Varnishing an Acrylic Painting: A Step-by-Step Guide

Varnish an acrylic painting once it is completely dry: remove the dust, apply the varnish in thin, even coats and let it dry in a dust-free room. Varnish protects the paint from dirt, moisture and UV light and gives the painting a uniform surface – gloss, satin or matte. Patience and thin coats are what matter most.

In this article I explain why varnishing is worthwhile, how long to wait first, which varnish suits your painting and which mistakes to avoid.

Why varnish an acrylic painting?

Dry acrylic paint is water-resistant, but its surface stays slightly tacky and attracts dust. Over the years, dirt settles into the paint layer and becomes almost impossible to remove. A varnish forms a protective layer on top that can be cleaned carefully if needed.

Varnish also evens out differences in sheen. Many acrylic paintings have matte and glossy areas side by side, depending on how thickly or thinly the paint was applied. After varnishing the surface looks uniform, and dark colours often regain their depth. Many varnishes also contain UV protection, which slows the fading of sensitive pigments.

When is an acrylic painting dry enough?

Acrylic is touch-dry quickly, but may still hold moisture underneath. Varnishing too early traps it and can make the varnish cloudy.

• Thinly painted works: wait at least a few days.
• Impasto and palette knife work: thick layers need much longer – one to two weeks is sensible.
• Texture pastes or collage materials: give it even more time.

Always follow the instructions on your varnish as well.

Gloss, satin or matte?

• Gloss: colours look rich and deep, but the surface reflects more.
• Satin: a good compromise for most paintings – lively colours, little glare.
• Matte: calm and reflection-free, though dark colours may look slightly lighter.

You can also combine them, for example a gloss coat for depth followed by a satin coat. Test the varnish on a sample first.

Spray or brush-on varnish?

Spray varnish

Easy to use and free of brush marks – ideal for heavily textured paintings. Spray in a well-ventilated room or outdoors without wind and keep the recommended distance.

Brush-on varnish

Easier to control and forms a slightly stronger layer. Apply it with a wide, soft flat brush, working quickly in one direction.

Varnishing step by step

1. Check the painting: press gently at the thickest spot – it must not give or feel sticky.
2. Remove dust with a soft dry brush or a lint-free cloth.
3. Lay the painting flat so the varnish does not run.
4. First thin coat: apply evenly from one side to the other without going back over wet areas.
5. Let it dry somewhere dust-free – an upturned box over the painting helps.
6. Second coat at right angles to the first.

Common mistakes

• Varnishing too early: trapped moisture clouds the varnish.
• Coats too thick: runs, drips or a milky finish.
• Dust and hairs: they stay sealed in forever.
• Bubbles from shaking: stir brush-on varnish gently instead.
• Cold, damp rooms: slow drying and possible clouding.

Frequently asked questions

Does every acrylic painting need varnish?

No, but it is recommended if the painting should last or will be sold. Practice pieces don't need it.

Can I use clear lacquer from the hardware store?

I advise against it – such lacquers are not made for artists' paints and may yellow. Use a varnish for acrylic painting from an art shop.

Can I keep painting after varnishing?

Acrylic often adheres poorly to varnish, so only varnish once the painting is truly finished.

Is a painting from a course already varnished?

No – a fresh painting must dry first. You take it home and can varnish it later at your leisure.

Conclusion: a good finish for your painting

Varnishing an acrylic painting is not difficult: wait until the paint is fully dry, remove dust and apply two thin coats. That keeps your painting vivid and protected for years.

Want to paint an acrylic picture worth varnishing first? In my painting courses and workshops you create your own painting in one session, for example in the course Stille Nacht. How to prepare is explained in preparing for a painting course.