How to Paint a Watercolour Galaxy: A Complete Guide for Beginners

Learning how to paint a watercolour galaxy is one of those things that looks impossibly complicated but is actually surprisingly achievable. There’s something magical about watching deep purples and blues swirl together on your page, then adding stars to create your own little corner of the universe.

I remember the first time I attempted a watercolour galaxy painting. I was convinced I’d mess it up, but the forgiving nature of watercolour combined with the chaotic beauty of space meant that even my mistakes looked intentional. That’s the brilliant thing about painting galaxies—they’re meant to be wild and unpredictable.

If you’re looking for unique subjects to paint that are both impressive and beginner-friendly, watercolour galaxies are perfect. Let me walk you through everything you need to know.

What You’ll Need

Paper

The best watercolour paper makes a massive difference with galaxy paintings. You want something that can handle lots of water without warping or pilling. Look for 100% cotton, cold-pressed paper at 300gsm minimum. Good quality paper lets you layer colours without the surface breaking down.

I know better paper costs more, but trust me on this one. Cheap paper will frustrate you. The paint sits on top rather than soaking in properly, and you’ll struggle to get those smooth transitions that make galaxies look dreamy.

In these pictures, I’m using Arches 100% cotton cold-pressed paper.

Paints

For watercolour paints, you’ll want rich, saturated colours. Tubes of watercolour paint give you more intense pigments than pans, which is helpful for getting those deep space colours. That said, pans work fine if that’s what you’ve got.

Essential colours for galaxies:

• Prussian blue or dark blue
• Ultramarine or cobalt blue
• Permanent rose or magenta
• Purple or violet
• Black paint (though you can mix a dark from blue and brown)
• Light blues like cerulean
• White gouache

Watercolour white is pretty useless for stars. You want white acrylic paint or gouache for the bright spots. More on that later.

Brushes

A round brush is your main tool. I use a size 6 or 8 for most of the painting. You might also want a flat brush for laying down large washes, but it’s not essential. Make sure your watercolour brushes hold water well and come to a decent point.

Other Supplies

Here’s what else you’ll need:

• Two jars of clean water (one for rinsing, one for keeping your water clean)
• Paper towel for blotting and lifting colour
• Masking tape or washi tape to secure your paper
• White gel pen for tiny stars
• An old toothbrush for splattering (optional but fun)
• Table salt for creating texture (optional)
• A palette for mixing

Understanding the Right Techniques

Before we dive into painting, let’s talk about the specific technique that makes galaxy paintings work.

The Wet-on-Wet Technique

This is your best friend for galaxies. The wet-on-wet technique involves applying wet paint to wet paper, which creates those gorgeous soft bleeds and colour transitions. It’s what gives galaxies that dreamy, nebula-like quality.

The trick is controlling how much water you use. Too much water and everything becomes a muddy puddle. Too little and you won’t get proper blending. Your paper should have a sheen but shouldn’t have visible puddles sitting on top.

Wet Graduated Wash

A wet graduated wash is when you transition smoothly from one colour to another. This technique is brilliant for creating depth in your galaxy. You might go from dark blue at the edges to light blues in the centre, suggesting distance and light sources.

Dry Brush Technique

The dry brush technique is useful for adding texture later. With a damp brush (not wet, just damp), you can drag colour across the paper to create wispy clouds or add definition to your galaxy’s edges. It creates hard edges rather than soft ones, which adds variety to your painting.

How to Paint a Beautiful Watercolour Galaxy: Step by Step

Right, let’s get painting. This is the easy way to create your first galaxy.

Step 1: Prepare Your Paper

Tape down your paper with masking tape or washi tape. This keeps it flat as you work and gives you nice, clean edges when you’re done. Make sure the tape is secure, especially if you’re using lots of water.

Step 2: Wet Your Paper

Using clear water and a clean brush, wet the entire area where you want your galaxy. You want the paper evenly damp but not swimming. This is crucial for getting smooth transitions between colours.

