Things You'll Need
Stretched watercolor paper
Large watercolor brush
Saucer for mixing
How to Paint a Watercolor Wash. A watercolor wash is a basic technique to establish tone and atmosphere in your paintings. Washes are useful for filling in the background before you start painting your subject. There are three kinds of washes: the flat wash, the graded wash and the variegated wash. You should be comfortable working with washes to get the most out of the watercolor medium.
Stretch your paper. Work flat or tilt your board slightly so your wash can bleed easier.
Choose a large brush that holds a lot of paint and covers a large area. This will make it easier to get an even wash.
Select the color you want for your background and put a generous amount on your palette. Add enough water to get your desired color. Mix well to prevent any globs of pigment transferred to the paper.
Dampen your paper. Start painting at the top of the paper with a broad stroke to the other side. Work quickly so the paint doesn't set into an edge, but blends.
Begin the next stroke by going back to the palette to get more paint and moving your brush across the paper. You can overlap the previous brush stroke a bit. Work down the paper until you reach the bottom. You should have a uniform color all over the paper.
Let your paper dry on a level surface.
Begin as with the flat wash with your paper and brush prepared.
Select the one color you want for the background and mix with water to achieve the desired tone. Start with the loaded brush and a broad stroke across the top.
Lighten the color by adding water to each brush stroke across the page. This will dilute the color and give you a paler color the farther you go down the paper. Continue down until you have a clear brush for clear color at the bottom.
Darken your color by adding more pigment to your wash mixture achieving a darker color with each stroke. Remember to overlap slightly the last stroke to keep the transition smooth.
Dampen and lay your paper flat.
Choose the colors you want to use for a blended wash. You could pick blue and green or blue and umber for painting a landscape of sky and ground.
Drag the brush back and forth in bold strokes overlapping each stroke. Introduce the new color without cleaning the other pigment out of the brush and keep going until your wash is finished. You will have a soft transition between the two colors.
Apply different amounts of pigment and water to the wet surface, achieving a pattern dependent on your brush strokes. You could choose ochre for autumn landscapes or green for woodland landscapes. Experiment with different watercolor papers to achieve different patterns.
Mix your pigment and water in a large mixing area or a small saucer. This prevents you from running out of wash before you finish covering the paper. Keep the amount of water equal so you will have an even wash. When working wet in wet, remember that the water on the paper will dilute your color. Therefore, you may want to use a more concentrated color in your mixing tray. Practice your washes until you get the desired results.