HOW TO VARNISH YOUR ACRYLIC PAINTINGS
by Joelle Steele
A painting is never complete until you have varnished it. Varnishing is the final step in the process of creating a work of art. It will provide a nice even finish to the painting so that it is all equally matte or glossy in appearance. But, varnish does more than improve or enhance the appearance; it is also how you protect your painting from future damage by dust and dirt, and even some forms of environmental pollution. In other words, it's a necessary process for every artist.
TYPES OF VARNISH
Permanent or Removable. Varnishes for acrylic (polymer) paints come as water-soluble or solvent-based. Whichever you choose, it is preferable to find one that can be easily removed and reapplied should it become discolored over time. Don't make the mistake of using a gel medium as a varnish, because if it has to be removed for cleaning, the painting may be damaged in the process.
Liquid or Spray. Spray seems like it would be the easiest, but it really isn't. The point is to get the varnish applied evenly, and for that, a liquid varnish brushed on is best.
Matte/Satin or Gloss. There are pros and cons to each. Matte or satin finishes can leave a painting looking slightly cloudy and can also dull the details. Gloss varnishes are completely clear and come in gloss and semi-gloss. They make most art look very beautiful and they help bring out the finer details.
Diluting Varnish. Some people like to dilute their water-soluble varnishes with water. Follow the manufacturer's advice on this. I only work with straight varnish and do not dilute it, as I feel the undiluted varnish gives superior results.
WHEN TO VARNISH
Apply varnish only after the painting is completely dry. This is especially important if you paint in a heavy impasto style. You want the thick layers of paint to dry thoroughly. Even if you don't apply paint very thickly, you should still wait at least three days to a week or more before you apply the varnish.
WHERE TO VARNISH
Varnishing requires excellent lighting. You need to be able to see exactly where you are in the process — what parts of the canvas are shiny and which are less shiny (still in need of varnish). A bright overhead light is helpful if you don't have a sunny window in your workspace.
TOOLS FOR VARNISHING
Use a 2" or so soft flat brush for varnishing. Be sure it is a good quality brush that won't lose any bristles along the way. Use a small, heavyweight bowl (so that it won't tip over if you bump it) that can accommodate the width of your brush. You can lay the painting flat or prop it up on an easel, although varnishing on a flat surface is less likely to result in drippage.
HOW TO VARNISH
Begin by pouring some varnish into your bowl. Only pour as much varnish as you can apply in about a 3- to 5-minute period. You can always pour more into the bowl as you go.
With small canvases (24" x 32" or less), you can pretty much brush across the entire short width of the canvas. With bigger canvases, you might want to varnish by area (the sky, the red section, the trees, in quadrants, etc.), depending on the individual painting.
The direction in which you varnish should follow the strokes of the paint. If there are no visible strokes and only very thin layers of paint, apply the varnish so that it follows the lines of the art, or else you may end up with noticeable brush lines going in different directions. If you paint impasto, even the slightest textured areas of it, you will need to apply the varnish into the recessed spaces. Do not scrub when you do this, but make sure you don't leave any milky areas of varnish anywhere. Some artists varnish in alternating directions with each coat. I do my skies with horizontal strokes and do the rest according to what each area looks like.
Periodically tilt your canvas into the light to see how well you are covering it. This is a little harder when you're on the second coat, but if you look very carefully, you will soon get used to seeing what the moist coat looks like in comparison to the dried coat, even when you're working with high gloss varnishes.
HOW MANY COATS
Two to three coats of varnish is usually a necessity. Make sure that the painting dries out thoroughly between coats. Generally, three to six hours between coats is adequate when the room is toasty warm. Once the final coat is dry, hang the painting to dry out even longer — at least a week or two — before you store it or show it.
There are very few problems with varnishing aside from the fact that it is a rather boring task that has to be done. If you see that the varnish in your bowl is picking up color from the painting, stop what you're doing immediately. You have either varnished before your painting was thoroughly dry, are using a brush that is far too stiff, or you are scrubbing as you apply the varnish.
Your art will ultimately be someone's investment, and you need to be sure that investment is protected. Using the right varnish and applying it correctly, will ensure that your art is attractive and safe for a lifetime or longer.
This article last updated: 10/25/2014.