The watercolor technique Graded wash is a process for painting large, graded color backgrounds or underpainting for glazing and for smaller areas and objects in a composition using the wet-on-wet technique.
The watercolor is applied in a gentle graduated effect where the color value is darker at the top and gradually gets paler down to the bottom. This is achieved by painting the first few horizontal rows with watercolor paint across the top of the paper or desired area within a composition.
Next, dip the brush in clean water—not paint—and paint a row of diluted color across the bottom of the previous row. For each consecutive row thereafter, continue to dip the brush in water only to paint the next row until the bottom is reached.
By adding only water to the brush after each row is painted, the watercolor gradually gets lighter in value.
In addition to painting a background, the graded wash technique is also used for painting smaller areas and objects within a composition.
For covering large areas, use a one-inch flat brush or an oval “wash brush” (also called a “mop brush”). To paint smaller areas with a graded wash, use a round brush size 10 or larger.
Controlling the brush and the painting speed is important. The wetness of the paper needs to be consistent until the desired area is covered with the graded wash. The tip of the brush should lightly touch the paper and move across the paper in a smooth, horizontal stroke.
When the graded wash is completed, leave the paper tilted at a slight angle on a board or easel until it has dried completely. Then proceed with painting the rest of your watercolor composition.
Use 140 lb cold press archival 100% cotton rag watercolor paper. It is advisable to stretch the watercolor paper first to prevent it from buckling if you plan to cover the paper with a wet-on-wet graded wash. To avoid stretching the paper, I recommend using a watercolor paper block.