Washes The most basic watercolor technique is the flat wash. It is produced by first wetting the area of paper to be covered by the wash, then mixing sufficient pigment to easily fill the entire area. The pigment is applied to a sloping surface in slightly overlapping horizontal bands from the top down. Once complete the wash should be left to dry and even itself out don't be tempted to work back into a drying wash, the results are usually disastrous! A variation on the basic wash is the graded wash. This technique requires the pigment to be diluted.