Abstract: Watercolor effects are simulated in computer graphics by defining a brush shape and brush type, selecting a wetness level for the drawing area and, in accordance with the selected wetness level, causing the brush stroke to merely interpolate the brush color with the pre-existing color in the stroked area, create a texture effect of diminishing brush color, or create a smearing effect by interpolating the pre-existing color at a new brush position with that of the previous brush position before interpolating it with the brush color. Apparatus is also disclosed for selecting various brush attributes and brush color parameters.