Varnish is the final step for painting. When I just started I was terrified – there were so many contradictory posts about varnishing but all of them said, you could probably ruin your painting…Wait, what?
Why varnish acrylic painting then and should I varnish my acrylic painting at all? I avoided varnishing for a while but one day I decided just to try on a small painting. And that was amazing!
The varnish will protect acrylic painting from dust, UV rays, water, scratching and yellowing.
You absolutely should varnish your finished acrylic painting: the varnish protects acrylic painting during transportation, from sun, humidity, and temperature changes, but also varnish helps color vibrancy and makes my acrylic painting look better and finished for 100 years.
After all, cleaning a varnished painting is so easy!
Even though, Smithsonian Institution doesn’t recommend varnishing acrylic paintings, it is actually vital to apply a protective finish over your acrylic work to save it from UV and time.
Here is why I decided to share with you all I know and researched to make sure you are not scared anymore.
I will start with a brief reminder of what is varnish and what types of varnish exist and cover 6 major reasons why you should consider varnishing your acrylic painting.
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Start painting today: How to Paint with Acrylics on Canvas: 3 Easy Steps [Supplies included]
What is varnishing?
A varnish – is a transparent protective layer on our painting. It forms a hard, clear, shiny surface when dry.
Varnishing an acrylic painting means covering a finished and completely dried ( ±24 hrs.) painting with several coats of varnish.
Varnish layer should go over isolation coat to avoid any surprises!
What type of varnish to choose?
Varnish can be removable (which is better) and non-removable (permanent).
They also can be divided based on composition.
Types of varnishes:
- mineral spirit acrylic varnish – tougher varnishes, less permeable (allow less water to get in), more durable, but also can be trickier to apply and smell bad. Varnishes with mineral spirits can be removable with turpentine and are suitable for both acrylic and oil paintings. Before applying varnish with mineral spirit, use isolation coat. Good choice for paintings stored or displayed outside, but excessive for indoor paintings.
- acrylic varnish has a similar to acrylic paint composition – it contains acrylic polymer emulsions that create a strong protective satin or matte finish. Perfect choice for most paintings. Acrylic polymer varnish is also largely available.
- BUT, traditional oil varnishes are great for oil paints but they are no good for acrylic paints. Oil varnishes vs polymer varnishes are historically made from damar, resinand use solvents that can ruin acrylics. This is why moving forward, brands created isolation coating to protect paint itself from interacting with varnish and special polymer varnishes for acrylics that won’t ruin the painting. So no, oil varsnihes can not serve as top coat for your acrylic painting.
- There are also some craft varnishes like Mod Podge (I consider it craft varnish as it basically glue mix) that work great on wood panel, some fabrics and other less traditional surfaces. Most of them are non-removable. Mod Podge comes in saying finish and matter version. For sealing paint on wooden surfaces like furniture people normally use cold wax and polish it with damp cloth, but it doesn’t work for acrylic painting a canvas surface!
Basically, you need to remove and repeat varnishing every 5-10 years, because varnish collects all dust and dirt and can become yellow over time.
If you’ve chosen permanent varnish you won’t be able to remove it and save your painting for longer years.
If you will still try to remove permanent varnish, you can damage your painting.
Varnish can has matte, satin, gloss or high gloss finishes:
- Glossy varnish slightly enhances the colors vivacity, gives shiny finish and reflects light. Dark colors, black paint work best with glossy finish varnish, semi gloss and satin varnishes.
- Satin finish. Satin varnish soften the colors, offers less sheen; Satin varnishes are the best go to option, not too shiny, not too dull. Prefect for beginners. In a separate article on finishes I compared satin vs gloss choices in varnishes.
- Matte varnish. Matte varnish may make dark colors lighter and has no gloss at all.
To learn more about differences in finishes and their advantages, check my comparisons: Satin vs Matte: Which Paint Makes for a Good Finish?
You can choose any based on your preferences or mix them to achieve the desirable effect.
Natural varnishes (damar, mastic) can yellow over time.
Synthetic varnishes can discolor over time.
If you notice it, just remove and replace varnish.
There are also water and solvent-based varnish. Solvent-based varnish is a bit harder in use but also create stronger protection.
I use water-based removable Golden, Winsor & Newton or Liquitex varnish.
If you need more recommendations for a particular varnish, check my How-to guide on varnish an acrylic painting.
Should I varnish My acrylic painting? 8 Reasons to Do it.
First of all, varnish is not mandatory but a recommended way to protect your acrylic painting.
An alternative ways to varnishing are placing your painting under glass or leaving it without varnish.
Fun fact: Pissaro and Monet preferred the unvarnished look as many Impressionists. Picasso and Van Gogh also didn't like to varnish their paintings.
The reasons why varnish acrylic painting are numerous:
- Varnish protects the acrylic painting from dust and dirt.
- Varnish doesn’t let moisture inside.
- Varnish protects the painting from extremes of temperature or humidity and UV radiation
- Allows easy cleaning process.
- Varnish makes colors more vibrant and increases color saturation
- Varnish makes the surface even and creates that feeling of accomplished work.
