Normally, this not by accident, it is because of a careful planning based on principles of design.
Usually, the majority of people prefer their lives to have balance, they do not like living on the edge. People want to order in their lives. The same applies to design. Balance in design is concerned with the way a designer distributes the weight on every side of the image. When a designer gives much weight to the right side as to the left, the bottom and the top, this is referred to as symmetry. There is a number of ways to create symmetry. Asymmetrical page in a newspaper would have the right side and the left side of the page balanced. Doing this sometimes is ok; however, having everything balanced in a publication all the time is boring. People like balance in their lives, however they do not like seeing at symmetrical things always.
Occasionally, it is necessary to approach media design of an image via asymmetry. This implies dissimilar but equal visual weight on each side. Thus, you would give one side of the page more weight via visuals, lettering, color etc. This implies that you do not have a page in the sense that all regions of the page are equal in what they contain (Sayre, 106).
In design, balance is achieved via optical weights. This implies that a designer/artist decision on the significance of elements, and their positioning on the page lead the viewer through the page. In other words, the designer guides the viewer’s eyes where he wants them to go- from the most significant to what he thinks is least. The designer knows what he considers most significant elements and those that are not very important and thus he arranges them in such a manner.
The scale is something that works naturally. It is basically arranging spaces in an image in an attractive relationship.