Raster graphics

Raster graphics is one of the two different kinds of computer graphics. Raster graphics are also called bitmap graphics.

With raster graphics, images are made of many tiny dots. The dots are called pixels.

The individual pixels of a raster image each has its own color.

The problem with raster graphics is that they can look blurry when zoomed in on. Therefore, there is another type of graphics called Vector graphics that work differently.

A computer monitor is a good example of a raster image because it is made of pixels. The number of pixels it has is called the resolution of the monitor. Another example is photographs, which are normally raster images.

Imagine the little smiley face in the top left corner is a raster image. When zoomed in, it might look like the bigger smiley face. Every square stands for a pixel. Looking even closer, you can see the three different pixels at the bottom. Their colors made by adding up the amounts of red, green and blue in each one.

Many printers today use computer languages like Postscript or PCL. These languages are usually based on the other type of computer graphics, called vector graphics.

But to be printed, these images need to be translated into raster graphics first.

This is done by a part called a Raster Image Processor. Most modern printers have those processors inside the printer. Some printers use a special piece of software on the computer to do that job.