User`s guide

Glossary G-3
Density
The degree of opacity of a photographic image on paper or film.
DPI
Stands for dots per inch, the measure of resolution . The greater the dpi number,
the higher the resolution.
Exposure
The amount of light in an image. The exposure of an image can be changed by
increasing or reducing available light.
File format
The way a graphic file is saved. Several file formats are available for use, and
each one has its own advantages and disadvantages. The most popular file
formats include TIFF, PICT, EPS, and PCX. TIFF is the most widely used file
format.
Filters
Tools that allow you to apply or create special effects to your images. Filters in
your scanning software include Blur/Blur More/Gaussian Blur, Sharpen/Sharpen
More, Emboss, and Enhance Edges.
Gamma
The contrast affecting the mid-level grays or midtones of an image. Adjusting the
gamma of an image allows you to change brightness values of the middle range
of gray tones without dramatically altering the White and Black points.
Grayscale
An image type that contains more than just black and white, and includes actual
shades of gray. In a grayscale image, each pixel has more bits of information
encoded in it, allowing more shades to be recorded and shown. 4 bits are
needed to reproduce up to 16 levels of gray, and 8 bits can reproduce a photo-
realistic 256 shades of gray.
Halftone
A type of single-bit image composed of a pattern of black dots that fool the eye
into seeing shades of gray. Examples of halftone images are the pictures you see
in a newspaper. These images usually look very coarse.