Varnishing an acrylic painting.
Varnishing is a final, key step in producing high-quality work designed to last. If done carefully, varnishing makes a painting easier to clean, protects it from harmful ultraviolet light and adds a sheen that ties the picture together. If you choose to varnish your acrylic painting, pick the right supplies, prepare your surface and apply the varnish to ensure a professional outcome.
Choose Your Supplies
Examples of varnishing brushes.
Varnishes are available as either flexible or rigid, and permanent or removable. Rigid varnishes are not suited for acrylic paintings as they crack when bent, so choose either a permanent or removable flexible varnish. These varnishes are available as gloss (shiny finish) or matte (dull finish). Either finish is suitable for varnishing an acrylic painting.
The brush or pad you use is another consideration. Your brush should be one used solely for varnishing, to avoid transference of paint particles to your finished painting. It should be high-quality, flat and 3/4 to 4 inches wide, with soft, closely packed bristles that won't shed or leave marks in the varnish. Varnishing pads are another option. They create a brushstroke-free surface; just make sure to clean the pad thoroughly to rid the surface of lint, and have a roller pan or foil-lined cookie sheet ready to hold the varnish.
Prepare Your Surface
Before you begin, make sure your painting is completely dry and cured. This means at least three days for a typical acrylic painting. Once dry, make sure your surface is spotlessly clean, as anything you varnish over will become a part of the painting. Set up your painting on a flat surface (never varnish vertically), and make sure you have adequate lighting to see any bubbles or missed spots that may appear as you proceed. You may wish to put something down to protect your surface against drips as well.
Apply the Varnish
Apply the varnish in long, even strokes that go the same direction each time. It is better to apply two or three thin coats and let each dry completely between applications than to do one thick coat. Drying time will vary depending on the type of varnish used, but usually entails two hours or more between coats. While working, watch carefully for bubbles and work them out before they dry. Most importantly, do not reapply varnish to areas that are not completely dry. This may cause cloudiness and mar the surface. If you miss any areas, touch them up once the initial coat has dried completely. When finished, leave the painting to dry flat in a clean area.
