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, art elements such as harmonious middle-values to light colors, organic shapes, perhaps a subtle blurring of edges might contribute to a tone of contentment and peace.
An artist might impart a calm/contented tone to a piece due to his or her own peacefulness, or the artist might choose to evoke this tone as a reflection of the character(s) or scene being portrayed. A calm/contented tone might also be adopted to suit a piece that will be shown in a setting that demands an expression of tranquility.
Featured: Madeleine au Bois d'Amour by Émile Bernard.