I do want to interject here that there are many methods to seal an acrylic painting. I am just sharing how I do it.
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How Should I Seal An Acrylic Painting (Archival)?
September 17, 2020
Leaving the protection of an artist’s artwork up to chance is not a smart idea especially when considering acrylic paintings. These paintings are susceptible to dust, dirt, and other things that could ruin the painting. The best way to avoid ruining an acrylic painting is to apply sealant to your painting.
The best ways to seal an acrylic painting is to use an acrylic resin varnish, acrylic polymer varnish, clear sealer, or mod podge, depending on the surface you are painting on.
To avoid confusion, the word varnish can be used to refer to a traditional, oil-based finish or a general term for any finish. In this article, varnish will be used as a general term to mean “protective coat”. Let’s dive in.
How to Seal an Acrylic Painting
An isolation coat is a clear medium that goes on after your painting is dry but before you varnish. The purpose of an isolation coat is to create a non-removable layer of protection between the painting and the varnish so that, if there is ever a need to remove the varnish, it can be done without harming the painting underneath.
This isn’t something that you have to do but I always do it just to give me peace of mind that the painting that I worked so hard on has an added bit of protection. I use Liquitex Gloss Medium & Varnish, which is now called “Liquitex Professional Gloss Medium” and you can read more about it here, on the Liquitex website.
Before you decide to add an isolation coat, you should educate yourself on when to use one as it can interfere with the artistry of the painting in certain circumstances. You can read more about that on Golden’s website here.
Choosing a Finish
Before you seal an acrylic painting, you need to choose which type of finish you want your painting to have. This will depend on where the painting will be hung and also personal preference.
FINISH TYPES:
- Matte – A matte finish is very flat and doesn’t do much to make your colors pop. You might consider this type of finish if you plan on hanging your painting in a bright area that gets a lot of light
- Satin – This is the finish I typically go with. It gives the paint colors lots of depth and it has a bit of a sheen that I feel is just right, not too shiny but not flat either
- Gloss – If you like sparkle and shine, this is the one for you! I think it would work beautifully in a dark area of your home, such as a room without a window
- Resin – I haven’t used resin yet but I love how it looks on a paint pour. Because it’s an epoxy (plastic), it gives a very high gloss finish that, in my opinion, looks fantastic on abstracts
Spray Varnish
Beginners tend to find spray-on varnish much easier to use when they seal an acrylic painting. It’s definitely the way you’ll want to go if your painting has a lot of texture. Trying to brush varnish over texture can create bubbles in your varnish and it won’t dry nicely.
You can find a variety of brands and finishes anywhere they carry artist paints just make sure you’re using one specifically made for acrylic.
TIPS FOR USING A SPRAY VARNISH:
- It’s gonna stink something awful so make sure you’re in a well ventilated area where lingering fumes won’t be an issue
- Make sure to shake the can vigorously and for the amount of time indicated on the label
- Use drop cloths, if you’re laying your painting flat
- If you plan on hanging the painting to seal, make sure that you’re doing it on a wall with lots of space and that you don’t mind getting varnish on (unfinished basement wall would be my pick)
- Be sure to take a big dry brush to dust your painting off before varnishing
- When you get down to business, start spraying off the canvas and use long strokes, ending off the canvas on the other side
- Don’t stay in one spot, keep it movin’! The goal is to do multiple thin coats so you don’t get any drips
- Follow the directions on the label for times and proper use
Prepare Your Painting
Make sure your acrylic painting is dry and cured. Depending on the medium you may have used with your acrylic paint as you painted and how thick the layers of paint are, drying time can vary.
Varnishing over paint that may be dry on top yet not cured through could result in cracking, peeling, or other mishaps that you wish to avoid.
Your painting is dry?
Make sure your painting is done. Meaning, is there anything you wish to change or fix before sealing?
Varnishing is permanent, so make your changes before applying a varnish or sealer.
Great, now give it a good wipe with a soft clean cloth to make sure there is no dust or debris on the surface. This helps with better adhesion.
Apply the Varnish or Sealer of Choice
Now it’s time for the fun part: applying the sealer!
If you’re using varnish, pour a small amount onto the clean surface of your painting in the center.
Use a soft brush to spread it outward toward the edges going in one direction. I may start brushing horizontally first.
You can also put the varnish into a clean dish to dip your brush into then apply but I find this method faster and easier. The choice is yours.
Apply to the entire painting.
Go around the outer edges to make sure none dripped over.
Let dry thoroughly according to instructions on the varnish you use. Different types may require different drying times between coats.
Add Second Coat to Seal Acrylic Painting
Some feel fine stopping with one coat but I like to be doubly sure of the protection varnish provides so two coats are my preference.
Two thin coats work better than one thick coat.
As I said before, let the first coat dry, it may take 12 hours or more. Apply the second coat of varnish the same way you did the first but stroke vertically instead of horizontally.
If that is confusing please see the step-by-step video below!
