The Ultimate Guide to Varnishing an Oil Painting: Teach Yourself

Varnishing an oil painting is a finishing touch that can take your artwork to the next level. It seals in the paint, creating a glossy finish and protecting it from dust or dirt.

While varnishing an oil painting is a relatively easy process, it’s important to do it correctly. This article will answer questions about how to varnish an oil painting and give you tips that will help you get the most out of your varnish. You’ll also learn how to choose the right type of varnish for your needs and what not to do when varnishing! Let’s get started!

What Does Varnish Do?

Oil paints contain certain resins (oils that have solidified) which give them their texture, body, and appearance. Varnishing oils gives us a way to blend these small particles together into an even layer on top of the paint while also preventing dust or dirt from settling in there as well!

Why Should You Varnish an Oil Painting?

To Unify Surface Quality

By adding a varnish, you make the surface of your painting smooth and glossy. This creates an even appearance and unifies all the different elements in your piece.

To Protect Against Dirt or Dust

Over time, oil paint can absorb natural skin oils from hands that touch it (even if they’re clean). The result is discoloration on the painted surface which makes for a less attractive work of art! Varnishing acts as a protective layer between these oils and your painting so this doesn’t happen.

To Add Depth to Color Application

If you’ve used thin glazes over already-dry layers of paint, there may be some areas where thinner pigments have lifted off with each successive application of new layers above them.

Applying a coat of varnish can blend these layers together, lending the appearance of depth and richness to your painting.

To Add Sheen or Glossiness to Color Application

Sometimes artists will want their paintings to look less glossy than usual in order to convey certain atmospheres (dusty desert scenes come to mind). In other situations though, you might actually want some shine! Varnishing is a great way to achieve this effect if it’s something you’re going for.

Types of Varnish

There are lots of different kinds but here’s what you’ll most likely come across:

Oil-Based Varnishes

These consist mainly of ingredients like alkyd resin dissolved with alcohols such as methanol or ethanol. They act more slowly than water-based ones so be sure not to apply them too liberally. Once they’re dry, however, oil varnishes can produce a very hard and durable surface that is also resistant to dirt or dust!

Water-Based Varnishes

These have resins dissolved in water with additives like alkyl acetate or ethyl lactate for quick evaporation once applied.

They are usually less glossy than their oil counterparts but they don’t yellow over time the way that some oils do (making them good choices when you want your work of art to retain its original color).

This lower gloss level makes it easier for artists who use thin glazes in layers on top of each other because it’s not as reflective when viewed from an angle—the paint beneath will still be visible through it.

Which Varnish Should You Use?

Well, that depends on what kind of painting you’re doing! For example: If your artwork has lots of heavy impasto (thickly applied paint) then an oil-based varnish might be the way to go so that it doesn’t seep into all those nooks and crannies in your brushstrokes!

On the other hand, if you’ve used thin layers over already dry paint or plan to frame your work under glass instead of hanging it on a wall, water-based varnishes tend to give paintings a more even appearance overall with fewer color distortions from refraction when viewed at an angle.

Both types have their pros and cons but either will make a world of difference in the appearance, durability, and overall quality of your artwork!

Common Questions about Varnishing Paintings

What Types of Finished Surfaces Can Be Varnished?

Almost anything! For oil or acrylic paintings, don’t hesitate to use either an alkyd-based varnish (gives the most luster but is also more likely to yellow over time) or one made with a synthetic resin if you want something that dries harder and will be less sensitive to humidity changes.

It’s always best practice though to test any sort of varnishing on a small area first before applying it all over your artwork for maximum results—and remember that some paints are only compatible with certain types so read the labels carefully before getting started.

How Long to Wait Before Varnishing an Oil Painting?

It’s best to wait until it feels completely dry, which usually takes anywhere from a few days up to several weeks depending on how thickly your paint was applied. Just be sure that you don’t rush the drying process though by using heat or putting something heavy over top of it with high humidity in the air because this can cause warping, bubbling, and other forms of damage instead.

If you notice any areas that are still wet, be sure to let them air out instead of covering them over top with something else until they’ve dried!

You may like our article about How To Make Oil Paints Dry Faster.

What Tools Do You Need to Varnish a Painting?

The bare essentials are just a brush to apply the varnish and something clean to wipe excess off with (like an old, soft t-shirt or rag). Smooth surfaces like acrylics can usually be done quickly with one swipe but for oil paints, you’ll need something denser so that it doesn’t leave any streaks behind—and always remember to work in small sections at once instead of doing the whole thing all at once!

How Many Coats of Varnish to Use?

