So, you’re thinking about varnishing your oil painting. But where do you even begin? And should you even do it?
If you’re trying to decide which varnish is best for you, how to apply it, and how long the process takes, then you’ve come to the right place.
In this post, you’ll find answers to all of these questions. Plus, find out how the great artists of the past preserved their beautiful pieces before modern varnishes came into the picture.
What Does Varnish Do?
Varnish is a coating that can be applied to a painting’s surface in liquid or spray form. It protects the paint layers by keeping them dirt, smoke, and dust free.
You can think of varnish like a pair of gardening gloves. If your hands (or painting) aren’t protected, eventually, they’ll become covered in dirt, scratched up, and a little sunburnt.
Sure, you’ll be able to wash the grime off, but you could’ve avoided the mess altogether and protected your skin just by wearing gloves.
The same is true of varnish. Just a thin layer protects your precious painting from damaging UV rays and nasty contaminants that float around, wreaking havoc over time.
Do You Have to Varnish Oil Paintings?
No, you don’t have to varnish your oil paintings, but many art conservators highly recommend it.
Varnishing oil paintings is an optional step that adds a layer of protection and also changes the appearance. Depending on the look you’re aiming for, the right varnish can make your painting appear matt and ‘flatten’ the colors or give it a glossy finish that boosts the painting’s saturation.
When Were Varnishes First Used?
The first varnishes were used in the 16th century and were made from resin. They were “hard natural varnishes” like Copal and Amber. Over time, these resins tend to crack and turn yellow or brown, which leads to long hours of tedious work for modern day conservators.
Take a look at how yellow this poor lady was before the original painting surface was revealed.
Mediums You Can Varnish
Watercolor, oil, and acrylic paintings can all be varnished but require slightly different processes.
Oil paintings can be varnished directly since the protective layer doesn’t compromise the paint.
Plus, there may come a time when you (or someone centuries from now) want to remove the varnish and apply a fresh coat. For other mediums, stripping the varnish off of the paint would ruin the piece. However, oil paint isn’t harmed during the process; we’ll go into that later.
Read up on the best varnish for oil paintings.
On the other hand, an acrylic painting requires an isolation coat before varnishing. Otherwise, it can absorb into the paint surface and damage your piece. Once a permanent isolation coat is applied, then you can paint over the top with varnish. If you ever want to remove the varnish, the isolation coat protects the painting forever from the solvents used to strip the varnish away.
Though most artists fear varnishing their watercolor paintings, it can be done.
But before you even think about brushing on a layer of varnish, you have to spray your piece with a few thin layers of fixative. This will create a barrier between the actual pigments and the varnish. Without it, your watercolor piece can be destroyed.
Once the fixative is dry, you can either apply varnish directly, or an isolation coat followed by varnish, depending on your preference.
How Long to Wait Before Varnishing
Depending on the medium and thickness of paint, dry times will vary considerably. For example when you compare acrylic to oil paint, the dry time is mere hours versus months (or even years) for oils.
But in general you should wait 6 months to a year before varnishing an oil painting. Unless you use Gamvar; the seemingly magical varnish that’s ideal for impatient artists. More on that later…
With most varnishes, the paint should be hard-dry, which is something you can test with your fingernail. If you can gently press your nail into the paint, leave a small dent, then buff that dent out with a soft cloth, your painting is ready to varnish.
If you don’t let the oil paint dry completely, the varnish can actually leach into the finished painting, becoming impossible to remove later without permanently ruining your artwork.
Synthetic Versus Traditional Varnish
Not all varnishes are created equally. Some are made with natural materials while others are man-made.
There are two main types of varnish: traditional and synthetic. Let’s look at the differences.
I’ve already mentioned the oldest traditional varnishes (Copal, and Amber), which are notorious for yellowing and cracking over time. These “hard natural varnishes” become harder the older they get and can’t be removed with solvents. Instead, you have to use heated oil which can be a tricky process. It’s nearly impossible to find them today since they’re made from fossilized tree sap, a very scarce resource.
There are also two others that fall under the umbrella of traditional finishes.
Mastic and Dammar (Damar) are “soft natural varnishes” that stepped into the scene in the 18th and 19th centuries. They’re made by dissolving tree resin in a solvent and mixing it with oil. These varnishes also yellow and harden with age, but the key difference is they can be removed carefully with the help of a solvent.
