Creating a smooth, beautiful flat wash might look simple, but it often trips up beginners. If you’ve been painting skies or sunset scenes and can’t seem to achieve that clean, even wash, you’re definitely not alone.
As Kerrilyn Cheah often explains, mastering flat washes is one of the foundations of strong watercolor technique.
In this article, Kerrilyn Cheah will walk you through how she paints flat washes, the common mistakes to avoid, and the proper techniques that will help you build confidence and achieve stunning, streak-free results.
Contents
Why Flat Washes Matter in Watercolor Painting
Flat washes are everywhere in watercolor paintings. They’re beneficial when creating backgrounds, like soft skies or warm sunsets.
A flat wash simply means applying an even layer of color over a large area without streaks or blotches. That smooth finish gives the artwork a polished, professional look.
But while it may sound easy, getting it right takes a bit of planning and the right tools. They show what can go wrong—and how to avoid it.
Common Mistakes Beginners Make
Let’s start with the most significant reasons a flat wash goes wrong. They’ve been there and want to help others avoid the same mistakes.
Mistake 1: Using the Wrong Brush Size
This one made a huge difference for them. Using a small brush is a big problem if someone is covering a large area. They remember having to reload paint from the palette again and again.
And while doing that, parts of the paper dried too fast. This left behind harsh, dry brush strokes.
Mistake 2: Not Preparing Enough Paint
Another common mistake is running out of paint halfway through the wash. They used to think they could just mix more when needed.
But that often created problems. The second batch of paint never matched the first—either too diluted or too strong. The wash ended up patchy and uneven.
Once, their second mix was so diluted that they had to paint over it again, trying to fix it quickly.
But by then, the first layer had already started drying. They had to prepare a third, more saturated batch than the first two. That just made the whole wash look inconsistent.
Mixing paint during the wash also eats up time. While someone is rushing to mix more, the first strokes start to dry, and it gets harder to blend new paint into the existing layer.
The result? Rough patches and uneven color.
Choosing the Right Brush for Flat Washes
The good news? The right brush makes a huge difference. They show the brushes they like to use and explain why they work so well for large washes.
Types of Brushes That Work Best
The artist will want to use a big brush that can hold much water and pigment.
- They often reach for their size 12 round sable brush. It’s excellent for covering space while still giving them control.
- Another option is a 1-inch flat synthetic brush. It’s useful when they want clean, straight edges in their washes.
- But their favorite brush for large flat washes is the Haig brush. It’s made from soft natural hair bristles, and it’s super absorbent.
Natural hair brushes soak up more paint and water than synthetic brushes. They stay wet longer, which helps avoid those dreaded dry lines.
Synthetic brushes are more rigid—they snap back quickly and don’t hold as much moisture, making the wash look choppy.
Prepping the Artist’s Paints Before They Begin
Once they’ve got the right brush, the next step is ensuring they have enough paint ready. Make more paint than you think you’ll need—seriously.
The bigger the painting area, the more paint they’ll need. If the palette runs dry halfway through, they’ll have to stop and mix more, which leads to mismatched tones and an uneven wash.
Preparing a full, consistent batch from the start helps maintain the same concentration and color strength from top to bottom.
They’ll save time, avoid stress, and get a smoother result.
Two Techniques for Painting Flat Washes
Once their tools and paints are ready, they can start painting. There are two primary methods they use for flat washes: wet on dry and wet on wet. Let’s break each one down.
#1. Wet-on-Dry Technique
This is the one they use most often. It means applying paint directly onto dry paper.
They always tilt their paper slightly before starting. This helps the paint flow down naturally, forming a bead of water at the bottom of each stroke.
That bead is key. It keeps the edge of the stroke wet so they can continue painting smoothly without hard lines.
They start at the top and overlap each stroke as they move downward, reloading the brush with paint every time to keep the flow even.
When they reach the bottom of the area, they gently blot the excess paint using a paper towel or a dry brush.
If too much moisture is left there, it can backflow and create a bloom—or what’s sometimes called the cauliflower effect.
Once the wash dries, they ensure not to touch it again. That’s important. Any extra strokes can disturb the surface and create unwanted textures.
If they need to darken the area or adjust the value, they wait until everything is completely dry.
Then they paint a second layer, using the same method—top to bottom, with beads at each stroke, and blotting the bottom again.
#2. Wet on Wet Technique
Sometimes, they work in a large area and worry they won’t have enough time for the wet-on-dry method. That’s when they use the wet-on-wet technique.
There’s one thing to watch for: paper buckling. Wet paper tends to form ripples, which makes it harder to create a flat wash.
To avoid this, they use 300 gsm paper that’s 100% cotton and pre-stretch it before painting.
They start by pre-wetting the paper with clean water. But there’s a trick here—you don’t want the paper too wet or dry. They try to make it just evenly damp across the entire area.
Once ready, they load their brush and begin applying the paint. Here, they usually switch to a flat synthetic brush instead of the Haig brush.
Since the paper is already wet, using a super-absorbent brush might flood it with too much water and cause puddles.
You’ll probably notice the paint looks lighter on the paper. That’s because it’s mixing with the water that’s already there.
So, they mix their paint slightly more concentrated to balance that out.
What they like about this method is that it gives them more time. They can go back in and make small adjustments, tilt the paper to guide the paint and blend everything out.
It’s great for scenes with multiple colors, like sunsets, because the transitions look soft and natural.
Comparing Wet on Dry vs. Wet on Wet
Both techniques work, but they give different results.
- Wet on dry gives them more control. They get cleaner edges and more precise colors.
- Wet on wet is more flexible. They get softer blends and a more atmospheric feel.
They use both, depending on the look they’re going for. They recommend trying them both, too. See which one fits your style better.
Closing Words
Flat washes take a bit of practice, but once someone gets the hang of it, they become one of the most powerful techniques in a watercolor toolkit.
Use the right brush, prepare enough paint, and be patient during the drying stage. Why not grab some paints today and give both methods a try?
