How to stop dust settling in the varnish

Reader Question: I have an acrylic painting that is mainly white and the second I start applying the varnish, I watch and it seems that any speck of dust in the air makes a beeline for the varnish.

These are tiny little hairs about 2mm long and tiny specs of dust. Trying to pick them out is barely an option because there are so many of them that by the time I'm halfway through, the varnish has become tacky and the dust is difficult to remove. I thought it was due to the brush, but I've washed this thoroughly. Any ideas? Has the varnish got some sort of static property?

Also, how come the same doesn't happen when I apply the acrylic paint itself? I am using water based matte acrylic varnish. Any help would be much appreciated as it's putting me off painting anything else when the result is being ruined.  

Varnish does seem like a magnet for dust! I haven't had problems as extreme as yours, but I know what a pain it can be to try to pick out dust and tiny hairs from varnish - especially over white parts of a painting.

Here are some ideas that might help reduce the amount of dust that falls into your varnish:

Please note: If you try out any of these varnishing suggestions, test them out first on paintings you don't really care about to see how well the various methods work. If you are pleased with the results, then try it on your "real" paintings..

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  • Use thinner layers of varnish so that it dries faster, giving dust less of a chance of falling on your artwork.
  • Consider using a spray varnish, which you can apply while the painting is upright, leaning against a wall or easel, instead of flat.
  • Similarly, if you prefer to brush on your varnish, you could try varnishing your painting vertically by leaning it at an angle against your wall or easel. Brushing on varnish this way is usually not recommended, because the varnish may drip down unevenly and form a puddle at the bottom - but the benefit of varnishing vertically is that it will also make it harder for dust to settle onto the varnish. Therefore you should do thinner layers of varnish than you would normally do, to prevent the varnish from running and puddling.
  • Varnish your paintings in a room that is easier to make dust-free. This would be a room with tile, wood, or linoleum flooring. A room with minimal furniture and clutter is ideal, because dust will have had less chance to settle. It is also best to use a room where animals don't have access.
  • Make sure your a/c vents are cleaned and replaced regularly. You could also consider getting an air filter or purifier.

  • Before you varnish your painting, make sure that the surface of the painting is free from dust. There are a few ways you can do this:

    ...Use an air compressor to blow away the dust.

    ...Run a soft, clean brush across the surface of the painting to kick up any existing dust, and use a vacuum hose to suck the airborne dust away.

    ...Carefully wipe the surface of the painting with an electrostatic cloth (like a Swiffer Dry Cloth), or a microfiber cloth.

    * It is recommended that you test these methods of removing dust from the surface of your paintings on a "scrap" painting first, to reduce the chance of any unpleasant surprises when you prepare a "real" painting for varnishing.

  • The night before you plan to varnish your painting, vacuum the room with a HEPA vacuum cleaner. HEPA stands for High Efficiency Particulate Air and refers to a special filter inside the vacuum that can trap small particles like dust. Vacuum the floor and also the tops of tables, bookshelves, and lamps. You can even run the vacuum over the walls with a special attachment.

    Allow any remaining dust to resettle overnight, and then varnish your painting.

  • Before you varnish, spray or sprinkle a bit of water on the floor. This will help keep the floor dust on the floor.
  • Use a mister to spray water around the room to create a more humid environment. Dry air can attract dust through static electricity. You could also use a humidifier to introduce more moisture into the air. Some people even varnish their paintings in the bathroom after running a hot shower to make the air steamy and moist!
  • Turn off the a/c or any fans, because the circulation of air can kick up dust.
  • Rig up a protective area to keep your painting while the varnish is drying. For example, you could place an even stack of books on each side of the painting, then place a piece of sturdy plexiglass or sheet of wood over top, allowing a small amount of space between the plexi/wood and the surface of your painting. Air will still be able to flow through the protective area, but dust won't be able to land on top of your painting.
  • Some artists have been able to overcome the dust-in-varnish problem by first applying an isolation coat (which acts as a barrier) and then applying the varnish. You can read about Golden's recommended procedure for applying an isolation coat, followed by varnish, here.

As for whether varnish has some sort of static property, I wasn't able to find an answer on this. Golden Paints has conducted experiments to determine whether acrylic paints carry a static charge, but their results (happily) indicated that acrylics paints do not carry one.

I'm guessing that dust is more attracted to varnish and acrylic paints for two reasons:

  • Acrylic paint doesn't stay wet as long as the varnish, so dust has more of an opportunity when it comes to varnish, and
  • Most varnishing is done with the painting lying flat, while the actual painting is created upright on a wall or easel.

There could very well be other, more scientific reasons that explain why varnish attracts dust more easily than paint, so if someone knows, please enlighten us!

I hope that helps! Wishing you the best of luck with it!