|Images in Print|
Raster and Vector Images
There are two main types of Images; Raster and Vector. Vector images are made of solid lines and areas, all based on math, so they can grow or shrink as much as you want and still keep smooth edges and and retain its quality. Raster images are made up of several dots or pixels. Depending on the resolution of the picture/screen the image can have more or less dots. The more dots, the better the image quality. As you increase the size however, the dots don't replicate to retain quality, they stretch. When they stretch you loose image quality. This does not mean Vector is better than Raster. They just both have their uses. Digital artwork, logos and type are best suited to vector where full colour images and scanned images should be raster.
An example Vector and Raster in practice are like using Photoshop and Illustrator. Photoshop is a raster based program and will create raster images. Type done in Photoshop is never as clear as type done in Illustrator or inDesign. In contrast, Illustrator and inDesign are vector based and will create vector images and artwork.
Line art is simple black and white images (or any 2 colours), created from solid strokes. Most people seem to think the term "Line" means straight lines. Line art is really just an image not made up of dots. They are simple and usually print well.
Halftone images are pretty much all images made up of dots. By placing dots of varying shades and colours in certain patterns and different densities you create the illusion of an image. The farther away you look at the dots or the more there are, the more solid a picture looks.