How to Varnish a Painting

Varnish is a transparent liquid that, when dry, acts as a hard protective coat for your painting. Made from tree resins, varnishes can also affect the colors of your painting, making them more vibrant.

How varnishes differ

If you were to walk into your local art supply store and head for the section where painting varnishes are kept, you'd run into several varnish options. While each type is different, the most important thing you have to know when choosing a varnish is this: Varnishes are categorized according to their finish, which is the amount of light reflected by the varnish once dry.

Varnish works well with oil and acrylic paints only. When applied to gouache or watercolor, varnish can absorbed by the paper or the paint, affecting the quality of the finished product.

How to choose varish

Gloss finishes reflect light and create a smooth glass-like finish which matches well with simpler paintings (in my personal opinion). Matte or satin finishes, on the other hand, won't reflect light, making them a good option for busier paintings with a lot of texture and patterns.

Ultimately, varnish is a personal choice and depends on how you want the finish version to look. Don't be afraid to play around on a practice canvas to see which finish you like best.

If you apply a varnish and find that you don't like the finish, don't worry! You can remove it, but you need to paint on what's called an isolation coat before the varnish.

An isolation coat is an additional layer that protects the varnish from being absorbed by the paint, allowing it to be removed at a later date if that is your wish.

If you're a hobby artist (like myself), you don't have to worry about using an isolation coat. Instead, you can apply the varnish directly to the painting.

Interesting in investing in an isolation coat? Try the Golden Artist Isolation Coat.

How to use an isolation coat

• If you decide to use an isolation coat, apply it directly to the painting and wait for it to dry. It should take anywhere from 10–30 minutes.
• Once it's dry, apply a thin layer of your varnish and wait for it to dry.

Boom. You have a protected painting that's ready for varnish.

As a painter, amateur or otherwise, you'll likely have a collection of brushes, but it's important to keep your varnishing brush separate from your normal paintbrushes. When varnish mixes with wet paint left on a brush, the diluted mixture can smear across the canvas. Keeping a brush specifically for varnish is a great way to keep this from happening.

But what kind of brush works best?

Most brush manufacturers and brands sell brushes specifically for varnish, but any wide flat brush like the Royal Brush Golden Taklon Paint Brushes will work well.**

Acrylic paints are sneaky. Even dry, acrylic paints are a lot more pliable than oil paints, which means they have a softer exterior that makes it easier for dust and light debris to stick to the surface. Enter the protective coating capacity of varnish.

However, this softer surface can also make varnish removal tricky. If you're even the slightest bit doubtful about your choice of varnish, you're going to want to use one of those handy-dandy isolation coats I described in the last step. Otherwise, you're ready to varnish as you normally would.

Remember: Always apply varnish in a well-ventilated room.

How to varnish an acrylic painting

• Pour your choice of varnish into a shallow bowl. I'm a huge fan of using small mason jars.
• Lay your painting, artwork up on a protective surface. Varnish likes to go everywhere varnish isn't welcome, but an old sheet, some newspaper, or a spare towel will help protect your workspace.
• Dip your brush into the varnish.
• Sweep the varnish lightly across the painting. Work side-to-side, slightly overlapping with each stroke to ensure an even coat.
• Don't re-varnish an area that you've already varnished. Dragging wet varnish through partially dry varnish can produce a cloudy finish.
• Apply an additional layer of varnish once the varnish is dry.
• Allow the varnish to dry completely.

First thing's first: You have to let your painting completely dry before you apply varnish.

If you've tuned into my How to Clean Your Brushes After Oil Painting guide, you'll know that oil paint takes a long time to dry. Even thin paint, which dries a lot faster than thick layers of paint, can take a few days to dry.

Don't be afraid to let your painting dry for a past the paint feeling dry to the touch. Remember: When varnish mixes with wet paint, it can carry the pigment across the canvas, distorting the painting. So, always wait until your paint is completely dry.

From here, it's very much the same as above.

Remember: Always apply varnish in a well-ventilated room.

How to varnish an oil painting

• Pour your choice of varnish into a shallow bowl. I'm a huge fan of using small mason jars.
• Lay your painting, artwork up on a protective surface. Varnish likes to go everywhere varnish isn't welcome, but an old sheet, some newspaper, or a spare towel will help protect your workspace.
• Dip your brush into the varnish.
• Sweep the varnish lightly across the painting. Work side-to-side, slightly overlapping with each stroke to ensure an even coat.
• Don't re-varnish an area that you've already varnished. Dragging wet varnish through partially dry varnish can produce a cloudy finish.
• Apply an additional layer of varnish once the varnish is dry.
• Allow the varnish to dry completely.

Enjoy your freshly preserved varnished painting!