color printers, dye-sublimation printers, or
printing presses.
Resolution
The level of detail in an image, expressed in dots per inch or dpi. The
greater the dpi number, the higher the resolution and the resulting file size.
There are two types of resolution: optical resolution, and interpolated
resolution.
Appendix J: Glossary J-5