The tone of a graphic is determined by the sum of its details: the style of the typography, the rendering of marks, the voice of the text, the color space, the choice of imagery, and image treatment. These add up to creating an overall mood. Often it may be advantageous for a graphic to appear objective, neutral, and dispassionate. At other times a more sensational, urgent, or emotive approach may best serve your goals.
Sometimes referred to as “aesthetics,” the choice of tone of your graphics should serve both your information as well as your advocacy approach and target audiences, and ideally take cues from your overall communications style and strategy.