how soon can you varnish an acrylic painting
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.