Works of art that express a calm/contented tone might depict characters that are in states of centered calm, peaceful in their interactions with one another. Beyond representation, stylistic elements such as harmonious middle-value to light colors, organic shapes, perhaps a subtle blurring of edges might evoke a tone of contentment and peace.
An artist might impart a calm/contented tone to a piece due to his or her own emotional state, or the artist might choose to evoke this tone as a reflection of the characters being portrayed. A calm/contented tone might also be adopted to suit a piece meant for a setting or purpose that demands an expression of peacefulness.
Featured: Madeleine au Bois d'Amour by Émile Bernard.