Size
The first and most basic contrast is size . " A simple but dramatic contrast of size ," says Dair , " provides a point to which the reader ' s attention is drawn . Set in the same style of type , it maintains the exact relationship of the letter to the background . It is only a physical enlargement of the basic pattern created by the form and the weight of the type being used for the text ." The most common use of size is in making the title or heading noticeably bigger than the text — but that ' s only a starting-point .
Weight
The second most obvious contrast is of weight : bold type stands out in the middle of lighter type of the same style . As Dair points out , " Not only types of varying weight , but other typographic material such as rules , spots , squares , etc ., can be called into service to provide a heavy area for a powerful point of visual attraction or emphasis ."
The next two kinds of contrast are the contrast of form and the contrast of structure . It ' s not entirely obvious where to draw a line between these two , since they both have to do with the shapes of the letters .