Quick answer: To do a watercolor wash, tilt the paper about 15 degrees, mix more paint than you think you need to a tea-like consistency, load a large brush, and paint overlapping horizontal strokes from the top down, reloading as the brush empties and always picking up the wet bead of paint that gathers at the bottom of the last stroke. Keep moving, never go back into a drying area, and let it dry flat. That is a flat wash. A graded wash adds water to the mix with each stroke so the color fades; a variegated wash swaps in a second color partway down; a wet-on-wet wash paints onto pre-wetted paper for soft blooms.
A wash is the first skill in watercolor and the one that keeps coming back. Skies, backgrounds, shadows, a wall, a tablecloth: all washes. Knowing how to do a watercolor wash evenly, without streaks or hard lines where you did not want them, is what separates a painting that looks controlled from one that looks accidental.
This tutorial teaches four kinds of wash in order of difficulty, with numbered steps, the paint-to-water ratios that matter, and a diagnosis section for washes that go wrong. It is written to be usable by a careful adult and by a child painting alongside one; the steps are the same, the paper is just smaller. Families setting up a first kit for a young painter can see what works in the watercolor kits for six-year-olds roundup, and every technique here works with the pan sets those kits include.
What You Need
- Paper: Watercolor paper, 140 lb (300 gsm), cold press. Thinner paper buckles and pools. For kids, a 9×12 pad is plenty; cut sheets in half for practice.
- Board and tape: A piece of foam board, plywood, or a plastic clipboard, with the paper taped down on all four edges using masking or painter’s tape. Taping stops buckling and gives a clean edge.
- Brush: A large round (size 10 to 14) or a 3/4 to 1 inch flat. Bigger holds more paint and means fewer reloads, which means fewer streaks. A size 8 round works for small paper.
- Paint: Pan or tube watercolor. Transparent, staining colors (ultramarine blue, phthalo blue, permanent rose, quinacridone gold) make the smoothest washes. Opaque or granulating colors (cerulean, yellow ochre, some earth tones) are harder to keep even but make interesting textures.
- Water: Two jars, one for rinsing and one clean for mixing.
- Mixing surface: A palette with wells, or a white plate. You need room for a puddle, not a dab.
- Paper towel or a cloth for blotting the brush.
- Something to tilt the board about 15 degrees: a book under the far edge.
The Rules That Apply to Every Wash
- Mix more than you need. Running out mid-wash and remixing is the most common cause of a visible line. A puddle the size of a half dollar covers roughly a 5×7 area; double it for 9×12.
- Tilt the board. Gravity pulls the paint down into a bead along the bottom edge of each stroke. The next stroke picks up that bead and carries it down. Flat paper lets paint pool anywhere; too steep (over 30 degrees) and it runs.
- Keep a bead going. That shiny line of liquid at the bottom of the last stroke is what makes a wash seamless. If it dries, the next stroke leaves a hard edge.
- Do not go back. Once a stroke is laid, leave it. Touching a half-dry area lifts pigment and leaves a blotch.
- Work fast and steady. A 9×12 wash should take under a minute. Hesitation is where streaks come from.
- Dry flat. After the last stroke, lay the board flat so the remaining bead spreads evenly instead of pooling at the bottom edge. Blot the bottom bead with a damp (not dry) brush if it is heavy.
Wash 1: The Flat Wash
One color, one value, perfectly even. This is the foundation.
- Mix the paint. Put a generous amount of pigment on the palette and add clean water until the mix looks like weak tea when you lift the brush. Test on scrap paper; it should be lighter than you expect because watercolor dries 10 to 20 percent lighter than it looks wet.
- Tilt the board about 15 degrees toward you.
- Load the brush fully. Dip to the ferrule and let it drink. Do not blot.
- First stroke. Start at the top left corner (top right if left-handed) and pull one horizontal stroke across the whole width, touching the tape edges. A bead will gather along the bottom of the stroke.
- Reload and overlap. Dip the brush again, then lay the next stroke so its top edge overlaps the bead of the previous stroke by about a quarter of the brush width. The bead flows into the new stroke.
- Continue to the bottom. Reload every stroke or every other stroke. Keep the same speed and pressure. Do not stop to look.
- Finish. At the bottom edge, rinse the brush, blot it until just damp, and touch it to the bottom bead to soak up the excess so it does not creep back up as it dries (a “backrun” or cauliflower).
- Lay flat and leave it alone until completely dry, about 10 to 20 minutes.
A good flat wash shows no stroke marks and no lighter or darker bands. If yours has bands, the usual causes are reloading inconsistently or pausing between strokes.
Wash 2: The Graded (Gradient) Wash
Dark at the top fading to pale or clear at the bottom. Used for skies, water, and backgrounds that recede.
- Mix a strong puddle of your color, about the consistency of coffee rather than tea.
- Tilt the board 15 degrees.
- Lay the first stroke full strength across the top.
- Add water before each new stroke. Dip the brush into clean water (not the paint) and touch it to the edge of the puddle so a little clean water joins the paint on the brush. Lay the next stroke, overlapping the bead.
- Repeat, adding a little more water each stroke. By two-thirds of the way down, you should be using nearly clear water.
- Finish with clean water strokes to carry the bead off the bottom edge, then blot the final bead.
- Dry flat.
If the gradient looks stepped rather than smooth, the water increments were too big. Smaller additions and more strokes fix it. For a reverse gradient (light at top, dark at bottom), simply turn the board upside down and paint it the same way, or start with clear water and add paint each stroke.
Wash 3: The Variegated Wash
Two or more colors flowing into each other. The classic version is a sunset: yellow at the horizon blending up into orange, pink, and blue.
- Mix every color in advance, each in its own puddle at similar consistency. Mixing mid-wash guarantees a hard edge.