As you travel further down the timeline toward the present day, you’ll find modern varnishes. AKA mineral spirit acrylic varnishes (MSA). Today, we have many synthetic varnishes designed to be non-yellowing, flexible, and easy to remove if needed.
They come in various levels of shine, from matt to high gloss and can be applied with a brush or sprayed from a can in aerosol form. Most synthetic types have to be applied after a painting is entirely dry, but one unique formula has time-crunched-artists jumping for joy.
Now you can varnish in even less time with the Gamvar varnish I mentioned earlier. This miraculous varnish can be applied when your painting is only touch dry, not completely dry (or hard dry).
When the thickest layer of your painting is firm to the touch, you’re safe to apply Gamvar. Plus, it’s removable with Gamsol. It’s a must for artists who want to get the job done ASAP.
Are There Different Kinds of Varnish?
Thanks to modern technology, applying varnish has become a pretty streamlined process. There was once a time when you could only create varnish from sap, and it was almost sure to yellow.
Nowadays, the synthetic options come in a spray can or a pre-made liquid form that stays clear permanently. Plus, both forms range in sheen from flat matte to high gloss. Let’s dive into the differences between them.
Gloss varnish is an excellent choice if you want to accentuate and brighten the colors in your painting.
Winsor & Newton makes a spray or liquid gloss varnish that goes on clear and stays clear forever. It can also be removed easily with turpentine or mineral spirits if you don’t like the finish or you need a fresh coat later on.
Matt (or matte varnish) does the exact opposite of gloss. It brightens the darkest areas of your painting by scattering light.
The result? A flat-looking piece with toned down colors. It goes on clear and stays that way.
Matt is a great choice if you plan to photograph your paintings since you won’t have to wrestle with any glare, like you would with a high gloss varnish.
You can buy matte varnish in liquid or spray form and remove it with conventional solvents.
Satin varnish is right in the middle of gloss and matt in terms of shine and vibrance. It gives your painting a nice even coat of gloss without the mirror effect of high gloss varnishes.
Satin varnish can also be applied in a few thin layers as liquid or spray, and removed with solvents later.
If you prefer the old-style varnish and aren’t afraid of your painting turning a tad yellow, you can use a liquid or spray Dammar varnish. Some artists prefer the spray for varnishing large paintings since Dammar varnish can become tacky very quickly in liquid form.
Retouching varnish or temporary picture varnish isn’t used as a final varnish like the options mentioned above. Instead, it’s used to even out sunken-in areas that appear more matt than surrounding glossy areas.
A thin coat of it doesn’t stop your paint from drying, and can be covered with a permanent varnish layer later on.
You can use either liquid or spray retouch varnish over the entire painting to even out the sheen. But it should be applied sparingly since excess varnish can actually dissolve your not-yet-dry paint.
Don’t have any retouch varnish? As long as you have linseed oil you achieve the same effect with some patience and a clean brush.
Check out this video to learn how to restore your painting’s vibrance with linseed oil:
Once your painting is hard-dry and you’re happy with the effects of the temporary varnish, you can use a final picture varnish to seal your painting.
How to Varnish an Oil Painting With a Brush
If you choose to varnish your oil painting with a brush, I recommend a soft-bristled option that doesn’t show brushstrokes easily. For example, a decorator’s brush is too coarse.
Also, have a designated varnishing brush to ensure you won’t transfer pigments into the final layer.
You’ll also want to do this process in a well-ventilated space since varnishes contain hazardous solvents.
- Wide, smooth brush
- Tarp or cardboard
- Large, shallow dish
- Your hard-dry painting
Step 1: Set the Stage
Lay your tarp, cardboard, or protective plastic film down to keep your surfaces clean. Then, set your painting down, so it’s level. You always want to varnish flat, so there’s no chance of it running.
Step 2: Prep Your Varnish
Pour some varnish into your shallow dish and dip your brush in the liquid. Now, you’ll have to work quickly.
Step 3: Coat Your Oil Painting
Varnish straight across the entire surface in long, even strokes. Move left to right, working your way down the canvas. Avoid applying a thick coat – less is more at this stage.
Do NOT revisit partially dry varnish with wet. This can create a cloudy look over the dark pigments. Instead, revisit the area when you apply the second coat.
