Gouache paint is sometimes preferred over watercolors because they work in the same way, but gouache paint is more opaque. Gouache is a water-based paint, so it works well with water-based products to seal it. There are tons of different products on the market that work to seal paintings.
So, can you seal gouache paint with Mod Podge? Yes! Since Mod Podge is water-based like gouache, you can use Mod Podge to seal a gouache painting. It is a great way to protect your painting and create a strong surface for the paper. When applying, you will need to be careful not to brush over the same place more than once.
Before applying Mod Podge to a gouache painting, you will need to make sure it is completely dry. Since gouache paint is water-based, it will become reactivated when it comes in contact with water. Mod Podge will work to protect the gouache from accidental water exposure, because it forms a slightly water-resistant layer.
How to Seal Gouache Paint

The process of sealing gouache with Mod Podge is very easy. It will keep the painting safe from dust, dirt, and sunlight that can be damaging to your artwork. You need to apply the Mod Podge very carefully to prevent reactivating the gouache after it’s dried.
You can use this Mod Podge to seal your gouache painting. Mod Podge also has many varnish options such as glitter, matte, satin and even a waterproof finish!
First, you will need to make sure the gouache paint is completely dried. If you apply the Mod Podge to the surface too soon, it can ruin the painting by causing the paint to run together into one large paint blob. This can be discouraging and frustrating, so you need to be sure the paint is dry first.
To be sure, you should wait several hours for the paint to dry before adding a sealant on top. When you apply the Mod Podge, you will need to do so very lightly. Load your brush with a small amount of product and lightly drag is across the surface of your paper.
I like to use this Mod Podge Application Brush, because it’s specifically designed for Mod Podge. Having the right type of application brush is always important, as it can ruin your painting.
It is important to make sure that you don’t apply too much product or too much pressure on one spot of the painting. This runs the risk of damaging your painting. You should move the paintbrush across the surface in one direction.
If you start at the top, move toward the bottom. If you start on the right, move toward the left. This will help you remember where you’ve already applied the Mod Podge, so you don’t apply more to the same area.
If you don’t want to use a brush on your gouache painting to avoid the risk of ruining it, there is a spray Mod Podge that you can use instead. You will get the same benefits of the brush on Mod Podge with none of the risk.
Why Does Gouache Crack?

There are two main reasons that gouache will crack. First, there wasn’t enough water used to dilute the paint. This will cause the paint to be thicker and more likely to crack as it dries. The amount of water that is needed will be different based on the color, so it will take some experimentation to get it right.
My favorite and top pick is always Arteza Gouache Paints. They have so many different colors, and the quality is amazing! I usually use Arteza Paints for all my projects.
Another reason gouache might be cracking has to do with the layers you paint. It is possible that the previous layer didn’t dry properly before adding the next one. The paint will crack as the layer below tries to dry at the same time as the top layer. The lower layer will shrink under the top layer, resulting in the cracking.
There is also the potential that you are applying your layers too thick. If you applied your first layer and let it dry before adding your next, but you notice cracks when you go back, the layer was likely too thick. Gouache can shrink as it dries, which causes thick layers to crack as they are drying.
Can I Use Acrylic Sealer on Gouache?
Acrylic sealers and gouache are both water-based products, so you won’t notice any issues with using an acrylic sealer. Acrylic sealers are offered as a brush-on and a spray formula. If you are worried about brushstrokes or applying too much pressure to the painting, a spray sealant will be a great option for you.
I like to use Krylon Acrylic Sealers on my paintings, because it offers great protection for chipping, flaking, and even UV rays.
If you are using gouache for a professional painting, you need to make sure you follow the proper process. This means that the final layer of sealer needs to be removable, allowing it to be replaced when necessary.
First, the painting will need to be completely dry before adding a sealer. When the paint is cured, you can apply your first layer of acrylic sealer. This layer is supposed to be permanent and not removable. This layer will make the art waterproof, protecting it from any potential water exposure in the future.
The second layer will be what’s called an isolation coat. This layer will also not be removable, but will prevent the painting from yellowing over time. This will also be an acrylic sealer as they are not known to yellow too much. The second layer also works to provide an extra protective layer.
When adding the final layer of sealer, make sure you have a specific acrylic sealer that is designed to be removed. They will protect your acrylic painting and trap any dust or dirt on the surface of the painting, preventing it from ruining your artwork.
With the two layers of sealer underneath the removable one, the painting will be completely protected when it comes time to remove and replace the top layer. This layer allows for the painting to be properly cleaned to extend its life.
Should Gouache Paint Be Varnished?

If you’re painting is going to be displayed somewhere, it is best to avoid applying a varnish to it. A varnish will alter how your finish product turns out. You will notice the depth isn’t as defined, the colors are darker, and the finish is different. Varnish is also permanent, so you won’t be able to make any changes to the art in the future.
You can apply the Mod Podge and Acrylic Sealer we talked about above, but that’s usually recommended if you will be keeping the painting in your home, or you like to varnish them. Many displays and museums don’t actually varnish gouache paintings.
Although you should try to avoid adding a varnish to your gouache painting, that doesn’t mean it should be left unprotected. To avoid adding a varnish to your gouache painting, you can place it in a frame behind glass. The best kind of glass that you can use for this is a museum grade glass. It will protect the painting from sunlight, fading, and yellowing.
When you put your painting in a frame, make sure you leave plenty of space between the painting and the glass. It will not be good for the painting to be pressed up against the glass. There won’t be enough room for the painting to breathe, and it runs the risk of growing mold or experiencing condensation.
Final Thoughts
Mod Podge and gouache are two popular art supplies that many people are curious about. One of the main questions asked about the products is whether they will work together or not. Since both products are water-based, you can use them together with no issues.
Applying Mod Podge on top of a gouache painting is easy but needs to be done carefully. Gouache has the potential of reactivating when you add Mod Podge to it. You will need to very lightly drag your paintbrush across the surface of the painting or use a spray Mod Podge to avoid brushing the Mod Podge on at all.
Make sure to follow all my tips and recommended products to ensure your gouache paint project turns out great! Also, don’t forget to check out my other articles for all your painting Q&A’s. Happy painting!