Painterly is a translation of the German term malerisch, one of the opposed categories popularized by Swiss art historian Heinrich Wölfflin (1864 - 1945) in order to help focus, enrich and standardize the terms being used by art historians of his time to characterize works of art. The opposite character is linear, plastic or formal linear design. The term painterly has been applied to styles such as Venetian painting (as opposed to the Florentine), Baroque (as opposed to Renaissance) and the Rubenistes (as opposed to the Poussinistes).
An oil painting is "painterly" when there are visible brush strokes, and/or a rough impasto surface. This appearance might occur in oils, acrylics, watercolors, gouache, or any medium where a brush is used. Painterly characterizes the work of Pierre Bonnard, Francis Bacon, Paul Gauguin, Vincent Van Gogh, Rembrandt or Renoir, John Singer Sargent and many others. In watercolor it might be represented by John Marin. Linear characterizes the work of Botticelli, Michelangelo or Ingres artists whose works conceal the brushstrokes and depend heavily on drawing, shading, contour and carefully measured proportions.
The Impressionists and the Abstract Expressionists tended strongly to be "painterly" movements. Pop Art and photo-realism emphasize flatness, illusion, and smooth, sublimated brushstrokes. The Pop artist Roy Lichtenstein attempted to make a comment on Abstract Expressionist painterliness when he created images of brush strokes, rendered with comic book style inks and colors, complete with Benday dots and other attempts at imitating commercial reproduction processes on the flat picture plane.
What Rembrandt is to light, Delacroix is to color. Colorists tend to substitute relations of tonality for relations of value and render the form, shadow, light and surface through pure relations of color. "Painterly" art makes strong coloristic use of the many visual effects produced by paint on canvas such as chromatic progression, warm and cool tones, chiaroscuro, complementary and contrasting colors, broken tones, broad brushstrokes, impressionism, and impasto. Jackson Pollock's action paintings of the 1940s and 1950s are more "painterly" than Frank Stella's Hard-edge paintings of the 1960s.
Finally, "painterly" refers to paint, though some forms of sculpture make such use of surface texture resembling brushstrokes that they could almost be called painterly (see Wood as a medium). The application of the term outside painting is a little self-conscious, and may not genuinely help the reader experience the character of Auguste Rodin's surfaces or Richard Strauss's flow of chromatic harmonies. Photography can also be described as painterly.