Works of art that express a serious/solemn tone might depict characters that are in straightforward interaction with other characters or with the viewer. Beyond representation, art elements such as slightly muted colors, controlled edges, and careful rendering of form might contribute to a serious/solemn tone.
An artist might impart a serious/solemn tone to a piece due to his or her own solemnity, or the artist might choose to evoke this tone as a reflection of the character(s) or scene being portrayed. A serious/solemn tone might also be adopted to suit a piece that will be shown in a setting that demands solemnity.
Featured: Self-Portrait by Rembrandt Van Rijin.