Final answer:
The design principle that guides the audience's attention to the most important element in a scene is Emphasis, achievable through color contrast, scale, or strategic placement within the composition.
Step-by-step explanation:
The design principle that aims to guide the audience's attention and emphasize what holds the utmost significance in a scene is Emphasis. This principle can be achieved through a variety of means, such as differences in color, scale, or isolation of an area of specific subject matter. For instance, artists can create a focal point by using contrasting colors, like placing a string of gold in a field of dark purple, which makes the gold pop out and draw the viewer's attention. Moreover, as witnessed in Francisco de Goya's painting 'The Third of May, 1808', the figure in the white shirt is accentuated by the candle lantern in front of him acting as a spotlight, along with his dramatic stance, highlighting the principle of Emphasis and Subordination within the composition.