Varnishing a Painting
There are many reasons to varnish your acrylic painting, although some artist are adamant that acrylic paintings should not be varnished.
Varnish protects your painting from dirt, dust, UV rays and yellowing. Varnish also unifies uneven tones caused by using various mediums and water on different areas throughout your painting.
Varnishes are typically made from solvent and resin. A good gloss varnish can enhance the vibrancy of the colors in a painting, especially dark colors giving it the look of an oil painting.
A matte varnish can soften the colors in a painting. It is not a good idea to use a matte varnish on a black background as it can leave a milky appearance to the paint.
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Types of Varnish
Varnish comes in gloss, matte and satin varieties and can be either permanent or removable.
There are many different brands on the market. Each brand has their own method of application so read the directions before proceeding.
The different types of varnishes can be mixed together or applied one on top of the other to get the effect you want in your painting.
Matte varnish can, in some cases, make the paint appear slightly lighter. Gloss varnish can enhance the depth of color, especially dark colors, making them “pop”.
Varnish comes in jars or spray cans. There are pros and cons to each one.
I personally like to give the painting a light mist of spray varnish and then go over it with a brush application of a couple of coats of gloss varnish.
I find it easier to avoid brush strokes and bubbles this way.
There is also less chance of some paint coming off and mixing with the varnish. This can happen if you have used a lot of water to thin down your paint.
Varnish will typically appear cloudy or milky when you apply it, but it will dry clear.
Before You Varnish Your Acrylic Painting
Before you varnish an acrylic painting, make absolutely sure that your painting is dry. For oils this could take months. For acrylics it usually takes a day or two.
I like to wait at least a week, especially if its humid (which rarely happens here in the frozen north).
If you have done a heavy impasto type painting you may want to wait a coupe of weeks to make sure all of the layers are dry.
Also, before you varnish sign your work and take photos or scans. Varnish, even matte varnish, will cause a glare that can be hard to work around to get a great photo.
Isolation Coat (Optional)
An isolation coat is a permanent coat of varnish applied to your finished painting before the top varnish coats. It is an optional step that not all artists see as necessary.
There are a couple of reasons you may want to apply an isolation coat.
1. If you think the top layer of varnish may need to be removed at some later date due to damage or for cleaning purpose, the isolation layer will protect your work.
Varnish is typically removed with ammonia and should only be done by someone who is experienced in this type of work.
2. Using a matte varnish on a bare painting can sometimes make the painting appear cloudy.
This happens because the varnish agent can be absorbed into the painting leaving the matte agent, which is typically white, sitting on the surface.
An isolation coat will prevent this absorption.
You can apply one or two coats of varnish for your isolation layer and leave it to dry for 24 hours before continuing with your top coats of varnish.
Golden Soft Gel (Gloss) is the best type to use for this process. It is usually mixed 2-1 with water. Read the instructions for best results.
Make sure your work is clean and dust free and use distilled water for mixing to ensure no dust or tiny specks get embedded in your finish.
To varnish your acrylic painting you will need a large, flat brush that isn’t too stiff. I find old, worn out brushes work best.
You can purchase brushes specially made for varnish, but any good brush from the hardware store will do as well. Snip the ends of the brush slightly to give it that worn feel and prevent brush strokes.
Make sure the bristles don’t come out easily and get stuck in your varnish. Keep this brush strictly for varnishing to prevent contamination with paint.
You will also need a jar for mixing varnish, some paper towels or paint rags, something to protect the surface under your painting (I usually use cheap garbage bags from the dollar store), distilled water and a stick or palette knife to stir the varnish.
Steps to Varnish an Acrylic Painting with a Brush
1. Start by deciding if you are going to use a spray or brush. For flat, smooth surfaces a brush is fine.
For impasto or textured surfaces sprays work better because a brush can leave little pools of varnish in cracks and crevices.
2. Wipe off your painting and check to make sure there is no dust or dirt on it.
3. Protect your surface with garbage bags or drop cloths.
4. Lay your painting on a flat surface. Placing it upright on an easel can cause runs in the varnish.
If you are varnishing a canvas board or will be varnishing the sides of your canvas, put something under it to raise it slightly off your surface.
I use four dominoes on smaller works and a large tub of gesso or two with a board propped on top for larger pieces.
5. Read instructions on container!
6. Pour your varnish into a dish large enough to accommodate your brush, which should be two inches or larger.
I found the best thing to use for this is old glass or ceramic serving dishes I have picked up at yard sales. ( I love to recycle. ?) They are usually big enough and easily cleaned.
7. If you are doing an isolation coat first, mix the varnish with water according to the manufactures instructions. Stir gently!
Vigorous stirring or shaking can cause bubbles and foam to form.
8. Dip your clean brush into the varnish about ¼ to 1/3 of the way up the bristles. It is best to use a brush that has only every been used for varnish.
The chemicals in the varnish can loosen dried paint and cause specks and discoloration in your varnish.
9. Starting in the center, move from one side to the other on your canvas with long, even strokes. Don’t go back over partially dry varnish as it will cause a cloudy appearance in your work.
Get eye level with your painting from time to time to check for areas you missed. Apply horizontally for the first coat and vertically for the second to ensure you haven’t missed any areas.
( A second coat is optional but I prefer multiple thin coats).
10. Let your painting dry for 4 to 6 hours before disturbing it. It may be dry to the touch before this but I am always overly cautious.
Set it in an out of the way place for a couple of weeks to let it cure completely.
Spray Varnish For Acrylic Paintings
1. Follow steps 1 to 5 above.
2. Shake the can of varnish vigorously. This step is important to make sure all of the chemicals have been mixed and you get a satisfactory finish.
Shake again every few minutes while you are spraying.
3. Spray a little on an old piece of canvas or a board to make sure the varnish is flowing properly and the nozzle isn’t spitting.
Keep a rag handy to wipe the nozzle and spray on the scrap canvas during the varnishing process.
4. Hold the can away from your painting at a distance recommended by the manufacturer (did you read the instructions?).
It is usually around 30 cm (about 12 inches). Holding the spray can too close will give you “hot spots” on your painting where there is more spray concentrated in one area.
5. Begin spraying off the edge of your canvas and spray past the other end so you don’t have obvious stop and start lines.
Spray evenly and lightly. 2 to 3 coats should be enough to protect your paining, but you can do as many as you want depending on the effect you are going for.
6. Clean your spray nozzle well so that it won’t be clogged when you want to varnish another painting.
7. Spray varnish dries pretty quickly, but I still like to let mine cure for a week or two just to be sure.
This is a good video from Liquitex explaining the difference in varnishes.
If you are varnishing an acrylic painting for the first time, practicing on a practice canvas might be a good idea.
You can get used to the distance for spraying and the pressure needed for getting a smooth finish with a brush. You can also see which type of varnish you prefer, matte, satin or gloss.
Thanks for reading.