- Tilt the board.
- Start with the first color at the top and lay two or three strokes as a flat wash.
- Rinse quickly, load the second color, and lay the next stroke overlapping the bead. The two colors mingle at the join.
- Continue through each color, rinsing between. Where two colors meet, resist blending with the brush; the bead does the blending.
- Finish and dry flat.
Choose colors that mix cleanly where they meet. Yellow into blue makes green at the join, which is fine for a landscape but wrong for a sunset. For sunsets, put a pink or orange band between yellow and blue so the join never produces green.
Wash 4: The Wet-on-Wet Wash
Paint applied to paper that is already wet with clean water. Edges go soft, colors bloom, and the result is loose and atmospheric. Good for skies with soft clouds, misty backgrounds, and the easiest wash for young children because there is no bead to manage.
- Wet the paper evenly with a large brush and clean water. The surface should have a uniform sheen with no puddles and no dry patches. Tilt the board slightly and let excess run off; blot the bottom.
- Wait until the sheen is even but still wet, usually 20 to 60 seconds depending on humidity.
- Touch in color. Load the brush with fairly strong paint (it will dilute on the wet paper) and touch or stroke it on. Watch it spread.
- Add a second color in another area and let the two meet on their own.
- Tilt the board gently in different directions to move the paint if you want, then lay it flat.
- Stop before the paper loses its sheen. Paint added to damp (not wet) paper makes hard-edged blooms. If you want soft, work only while the paper is shiny.
- Dry flat.
Paint-to-Water Ratios at a Glance
| Consistency | Looks like | Used for |
|---|---|---|
| Tea | Pale, transparent | Flat washes for skies and light backgrounds, first layers |
| Coffee | Medium strength, still transparent | Starting value for a graded wash, midtone backgrounds |
| Milk | Thicker, semi-opaque in the puddle | Strong wash areas, wet-on-wet color that will dilute |
| Cream | Thick, little water | Not for washes; detail and dry-brush |
Troubleshooting Washes
| Problem | Cause | Fix next time |
|---|---|---|
| Horizontal stripes or bands | Inconsistent reloading, or pausing between strokes | Bigger brush, bigger puddle, steady rhythm |
| Hard line partway down | Bead dried before the next stroke, or paint ran out and was remixed | Work faster; mix more paint up front |
| Cauliflower or bloom at the bottom edge | Heavy bead left to dry and crept back up | Blot the final bead with a damp brush; dry flat |
| Blotch in the middle | Went back into a drying area | Never touch a stroke once laid |
| Streaks following the brush | Brush too small or too dry | Larger brush, fully loaded |
| Grainy or speckled texture | Granulating pigment, or paper too rough | Use a non-granulating color for smooth washes; cold press over rough |
| Paint pooling in valleys | Paper buckled; not taped or too thin | Tape all four edges; use 140 lb paper |
| Wash dried much lighter than expected | Normal; watercolor lightens 10 to 20 percent | Mix a shade darker than the target |
| Wet-on-wet blooms have hard edges | Paper was damp, not wet, when color was added | Add color only while the surface is shiny |
Practice Plan
Divide a 9×12 sheet into four quarters with tape. In one session:
- Quarter 1: flat wash in ultramarine.
- Quarter 2: graded wash in the same blue, dark at top.
- Quarter 3: variegated wash, yellow to orange to pink to blue.
- Quarter 4: wet-on-wet, blue and a touch of pink dropped in.
Let everything dry, peel the tape, and compare. Repeat the same sheet twice more over a week. The improvement between the first and third sheets is usually dramatic, and the sheets make good backgrounds for later paintings.
Doing Washes With Kids
Six- and seven-year-olds can do flat and wet-on-wet washes well with a few adjustments. Use a quarter sheet or smaller, tape it down for them, and pre-mix the puddles so they only have to load and stroke. Teach the flat wash as “paint a line, dip, paint a line that touches it” and the wet-on-wet wash as “wet the paper, then drop colors in and watch.” Skip graded washes until they can manage the flat wash without going back into it, which usually takes a few sessions. Pan sets in kids’ kits are fine for all of this; the key is a brush big enough to hold water, which many kids’ sets lack, so adding one size 10 round is the single best upgrade.
FAQs
How do you do a flat watercolor wash without streaks?
Use a large brush, mix a big puddle, tilt the paper about 15 degrees, and lay overlapping horizontal strokes from the top down at a steady pace, always picking up the wet bead from the previous stroke. Never go back into an area once painted.
What is the difference between a flat wash and a graded wash?
A flat wash is one even value from top to bottom. A graded wash fades from dark to light by adding water to the brush with each successive stroke.
Why does my watercolor wash have a hard line in it?
The bead at the bottom of a stroke dried before the next stroke reached it, usually because you paused or ran out of paint. Mix more paint and work without stopping.
Should paper be wet or dry for a watercolor wash?
Dry for flat, graded, and variegated washes, where the bead controls the flow. Wet for a wet-on-wet wash, where soft blooms and edges are the goal.
What brush is best for a watercolor wash?
A large round (size 10 to 14) or a 3/4 to 1 inch flat. The more water the brush holds, the fewer reloads and the smoother the wash. Mops and quills are also excellent for large areas.
How long does a watercolor wash take to dry?
Ten to twenty minutes for a single wash on 140 lb paper at room temperature. Humid conditions slow it down. Do not add a second layer until the surface is fully matte and cool to the touch.
Next Step
Run the four-quarter practice sheet three times and washes become automatic. After that, almost every watercolor painting you start begins with one of these four techniques laid down in the first minute. If you are setting up a young painter to learn alongside you, the one thing that matters most is paper that will not buckle and a brush that holds water; the kid-friendly watercolor kit recommendations point out which sets include both and which need a larger brush added.