Step 4: Cover and Let Dry
At this stage, you’ll want to cover your freshly varnished surface WITHOUT touching it. You can elevate a piece of cardboard just above it to keep the area dust free as it dries.
Step 5: Repeat
Once your varnish layer is dry, add another coat perpendicular to the first strokes. Repeat steps 3 and 4 until you’re satisfied with the result.
Viola! a beautiful sealed painting.
How Long Does It Take Liquid Varnish to Dry?
Varnish typically needs to be applied in multiple thin coats, but each layer must be completely dry before applying the next. Generally speaking, you should let your varnish dry for 24 hours before you add another layer.
How to Varnish an Oil Painting With a Spray Varnish
Spray varnishes certainly shave time off of the process and eliminate the need for a brush. They still contain harmful solvents and should always be used where fresh air flows.
- Room temp spray
- Clean room
- Cardboard or plastic tarp
- Lint free cloth
Step 1: Prep the Painting
Before you start spraying, start by wiping your canvas off with a lint-free rag. Otherwise, you’ll also be preserving any dust or hairs on the surface. Then, set the ready-to-spray canvas on your tarp or cardboard.
Step 2: Shake, Shake, Shake
Next, shake your oil varnish as per the instructions on the can. They can vary slightly between manufacturers, so do your homework. Then, aim your spray can at the cardboard behind your canvas in the top left corner. (You don’t want to start spraying directly on the canvas since the mist can pool and drip).
Check out this video to see an example:
Step 3: Spray Away
Start spraying a steady, even stream and move across your canvas from left to right. Work your way from top to bottom until it’s evenly coated.
Step 4: Let It Dry and Repeat
Fortunately, a sprayed coat of varnish dried quickly, so you won’t have to wait long to apply the second coat. Once the surface is no longer tacky, repeat steps 2 and 3 until you’ve reached your desired gloss.
You’ll probably only need 3-4 coats, but some artists use 20-50 for maximum gloss.
How Long Does Spray Varnish Take to Dry?
A coat of spray varnish takes around 10 minutes to dry, saving you a lot of time when compared to the liquid form.
You really only need 2 or 3 coats to protect your painting, and you should let each one dry fully before applying the next.
How to Remove Varnish
There may come a time where you, or a future fanatic of your art, might want to strip the varnish off your painting if it’s dirty, yellowing, or cracking. (This step is like removing the dirty gardening gloves we discussed earlier).
Once removed, a new coat can be applied to protect your painting once again.
Assuming your painting is protected with a removable varnish, you can safely remove it with a solvent like distilled turpentine. If you’re worried about damaging your piece, you can always take it to a professional conservator, but if you want to do it yourself, this section is for you.
Here’s what you’ll need:
- Lint free rag
- Cotton swabs
- Rubber gloves
- Plastic tarp or drop cloth
- Solvent (mineral spirits or turpentine)
Step 1: Lay the Groundwork
Roll out the plastic mat, put your gloves on, and lay your painting flat on the table. You don’t want solvent to run, so make sure it’s level.
Step 2: Apply the Solvent
Next, apply a little solvent to a lint-free rag or cotton swab. Gently saturate a small area of the canvas, preferably one that’s discrete. This way, you can test how the varnish behaves. Let it sit for a minute or two until the varnish liquefies. If it’s stringy or tacky, wait a little longer.
Step 3: Reveal the Painting Underneath
Wipe the solvent away with your rag or cotton bud to remove the varnish from the surface. If you see any red flags, like pigment from your oil paints coming off, stop right away and reach out to a professional. It’s better to be safe than sorry since any damage can be permanent.
But if the process is going swimmingly, keep blotting solvent until you’ve removed every bit of varnish.
To Varnish or Not to Varnish?
Varnishing oil paintings isn’t a requirement, and not every artist enjoys the look of it. Hey, even Monet opted out.
Although varnish does change the look of a painting, the tradeoff is excellent protection from UV rays and dirt that can cause permanent damage. And both of those risks are pretty much inevitable if you display your artwork outside of a museum.
Considering modern-day varnishes are removable, it may be worth testing a spray or liquid on a piece of art that you’re ok experimenting with. If you don’t like the look of it, you can always remove it with the help of a solvent.
But the best case scenario is that you fall in love with the accentuated colors a coat of varnish can provide and feel satisfied knowing your art is well protected.
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