It provides the basic information necessary to understanding concepts related to digitizing images with a scanner. Certainly, one can fling a picture on a scanner bed, push the scan button and walk away with a usable image. Most folks scan all the time with no idea of the difference in resolutions, color, the meaning of different image files, or why an image looks the way it does. Yet, knowledge of what is actually occurring and why can make you more effective in manipulating the result. Before this is over, you should understand not only the different file types, but also the basics of resolution and color of digital images.
Color is determined by the bit depth of both the graphic and the monitor.
The screen area of your monitor determines its ppi. It only gets easier from here. We'll look at some of the details below. But, in practice it is only necessary to have a basic understanding of these concepts in order to get good scanning results. The monitor creates the colors you see by emitting varying intensities of red, green, and blue light.