Image Types; Single-Bit - Microtek ScanMaker IIG User Manual

Image Types

For a computer to represent image information in a digital format,
the computer uses units of picture elements, or pixels.
An image file, for instance, is simply a representation of hun-
dreds, thousands, or even millions of pixels arranged in a grid, and
computers record the intensity and color of a pixel in 1 or more
bits of data. The greater the number of bits, or bit-depth, of an
image, the more information it can store. For easy classification,
images can be categorized into single-bit, grayscale, or color.

Single-bit

Single-bit images are the simplest kind, using just one bit of data
to record each pixel. Single-bit images come in two types: line art,
and halftone.
• Line Art includes anything that is black and white, such as a
pencil or ink sketch. Line Art may also include one-color
images, such as mechanical blueprints or drawings.
• Halftones are reproductions of images that give the illusion of
gray — but only because the black and white dots (or pixels)
comprising the image are arranged in such a way as to fool
the eye to see gray. This is because when the halftone is
printed, dark areas are represented by many dots coming
together, while lighter areas are those with fewer dots. An
example of halftone images would be the pictures you see in
a newspaper.
Line Art
Halftone
Basic Concepts 1-5