How long should an acrylic painting dry before varnish is applied?

Reader Question: How long should an acrylic painting dry before varnish is applied?

Although acrylics dry quickly on the surface, you should wait at least a week before varnishing to make sure that the acrylics have dried through all the way. Even if an acrylic painting is dry to the touch hours after painting, it is often still a bit wet underneath. If you varnish your painting too soon, before the acrylic paint has dried all the way through, the varnish may wind up cloudy due to the trapped moisture.

I suggest a minimum wait time of one week, but some acrylic artists wait as much as 6 weeks, just to be sure the acrylic paint is fully dried through and through. Let these timeframes serve as general guidelines, because the actual length of time it will take for your acrylic painting to dry depends on several factors, such as:

  • How you applied the paint - thinly, thickly, with or without added mediums or gels?
    If the paint was applied in a thick impasto style, it will take longer to dry than if you painted in thin washes. Likewise, adding gels or mediums to the acrylic paint will also effect the drying time - either speeding it up or slowing it down.
  • Temperature and humidity - the temperature and humidity of both the area where the painting was created and the area where it is drying will affect the drying time of the paint. It is best to both paint and store your paintings in an area with constant room temperature and low humidity.
  • Ventilation - the flow of air (or lack of it) will affect the paint's drying time. A normal air flow will help along the drying process, whereas stagnant air will slow it down and maybe even cause a milky film to develop on the paint.

If you're interested in learning more about the drying properties of acrylics, Golden has put together these Technical Notes on Drying which are quite informative.

In general, use your best judgment to determine whether your acrylic painting is ready to be varnished, based on the factors listed above.

Hope that helps!

Check out my guide to Painting with Acrylics