The answer here varies from person to person because it depends on how much luster and protection they’re looking for as well as what type of paint is being used (oil vs water-based) but generally speaking, at least two coats will help protect against most types of damage including fading over time when exposed to light—and the more you apply the better!

Just be sure that each layer has had enough time in between before applying another coat so that it doesn’t start dissolving into whatever was underneath earlier despite drying out properly.

Also in mind that one thick application of a really high-quality varnish can work almost as well as several thin ones if you plan on leaving it for years to come!

How Long Does Varnish Take to Dry?

It takes roughly the same length of time as drying your paint layer by layer so anything from a few hours up until several days depending on how much you apply—but keep in mind that it’s always best to err on the side of caution when using any sort of chemicals or commercially-available products because there can sometimes be unexpected chemical reactions occurring between different brands if applied too closely together.

If unsure about whether or not your layers have dried fully, try seeing if there’s a tacky or slightly sticky feel to them instead.

How to Varnish an Oil Painting on Canvas

Now that we know why varnishing an oil painting matters, let’s talk about how you go about doing it.

Varnishes can be applied using brush-on or spray sealant which are both equally effective for protecting your work depending on what you might prefer instead.

How to Apply Varnish with a Brush

Varnish can be applied with either a bristle or foam brush and it should always be used in the same direction as your painting so that you don’t leave behind any streaks.

Use an old, soft brush (like one made with natural hairs) to apply it in thin layers—and don’t forget that you can always use a rag or t-shirt for the same effect if you want something even simpler

Just remember to clean out excess before applying another coat if necessary and work in thin layers at once rather than trying to do everything all at once—and don’t forget that varnishing works best when done over top of one final layer of paint!

How to Apply a Spray Varnish

A spray varnish is a great way to seal oil paintings because it’s easy and quick to use, but be sure that you shake the can for at least a full minute before applying—and never apply from too close or in circular motions!

Start spraying from about 12 inches away while moving steadily across the surface until every area is covered without any pooling of liquid forming anywhere else. You should also try not to hold it over one certain area of your painting for more than several seconds per time as well.

Problems That Can Arise When Varnishing Your Oil Paintings

While varnishing your painting will provide an extra layer of protection and help maintain its appearance for decades, it’s not without downsides.

It might cause darkening or off-coloring in the long run if applied too thickly and there can also be unexpected chemical reactions occurring between different brands so always test first before applying over top—and never apply to bigger sections than you’re comfortable with because once you start, there’s no going back!

Beading or Smudging

If you see your varnish bead or smear when it’s dry, don’t worry! Just wipe the surface clean with a cotton ball soaked in mineral spirits and try again.

If that doesn’t work, however, there might be something else going on underneath so double-check to make sure everything is fully dried before attempting another coat—and if all else fails after doing this, just leave it as is because those little imperfections can sometimes add character over time instead of causing damage.


Bubbles can be a big problem when you’re varnishing oil paintings because they either mean that the paint is still damp underneath or there’s too much moisture in the air from humidity.

The most common way to prevent bubbles is by stirring it thoroughly before application in order to mix air trapped inside with whatever liquid has been added which helps reduce any chances that they might appear.

Adding too much chemical at once can also cause them though, as well as letting layers dry out fully between coats—and never shake when opening!

To check, look closely to make sure it isn’t just tiny beads of water. If everything else has been taken care of but bubbles are persisting then try using a hairdryer to make them rise up and pop themselves instead!

You might also be interested in our article about How to Remove Oil Paint Off Skin.

Tips About Varnishing Oil Paintings

  • The key to successfully varnishing oil paintings is to do so slowly and carefully in thin layers at a time.
  • Do not varnish your paintings before they’re fully dry. This will trap in all the moisture and cause damage to the paints underneath.
  • The number of coats applied depends on factors including the type used (oil-based versus water-soluble), temperature, humidity levels, etc. While three might work for some people, others may need five or six most during one session depending on the color.
  • Avoid using varnish on larger sections than you’re comfortable with because it can easily cause damage when applied too thickly.
  • Work from sections down over the top of one final layer because it’s always better to have too little than too much, and if you use several coats instead, be sure that each one has dried out fully before applying another.
  • You should also keep humidity low by using air conditioning during the summer months which will help prevent warping due to moisture buildup inside the room while keeping heat sources like radiators and fireplaces out.


Varnishes help protect your paintings from dirt or dust collecting on top but won’t do much against sunlight damage instead, just remember though that any extra time spent waiting won’t necessarily be wasted if this is allowed for aging first before storing away. Plus the proper application of additional layers means more protection, especially when used correctly.

Leave a Comment