Which colour scheme can create a calm but interesting scene?

Correct answer: Mostly cool colours with a small warm accent

The governing concept is warm–cool colour contrast. Cool colours such as blue and green generally create calmness, while a small warm accent, such as red or orange, attracts the viewer’s eye and prevents the scene from becoming dull. Therefore, mostly cool colours with one warm accent gives both rest and visual interest. Bright red alone is energetic, black alone is severe, and equal amounts of every colour may reduce unity.