- Varnish makes your painting last longer (dozens of years) due to removal options.
- Acrylics are generally not as hard as oils so they need protection. The best protection for museum pieces is glass or plexiglass, but for smaller collections and personal use varnishing acrylic paintings saves the day.
1 – Protection from the dust
During the drying process and even being fully dried, acrylic paint stay soft and allows dust and dirt to adhere to the painting surface.
As we remember, acrylics are water-based and the drying process is the simple process of water evaporation.
When water evaporates, the other ingredients of the paint, such as agents and mostly binder (polymer) join together to form a film.
But while drying small pores appear. These micropores are very happy to collect dust. This is why varnish can save us – it creates a non-porous hard coat!
This is how much dirt can collect varnish over time.
We can also see that it’s yellowing and why it is important both to apply and to remove and replace varnish when the time comes to protect and save our paintings for 100 years.
Pro Tip: Take photos and notes to know exactly when you varnished your painting and what varnish you used. When you will need to remove it, you will read the brand's instructions. Plus, looking at photos you can directly tell if it is time to replace the varnish.
If you choose to varnish your acrylic painting, you don’t have to put your painting under the glass. Painting without glass looks more natural and modern for me.
I also don’t like the glare that glass gives while you look at the painting.
2 – Protection from the environment
A dried varnish is a hard protective layer, it is harder than cured acrylics which means it assures better protection.
- extreme temperatures
- extreme humidity
- UV protection
Remember the ideal environment for painting:
Temperature: 65-75 degrees Fahrenheit (18 – 24 C). Humidity: 40-50% Well-aired room
A hard varnish coat will protect the paint from drastic changes in temperature or humidity but it still doesn’t mean that you can store acrylic painting in an inappropriate environment.
Nowadays, most varnishes contain Ultra Violet Light Stabilizers that disperse UV radiation before it hits the surface of a painting.
Varnish prevents fading and yellowing of the paint.
The protective properties of the varnish are also useful for transportation.
If your paintings are for sale or participate in exhibitions, varnish will protect them from light eventual damages.
3 – Cleaning
When an isolation coat and varnish are applied correctly, the painting will be able to be cleaned easily.
Just wipe the painting down. The surface is water resistant but don’t soak it with water 🙂
Without varnish cleaning can remove or damage the paint film.
4 – Gloss and color vivacity
Remember the perfectly clean white floor, and it seems bright, brand new, and glossy?
Varnish does the same for your painting. Over time, this is a varnish that still makes your painting looks great, and colors – rich.
To assure the right level of the gloss, just mix matte and gloss finish or use directly gloss varnish.
The matting agent is white and sometimes will leave a milky finish to your paintings. Make sure you mix it properly.
Varnish creates a permanent enrichment to the colors. Even if you’ve just finished your painting and it looks great, fresh, and bright, acrylics will dry and lose a bit of their gloss.
You can use acrylic paint with more gloss like Winsor & Newton but only a varnish will make gloss and color saturation permanent.
Many artist, especially who work in photorealistic technique, rediscovered the beauty of their paintings after varnishing.
5 – Even and unified surface
Every brand and paint has different amount of binder and pigment in it. Some brands create low sheen or extreme sheen paint.
The amount of water you add to dilute paint will also affect its sheen.
Different acrylic mediums also have different shine rate. For example, you mixed paint with matte medium to create some objects and then used extreme sheen white.
As the results we have uneven surface with areas with different shining.
Varnishing will smooth all these differences and create even and unified look, that we and other people will perceive as something finished and beautiful.
A nice coat of varnish is the easiest and most effective way to make your acrylic painting look great!
6 – Longevity
Varnish is a key to make our creative heritage last longer.
Once we finished our work we should think how to make sure it will live long life, especially if you create it for sale.
As we know varnish protects acrylic painting from dust, environment, enriches colors but also, we apply varnish first of all, to remove and replace it later. Such an irony, that something is useful because we can remove it!
Removing and replacing varnish can give your painting hundreds of years.
Before applying a varnish make sure you applied isolation coats!
is varnish necessary for acrylic painting?
Varnishing acrylic painting is highly recommended, but there is still a lot of artists who do not varnish their acrylic paintings at all.
The oil tradition is ancient, but the acrylic one is considered young.
We still don’t know what is the best way and adjust oil techniques to acrylic properties and logic.
It is your own decision, creative experiments, and knowledge that will suggest the best way.
Varnishing a painting will protect it but also has some eventual negative effects which beginners will probably very happy to avoid.
Make sure to use compatible acrylic varnishes.
Varnishing acrylic paintings FAQ
Does varnish ruin acrylic paint?
Acrylic varnishes applied over isolation coat on acrylic paintings do not ruin acrylic paint but preserve it for long years.
However oil varnishes, non removable varnishes, lack of isolation coat, applying varnish on wet acrylic paint can ruin your acrylic painting.
Do you need to varnish your acrylic paintings?
It is not mandatory varnishing acrylic paintings especially if you don’t like the outcome.
