Home > Blog > How to Blend Colors in Paint by Numbers
A note before we start
This one is for Laura Shore, one of our most thoughtful and dedicated painters, who emailed us asking whether we had anything on blending. Laura, this blog is for you. Those blocks of colour will not stand a chance.
If you have ever finished a section of your paint by numbers canvas and thought it looked a little flat or blocky compared to what you had imagined, you are not alone and you are not doing anything wrong. The numbered system by design separates colours into individual sections, which produces clean results but can sometimes give the finished painting a graphic, illustrated quality rather than the soft, realistic look of an actual painting.
Blending is how you close that gap. It is not a difficult skill but it does require the right timing and the right approach for each type of surface you are working on. Once you understand the two core techniques and when to use each of them, the difference in your results is immediate and genuinely impressive.
This guide covers both techniques in plain language, tells you exactly which one to use in which situation, and gives you the troubleshooting answers for the most common problems people run into. If your paints are too thick or have dried out before you get to use them, start with our guide on how to revive dried acrylic paint first, then come back here.
What this guide covers
Why blending matters
In the real world, colours rarely sit next to each other with a hard line between them. The blue of a sky fades gradually into the orange of a sunset. Animal fur transitions from one shade to another across dozens of individual hairs. Skin moves through light and shadow in a continuous curve rather than a series of distinct blocks.
Paint by numbers captures these colour transitions by dividing them into numbered sections, which is brilliant for making the process manageable but does produce visible boundaries between colours in the finished piece. Blending is simply the process of softening or removing those boundaries so the painting reads as a continuous image rather than a collection of separate sections placed next to each other.
The good news is that you do not need to blend every boundary in the painting to see a dramatic improvement. Focusing on the transitions that matter most, the sky, the light hitting a face, the gradient in an animal's coat, produces a result that looks significantly more professional with relatively little extra effort.
Technique 1: the dry brush method
This is the technique to reach for when both of the colours you want to blend have already dried. It works by using a clean, dry brush to gently disturb the surface of the dried paint and pull tiny amounts of pigment from each section across the boundary between them, creating a soft and textured transition.
It produces a slightly textured effect rather than a completely smooth gradient, which makes it perfect for surfaces that naturally have texture in real life. Fur, foliage, grass, rough stone, wood grain, and clouds all respond beautifully to this technique and end up looking far more natural than the flat solid sections would suggest.
How to do it
Start by making sure both sections are completely dry. If the paint is even slightly tacky the brush will drag it rather than blend it, and you will end up lifting paint off rather than softening the edge. Five to ten minutes of drying time is usually enough for standard acrylic paint in a warm room, but err on the side of waiting a little longer if you are not sure.
Take a clean, dry brush. It should have absolutely no moisture on it, and no paint. A flat brush with slightly stiffer bristles works better here than a soft round brush because the stiffer bristles create more friction against the canvas surface, which is what actually moves the pigment.
Hold the brush lightly and sweep it back and forth across the boundary where the two colours meet, using a gentle criss-cross motion. You are not pressing down or scrubbing. You are barely touching the surface and letting the bristles do the work. Build the effect slowly with multiple light passes rather than trying to achieve it in one aggressive stroke.
After four or five passes, step back and look at the boundary from normal viewing distance. You will see the hard line beginning to soften into a gradual transition. Continue until you are happy with the result, then leave it alone. Over-working a dry brush blend starts to look chalky.
Technique 2: the wet on wet method
This is the technique that produces the smoothest, most seamless gradients, and it is the one to use for skies, water, skin tones, and any other surface where you want a perfectly soft transition with no visible texture. The principle is simple: you apply both colours while they are still wet and then physically mix them together at the point where they meet.
The challenge with wet on wet is timing. Acrylic paint dries in roughly 10 to 15 minutes depending on room temperature, how thick you applied it, and how humid or dry the air is. You need to work in small sections so you can complete the blending before either colour dries.
