Sandberg became a prolific portraitist. Lithographs of some of his portraits were published in a volume titled “Gallery of Outstanding Swedish Scholars, Writers and Artists from the Time of Gustav I to the Present” (1835–42). This image of the writer Fredrika Bremer, a pioneer of the Swedish women’s movement, is typical of Sandberg’s portraiture from the period. She appears against a monochrome background, with the focus on her face and individual details of her dress.