Which art principle is applied to make certain parts stand out in a composition?

Emphasis is the principle of design used to make certain parts of a composition stand out and draw the viewer's attention. Artists create emphasis through contrast in colour, size, shape, texture, or placement, ensuring that the most important element dominates the visual hierarchy.

Rhythm refers to the repetition or alternation of elements to create a sense of visual movement or pattern. Balance concerns the distribution of visual weight across a composition so that it feels stable. Unity is the principle that ties all the elements of a composition together into a coherent whole. While all four are important principles of design, only emphasis is specifically about making certain parts stand out above others.