Emphasis and Focal Point

Emphasis by Contrast: Emphasis achieved by changing the color, value or color-intensity of the area meant to be the focal point.

A change of hue, value, or intensity can create emphasis by contrast. 

Emphasis by Isolation: Emphasis created by separating an object from a group to draw more attention to it.

Separating one or some from a group calls our attention. This image shows emphasis by contrast and by isolation.

Emphasis by Placement: When the focal point is located in the center or the near-the-center area of a composition.

Even though it is showing multiple subjects, the one in the center calls our attention more than the others.