How to do it
Choose a small manageable area to start with, perhaps a two-inch stretch of sky where two colours meet. Do not try to blend an entire background in one go until you are comfortable with the timing.
Apply your first colour to its section right up to and slightly past the printed boundary line, using a generous amount of paint. Immediately apply the second colour to the adjacent section in the same way, letting the two wet edges touch each other. Do not wait between applying the first and the second. The whole point is that both are wet at the same time.
Take a third clean brush and dampen it very slightly with water. It should feel barely damp rather than wet. Too much water on the blending brush dilutes the paint and can make the colours go thin and transparent. Draw this clean damp brush gently along the seam where the two wet colours meet, using smooth strokes that follow the direction of the boundary. The wet paint from each side will mix together directly on the canvas, creating a gradient.
The key discipline here is restraint. Make a few strokes and then stop. Every additional stroke you make picks up more of both colours and can start to mix them too thoroughly, turning what should be a gradient into a muddy middle tone. A good wet on wet blend often takes fewer than five strokes of the blending brush.
Which technique to use and when
The choice between dry brush and wet on wet comes down to two questions: have the sections already dried, and what kind of surface are you blending?
| What you are blending | Best technique | Why |
|---|---|---|
| Animal fur or hair | Dry brush | The textured effect mimics the way individual hairs create gradual colour transitions |
| Skies and sunsets | Wet on wet | Smooth seamless gradients look much more natural in atmospheric backgrounds |
| Water and reflections | Wet on wet with horizontal strokes | Water surfaces have a horizontal quality that directional blending reinforces |
| Foliage and grass | Dry brush | Texture adds depth and realism to organic surfaces |
| Skin and portraits | Wet on wet | Skin tones need smooth transitions to look natural rather than contoured |
| Sections already dried | Dry brush only | Wet on wet requires both colours to be wet simultaneously |
Going further: highlights, shadows, and real depth
Once you are comfortable with both blending techniques, the next step is using them to add elements that were not in the original numbered design at all. This is where painting starts to feel genuinely creative rather than just systematic.
Adding highlights
Highlights are the areas where light hits a surface most directly. In a portrait this might be the top of a nose, a cheekbone, or the edge of a lip. In a landscape it might be the crest of a wave or the top of a hill. To add a highlight, mix a tiny amount of white into the lightest colour already present in that area and apply a small amount to where the light would logically land. Then blend the edges softly into the surrounding colour using either method depending on whether the surrounding paint is wet or dry.
Adding shadows
Shadows work the same way in reverse. Mix a small amount of a darker tone or a complementary colour into the darkest colour already present in an area, and apply it to the recessed parts where light would not reach. Blend the edges and the result is a sense of three-dimensional form that the flat numbered system alone cannot produce.
The dry brush texture trick for backgrounds
Once a large background section is completely dry, loading a flat brush with a very small amount of a slightly lighter version of the background colour and dragging it loosely across the surface adds a sense of movement and atmosphere. It is particularly effective in skies, water, and forest backgrounds. This is the same technique professional painters use to make large flat areas feel alive rather than static.
For a complete breakdown of advanced techniques beyond blending, our advanced paint by numbers techniques guide goes deeper into everything from layering to colour mixing.
Fixing the most common blending problems
Ready to practice these techniques on a new kit?
Browse our full range of adult kits or create a custom kit from your own photo. The more detailed designs in our 36 and 48 colour range give you the most opportunity to experiment with blending.
William Murdock, Founder of Paint On Numbers Canada
William started Paint On Numbers after years of testing kits and techniques. He writes these guides because he genuinely believes that better information produces better painters, and better painters enjoy the hobby far more.
Laura, one last thought
The fact that you noticed the blocks of colour and wanted to do something about them means you are already thinking like a painter rather than someone just filling in sections. That instinct is the whole game. Practice the wet on wet technique on your next sky or water section and I think you will be genuinely surprised at what you can produce. Let us know how it goes.