Emphasis or dominance referes to visual hierarchy in design and provides a focal point for the whole creation. When nothing is dominant, the viewers aren't sure what the designer is trying to say. The three stages of dominance are:
1. Dominant
The element is placed in a foreground, given a primary position i.e. most emphasis and visual weight.
2. Sub-dominant
The element is placed in a middleground, given a secondary position.
3. Sub-ordinate
The element is placed in a backround, given a tertiary position i.e. least emphasis and visual weight.
In the example below the trees are primary element, the house is a secondary element and the mountains are tertiary element.