Step 3: Drop in Your First Colours

While the paper is still wet, drop in your darker colours. I usually start with dark blue around the outer edges. Don’t worry about being neat. Let the paint spread naturally.

Add your next brush stroke with purple or magenta. Watch how the colours blend on the wet paper. You can tilt your board to encourage the paint to flow in certain directions.

The best general tip I can give you? Don’t overthink it. Space is chaotic. Let the watercolour do its thing.

Step 4: Build Up Layers of Colour

Let your first layer dry completely. You can use a hairdryer if you’re impatient (I always am), but make sure it’s genuinely dry before adding second layers.

Now wet selected areas again and add more colour where you want deeper, richer tones. This is where you create dimension. Add the darkest colour in patches to suggest depth and swirling cosmic dust.

Between layers, you might use a paper towel to lift out lighter areas where you want bright nebula clouds or light sources. Blot gently while the paint is still damp.

Step 5: Add Light Layers

Mix lighter versions of your colours (add more water) and paint light layers in some areas. This creates contrast and makes your galaxy feel three-dimensional. A lighter area in the centre can suggest a bright cluster of stars or a distant nebula.

Good colour combinations for this stage include light blues mixed with tiny touches of purple, or pale pink with hints of blue. Keep these washes transparent so your darker colours show through.

Step 6: Create Texture (Optional)

While your paint is still wet, you can sprinkle salt over certain areas. The salt absorbs the water and creates a crystalline, starry texture. Let it dry completely, then brush off the salt grains. It’s a good way to add visual interest without much effort.

Step 7: Add Stars

This is the fun bit. Once everything is bone dry, it’s time for stars. You’ve got several options:

White Acrylic Paint or Gouache: This is my favourite method. Thin your white acrylic paint slightly with water (but not too much—you want it opaque). Load an old toothbrush, then run your finger along the bristles to splatter tiny dots across your galaxy. You can also use another paintbrush to tap your loaded paintbrush with. Cover areas you don’t want spattered.

White Gel Pen: A white gel pen is perfect for adding deliberate stars of various sizes. Draw bigger stars in the foreground and tiny dots in the background. You can even add little cross marks to make stars look like they’re twinkling.

White Pen: Similar to the gel pen, but sometimes gives a cleaner, brighter white. Great for larger, more prominent stars.

Vary your star sizes and density. Real galaxies have clusters of stars and empty patches. Don’t cover every centimetre evenly.

Advanced Techniques for Watercolour Galaxies

Creating Depth with Multiple Layers

The difference between an okay galaxy and a stunning one often comes down to layering. Professional-looking watercolour galaxies usually have three to five layers of colour.

Start with your lightest washes, then build up to your darkest areas. Each layer adds depth and complexity. The trick is letting each layer dry completely before adding the next. Rushing this creates muddy colours instead of rich, deep tones.

Mastering Smooth Transitions

Smooth transitions are what make galaxies look professional. The key is working quickly while your paper is wet. If the paper starts drying, you’ll get hard edges and visible brush strokes.

Mix your colours on your palette before applying them, so you’re not faffing about while your paper dries. Have your next colour ready to go before you need it.

Working with Water

Controlling water is the trickiest part of watercolour painting. For galaxies, you want quite a bit of water for the initial washes, but not so much that you lose control entirely.

If you’ve added too much water, blot with a paper towel. If an area is too dry and not blending, add a lil water with a damp brush to reactivate the paint. Keep your water clean between colour changes, or you’ll end up with murky tones.

Creating Nebula Clouds

Nebulas are those gorgeous, cloudy areas in galaxies. To create them, drop concentrated colour into wet areas, then immediately soften the outer edges with clear water on a clean brush. This creates soft, cloud-like forms with intense colour in the centre, fading to nothing at the edges.

Common Mistakes (And How to Fix Them)

Using too much water is the classic error. Your galaxy will look washed out and pale. If this happens, let it dry completely, then add more concentrated colour in layers to build up depth.

Not letting layers dry creates mud. Patience is annoying but necessary. Genuinely wait until each layer is dry.