However, if you are planning on hanging the painting, selling it or trying to protect it from dust, sun and humidity for decades, you should consider one of the varnishing options: removable varnishes, spray varnish, epoxy or polyurethane finish.
Is it okay not to seal an acrylic painting?
It is absolutely normal not to seal or varnish an acrylic painting but it is highly recommended by professional artists.
Once the acrylic paint dries it becomes water-resistant so you can still safely clean it.
You can also put your painting under the glass to protect it from dust if you don’t want to varnish it.
Or you can just leave it be! Especially if you think you may reuse the canvas (paint over this painting) or make some changes to this painting.
If you choose to varnish your acrylic painting, please do it in a well ventilated space, apply the varnish wearing protective gloves and only on a completely dry paint.
If you are using a varnish, apply a few layers, every time wait a few hours until the varnish dries and only then add second layer.
How long should I wait to varnish an acrylic painting?
The best practice is to wait the full 24 hours after painting, to let acrylics dry completely.
While it seems like it is dry within 20 minutes it is only dry to touch at this point and varnishing acrylic painting will lift and move all underlying paint and it will ruin your painting.
Also, some brands and acrylic paint types are slow-drying like Golden Open, and it may take a few days for them to fully dry.
Always read the label or even the date sheet on the brand’s website. Here I gathered drying times (to touch) of 30+ acrylic paint brands.
Do not ever apply any varnish over fresh wet paint.
What should I seal my acrylic painting with?
To seal your fully dried finished painting you can use products from art stores that say “varnish” for acrylic or oil painting. It can be a milky liquid that will dry to a transparent finish or a spray.
I recommend spray varnishes for beginners.
You always need to use removable varnish to seal acrylic painting as non-removable varnishes cannot be scraped off the painting and if it yellows, you cannot do anything about it.
Before varnishing, apply an isolation coat to protect the paint layer, let it dry and only then apply acrylic painting varnish in thin layers with a varnish brush – it should be a separate flat large brush.
What are the benefits of varnishing acrylic paintings?
Great even sheen, smooth surface, long lasting protection (we talk years) from dust, UV, scratches, spills or anything, it also protect the edges.
Varnishing gives a finished look to your acrylics painting and makes the cleaning very easy.
Is it necessary to varnish acrylic painting before framing?
If you areplanning to frame your acrylic painting with glass or acrylic sheet you can skip varnishing. The glass will protect the painting from dirt and dust.
However, regular glass does not protect from UV. To protect acrylic painting from sunlight, use plexiglass which absorbs around 60% of UV rays.
How many coats of varnish should you put on an acrylic painting?
It is a good practice to apply 2 to 3 coats of varnish on an acrylic painting, letting each coat fully dry for at least 4-5 hours, but better overnight.
In between layers check for bubbles, hair or other small things that can
Can we use wood varnish on acrylic painting?
Even though wood varnish is not made for acrylic painting on canvas, you can use wood protective finishes to seal acrylics.
For example, Minwax finish is a popular option to varnish acrylic painting but it is in fact a polyurethane protective clear coat for wooden furniture.
Can I use oil varnish on acrylic painting?
If you have on oil varnish made of resin, damwar or it says it is a non-removable varnish, do not use it on acrylic painting.
They can yellow or destroy underlying acrylic paint layer. Opt for polymer or acrylic varnishes for acrylic painting.
Can you paint over a varnished acrylic painting?
Technically you can paint over a varnished acrylic painting in a few cases: when you are doing only small edits or when you prepared the surface.
If you need to paint over a large area, I recommend removing the varnish first.
If your varnish layer is glossy and it is a polymer film (most acrylic varnishes are polymer) then paint won’t stick to eat without preparation and will peel off.
If you painted over varnished painting, you need to varnish it again.
be stuck in paint or varnish and remove them before applying the next layer with tweezers.
If you are ready to varnish your painting:
You will need a flat separate brush, a clean jar or container, and a well-aired clean workplace.
You can use polymer Golden varnish, Liquitex varnish, Golden MSA varnish, or Grumbacher spray varnish.
The step-by-step guide for varnishing How to Varnish an Acrylic Paintingg with a brush, with a spray, or how to remove varnish.
To sum up all benefits of varnishing acrylic paintings as some final thoughts:
- we have a complete painting with smooth, even sheen (whether you choose satin finish, matter or gloss).
- we did acrylic painting in the most professional way
- the main benefits of varnishing an acrylic painting are of course UV protection, dust and moisture protection, professional look and guarantee of its longer life.
- our painting is easy to clean and it won’t let moist inside or be affected by changes of temperatures.
- varnished painting will be ok during transportation or storage.
- varnishing is a way to make acrylic painting look shiny if you use gloss medium and gloss varnish.
Whether you will decide to varnish your finished masterpiece or not, it is a great idea to actually know your options and why people seal or prefer not to their paintings.
I can say that now you definitely know more about different varnishes and I hope it helped make a decision on how to protect your own painting.
Masha Eretnova is a certified teacher. She started painting and drawing 20+ years ago and now is an international abstract artist and educator passionate about acrylic painting, gouache and crafts.
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