Fig. 15. Measures of 3 and 1 balanced by a measure of 2,
the point of balance dividing the space in good proportion.
The balance of three or more masses within a rectangle involves the consideration of two at a time, balancing the pair or pairs with the remaining mass or masses.
In [Fig. 15], masses 1, 2 and 3 are to be balanced within the rectangle. Balancing 3 with 1 gives the balancing point P. Taking 3 plus 1 from the point P, we locate the mass 2 to balance them across the line AB which divides the rectangle in good proportion. The point p then becomes the balancing point for the entire group. Mathematically, 3 plus 1 equal 4; 4 is twice 2; therefore the mass 2 must be twice as far from the point p as the balanced masses 3 plus 1.
Two other combinations might have been worked out with the masses in [Fig. 15]: 3 plus 2, balanced by 1, the mass 1 being placed five times as far from the point p as would the point P. Or 2 plus 1 might have been balanced by 3, in which case the distances would have been equal.
The application of these principles of balance to the problems of typography is largely a matter of influence. The typographer should be guided by them but he need not make mathematical calculations if his eyes be trained to judge relative attraction values so that he can arrange his various masses to secure balance.
Symmetry
When two parts of a design are equal in every respect so that if the design were folded over one-half would superimpose in every detail with the other half, then a state of symmetry exists and the design is said to be symmetrical. The line upon which such a design would be folded, or, in other words, the line which bisects a symmetrical design, is called its axis.
The printed page is often symmetrical with respect to its vertical axis ([Fig. 16]).