Forever Art: The Ultimate Guide to Sealing & Varnishing Paint by Numbers
Article Summary
Finishing the painting is only half the battle. To keep your artwork vibrant for decades, you need to seal it. This guide covers the "why" and "how" of varnishing, compares different finishes (Matte vs. Gloss), and warns against common mistakes that can ruin your canvas.
You’ve done it. You spent weeks carefully filling in every numbered section of your Famous Artist Recreation. It looks perfect. But right now, that acrylic paint is vulnerable.
Acrylic paint is durable, but it is porous. Over time, it collects dust, dirt, and oils from the air. Even worse, UV light from your windows can cause those vibrant colours to fade. This is why museums seal their art, and why you should too.
Why Varnish? (It's Not Just About Shine)
Many beginners skip this step, thinking it is unnecessary. Here is why professional artists consider it mandatory:
- UV Protection: High-quality varnish acts like sunscreen for your painting, blocking harmful rays that fade pigment.
- Dust Resistance: Varnish creates a non-porous seal. If your painting gets dusty, you can wipe it clean with a damp cloth without damaging the paint.
- Colour Saturation: Acrylics often dry "flat." A coat of varnish re-saturates the colours, making blacks deeper and brights more vibrant.
⚠️ The Hairspray Myth
Please do not use hairspray to seal your painting.
We see this advice on social media constantly. Hairspray is not archival. It contains acids that will yellow your painting over time and make the surface sticky, attracting more dust. Always use a proper acrylic polymer varnish.
Choosing Your Finish: Matte, Satin, or Gloss?
Varnish comes in three main sheens. The choice is aesthetic; there is no "wrong" answer, but it changes the mood of the piece.
The finish you choose dramatically changes how light interacts with your art.
- Gloss: Highly reflective. It makes colours "pop" the most, but can cause glare if the painting is near a window.
- Matte: No shine. It keeps the colours true to how they look when dry. Great for a modern, understated look.
- Satin: The middle ground. It has a soft, pearl-like sheen. This is the most popular choice for Paint by Numbers.
Step-by-Step: How to Apply Varnish
You don't need expensive equipment. You just need a bottle of acrylic varnish and a wide, soft, flat brush. We recommend standard professional brands like Liquitex or Winsor & Newton, which are widely available.
Step 1: The Waiting Game
Wait at least 1 week after you finish painting. Even if the paint feels dry to the touch, acrylics need time to fully "cure" and settle. Sealing too early can trap moisture.
Step 2: Clean the Surface
Use a lint-free cloth or a soft brush to gently wipe away any dust or pet hair from the canvas. You don't want to seal a hair into your masterpiece forever!
Step 3: Apply in Thin Layers
Lay your canvas flat on a table covered with newspaper.
Pour a small amount of varnish onto the canvas or into a shallow dish. Dip your brush and apply it in long, even strokes, going from top to bottom. Do not overwork the brush back and forth, as this creates bubbles.
Apply long, smooth strokes to avoid brush marks.
Pro Tip: It is better to do two thin coats than one thick coat. Let the first coat dry for 3-4 hours before applying the second coat perpendicular (side-to-side) to the first. This ensures 100% coverage.
What Comes Next?
Once your varnish is dry (usually 24 hours), your painting is fully protected. The colours will look richer, and the surface will be tough enough to handle.
The final step? Getting it on the wall. If you haven't framed your canvas yet, check out our guide on How to Frame Your Paint by Numbers the Easy Way.
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