How to Seal an Acrylic Painting With Absolute Confidence

Spray vanish and brush-on varnish with a flat brush

To seal an acrylic painting or not to seal an acrylic painting, that is the burning question. If you asked a room full of artists this question, you’d have to stop, drop, and roll for the number of flames that would be shooting out of everyone’s ears, haha! But, seriously, whether to seal an acrylic painting is a pretty split decision.

Personally, I almost always seal my paintings unless it’s just a practice in my art journal. Sealing an acrylic painting is my preferred method because:

  • It makes the colors pop
  • It helps with UV protection
  • It makes it safer to handle
  • It doesn’t grab onto dust as easily
  • It evens out the finish for a consistent sheen (if you’ve used a medium for blending that dries glossy. You can check out my tips on how to blend acrylics here)

To seal an acrylic painting, you have two choices. You can either use a spray varnish or you can use a brush on varnish. Both have their pros and cons and some things to keep in mind no matter which way you decide to go. Let’s get down to the nitty gritty, shall we?

How to Seal an Acrylic Painting

But First, Should you Use an Isolation Coat?

Extreme close-up of a painting, showing the shine from an isolation coat.

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

A person pouring resin onto a bright blue circular painting. Titled "Choose your 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

Stacked white spray cans to represent 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

Brush-On Varnish

Multiple flat brushes with turquoise, royal blue, lime green, and purple paint dried on them. Titled "Sealing with a Brush".

When you seal an acrylic painting using a brush, there are a few more things to consider but it’s worth giving it a go especially if you don’t have space to spray or you can’t stand the fumes.

To really have success with brush-on varnish, using the right tools will make all the difference. It is possible to get a streak-free finish but you’re going to have to find some extra patience.

BUYING A VARNISH BRUSH:

To seal an acrylic painting with a brush-on varnish, your brush is either going to be your best friend or your worst enemy. You can buy actual varnish brushes but it’s not really necessary unless that’s the way you want to go.

There are lots of brushes that you can use to seal an acrylic painting right at your local hardware, or building supply, store.

BRUSH BUYING TIPS:

  • This is not where you want to go with the motto of “cheap is best”. You want to get a high quality brush so you’re not endlessly picking bristles out of the varnish as you seal the painting
  • Look for a wide brush with nylon bristles
  • Don’t be afraid to ask the staff what they would recommend to seal an acrylic painting. They can save you a ton of time and keep you from getting overwhelmed by a gazillion choices

HOW TO CREATE A SMOOTH FINISH:

Exttreme close-up of a section of a painting that is different shades of blue. This has quite a high reflection that shows an example of how to get a smooth finish when you seal an acrylic painting.

This is the most important, and challenging, part of trying to seal an acrylic painting with a brush. The biggest complaint I see is that brush-on varnish leaves brush strokes or gets cloudy. The reason you get brush strokes is that the layer is too thick. You need to work in very thin layers.

Cloudiness on your painting is due to over brushing. What I mean is that you’ve gone over a spot too many times at once and the varnish was already starting to dry. Just try to remember, go over it once and come back and add more after the first layer has dried.

TIPS FOR CREATING A SMOOTH FINISH:

  • Lay your painting flat so you don’t get drips
  • Dust your painting with a clean dry brush to get rid of any debris
  • You don’t want to load your brush too full. Remember, you want to do this in very thin layers
  • Use long strokes, starting at the top, to go from one side of the painting to the other
  • Once you lay the varnish down on the painting, don’t go over it if you can help it. Come back to it later and add another coat
  • When you’re ready to do another coat, turn your painting 90 degrees and repeat the process. Think of this as completing the first coat
  • Repeat as many times as necessary until you feel happy with the result

Final Thoughts

You’re going to see a lot of different methods on how to seal an acrylic painting and there is no one right way. Don’t be afraid to experiment and find your own technique.

Although you don’t have to varnish an acrylic painting, I highly recommend at least giving it a try. It creates a uniform sheen, protects your painting from dust, and gives your painting an extra depth.

If you’ve spent hours creating a beautiful work of art that you plan to showcase in your own home or give as a gift, varnish is a must!

Remember to take your time, use quality tools, and read the label. For real, READ. THE. LABEL.

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