Abstract Original Drawing or Painting brown and black 8" x 10" best 1985, vintage

My father, Arthur Jacobson (1924 - 2010), was a noted artist and professor (Arizona State University) with a long career and I have his estate of artworks which includes these small oil pastel "sketches" in preparation for larger oil paintings. He handled the medium in a spontaneous and lively way, capturing the clarity and vibrancy of best the colors. In his later years, he loved abstract, active shapes and line. This one is an original artwork, untitled (brown and black) and is oil pastel and charcoal on watercolor paper, made in 1985, 8 " h x 10 " w. One of a kind, signed and dated by him.