Many designers already know what resolution should be used for print, but do not know why. Similarly, many know what resolution should be used for an image saved for placement on a website, but have no idea that the terminology still used is redundant because the technology has moved on—and that images will change size as a result. And then there are other kinds of resolution: We know about “dots per inch,” but what about “lines per inch”? Are these two connected, and if so, how?

Another resolution number suddenly appears when we consider either our desktop printer, or the imagesetter producing the plates for commercial printing: Suddenly we have a whole combination of numbers, each relating to some kind of resolution: 72, 150, 300, 1440, 3600. All these have a vital part to play.

Resolution can be a very confusing area unless you have an overview of what is going on. Then you can see how all these numbers relate, even though they apply to separate components of the design and printing process, and you will be able to decide exactly what is needed for a particular kind of image, heading for a particular kind of printing, even on a particular kind of paper. And, best of all, resolution issues will never confuse you again.