Most designers rely on their intuitive sense of proportion in approaching a poster. When our intuition hits a roadblock, however, the principles of proportion can be very helpful in determining the correct division of space within a layout. Let's look at some basic ones now.
The Golden Section
The golden section, discovered by the Greeks in the fifth century B.C., was once referred to as a “key” to proportion. The golden section is a ratio that divides a whole into two segments so that the smaller segment has the same proportion to the larger that the larger has to the whole. This can be expressed algebraically as a:b = b:(a+b). The sides of a golden rectangle have a proportion of 1:1.618.