Other early 20th-century artists also expanded the repertoire of portraiture in new directions. Fauvist artist Henri Matisse produced powerful portraits using non-naturalistic, even garish, colors for skin tones. Cézanne's relied on highly simplified forms in his portraits, avoiding detail while emphasizing color juxtapositions.[84] Austrian Gustav Klimt's unique style applied Byzantine motifs and gold paint to his memorable portraits. His pupil Oskar Kokoschka was an important portraitist of the Viennese upper class. Prolific Spanish artist Pablo Picasso painted many portraits, including several cubist renderings of his mistresses, in which the likeness of the subject is grossly distorted to achieve an emotional statement well beyond the bounds of normal caricature.[85] An outstanding female portrait painter of the turn of the 20th century, associated with the French impressionism, was Olga Boznańska (1865-1940). Expressionist painters provided some of the most haunting and c...