Making all your colours the same value is another common issue. You need dark darks and light lights. Don’t be afraid to go really deep with your darkest colour—that’s what makes the bright bits pop.

Overworking the paint destroys that fresh watercolour quality. Once you’ve dropped your colours in, leave them alone. Let the water do the work.

Different Styles and Approaches

There’s no single right way to paint galaxies. Some people prefer realistic approaches, following tutorials from astrophotography. Others go completely abstract and whimsical.

You might paint a swirling spiral galaxy, or a nebula cloud, or a simple starry sky. Each requires slightly different approaches but uses the same basic techniques.

Try painting galaxies in unusual colour combinations—greens and oranges, or yellows and purples. Real space contains all sorts of colours we don’t typically associate with galaxies.

YouTube Tutorials Worth Watching

Sometimes following tutorials helps things click. Here are some brilliant channels for galaxy painting:

• The Mind of Watercolour Has several galaxy tutorials with clear explanations
• Makoccino – Gorgeous, whimsical galaxy paintings
• Kelogsloops – Beautiful galaxy backgrounds in portrait paintings
• Sarah Cray – Simple, beginner-friendly galaxy techniques
• Jessica Sanders Art – Detailed galaxy tutorials with lots of tips

Search for “watercolour galaxy tutorial” on YouTube and you’ll find loads more. I like watching a few different artists to see various approaches before developing my own style.

Creative Projects with Galaxy Paintings

Once you’ve practised a bit, you might want to incorporate your galaxies into other projects:

• Paint galaxy backgrounds for constellation art
• Create galaxy bookmarks
• Make greeting cards with galaxy designs
• Paint small galaxy studies in a sketchbook
• Combine galaxies with silhouettes of trees, mountains, or animals
• Paint moon phases with galaxy backgrounds

Galaxy paintings also work beautifully with other forms of watercolour art. You could paint a galaxy inside a geometric shape, or use galaxy techniques to create abstract pieces.

Tips for Better Results

Work from light to dark. It’s much easier to darken areas than to lighten them with watercolour.

Use reference images from NASA or astronomy websites. Even if you’re going abstract, looking at real galaxies helps you understand how colours and light work in space.

Don’t make your black paint too dark initially. Build up to true black gradually, or you’ll lose the ability to add depth later.

Vary your star placement. Cluster them in some areas and leave others relatively empty. Real galaxies aren’t evenly distributed.

Consider the light source. Even in abstract galaxies, having a sense of where light is coming from makes the painting more believable.

Troubleshooting Common Issues

My colours look muddy: This usually means you’ve mixed too many colours together or worked the paint while it was semi-dry. Either let each layer dry completely before adding the next, or work entirely wet-on-wet. The in-between stage creates mud.

My white paint isn’t showing up: Watercolour white is transparent. For stars, you genuinely need acrylic, gouache, or a white pen. It’s one of the few times watercolour painters need to use opaque paint.

I’ve got hard edges everywhere: This means your paper dried before you finished blending. Work faster, or rewet areas as you go. You can also soften hard edges by running a damp brush along them while they’re still slightly wet.

My galaxy looks flat: Add more variation in your values. You need really dark darks and preserved light lights. More layers help too.

The paint has gone under the masking tape: If you take your masking tape off and some of the paint has bled, just paint over with white gouache.

Keep Experimenting

The beautiful thing about learning how to paint a watercolour galaxy is that each one turns out differently. The unpredictable nature of watercolour combined with the chaotic beauty of space means you’re constantly discovering new effects.

If you’re new to watercolour entirely, you might want to check out my guide on how to start watercolour painting, which covers fundamental techniques you’ll use for galaxies and everything else.

Don’t be discouraged if your first galaxy doesn’t look like a NASA photograph. Even “failed” galaxy paintings usually look interesting. The key is to keep painting them. Each one teaches you something about water control, colour mixing, and timing.

Space is vast and weird and wonderful. Your galaxy paintings can be too. So grab your paints, stop overthinking it, and create your own little universe.

I’d love to see what you create, so feel free to share your watercolour galaxies with me on social media. Happy painting!

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