How To Varnish An Acrylic Painting

Hey guys!

So we’re starting to near the end in our first Paint With Me series, and I thought now might be a good time to write a little tutorial about how I varnish my acrylic paintings, so if those of you that are doing the painting want to varnish it as well, you’ll know how!

Varnishing is the act of putting a final layer over a finished painting, sealing the painting and giving it it’s final look.  There are a few reasons why varnishing is a good idea:

  • It protects your painting from dust, dirt  and UV light
  • It allows the painting to be gently wiped with a moist cloth when needed for cleaning/dusting reasons
  • It adds an extra element of dimension to the painting (colours look deeper when viewed through varnish)
  • It adds extra vibrancy to your paint colours (it makes the colours a bit more saturated and more vibrant)
  • It pulls together your finishes for a professional-looking finish (using gel mediums, glazing mediums and other mediums with your paint creates patches here and there of varying glossiness.)  A layer of varnish unifies the finishes to one overall finish, making the entire painting look cohesive and eliminating any patchiness.

My Varnishing Method

Step 1: Isolation Coat

The very first thing I do with a finished painting is let it sit. Let it sit for a good one to two weeks depending on the mediums you’ve used in the painting and how thick you’ve applied the paint (if you have used very heavy impasto-like layers or if you have used anything like the Golden OPEN mediums, you will most likely have to wait longer as these materials take much longer to finally cure).  I make sure I give my painting enough time to fully cure before even thinking about varnishing it.

So after it’s completely cured and I want to varnish it, the first thing I do is put on what’s called an isolation coat. This is simply a layer of medium to separate your paint from the varnish itself. I usually use self-leveling clear gel because I like that it has self-leveling qualities to it, so I know that brush marks will not show. Something like soft gel would also work.  I always use a gloss finish for this step, because anything that has matte finish to it has the chance to turn milky. So regardless of what kind of varnish you want to use, I would always use a gloss finish for the isolation coat.

The clear gel may fog up a bit while you’re applying it, but this is normal.  Don’t freak out if you see it turning foggy or milky, just make sure you’ve got it on nice, even, smooth, with no missed spots, and let it be. It will clear up on it’s own while it goes through it’s drying/curing process. You can also thin it with a bit of water, which will lessen the cloudiness and make it easier to spread out.

So I just cover my entire painting with a nice layer of self-leveling clear gel, making sure it is spread smoothly and evenly over the painting, and left somewhere flat,level, and free of dust and dirt to dry (I usually leave it sitting on a table in my art room, and keep my door closed so a certain little four-legged furball doesn’t decide to pay my wet painting a visit).

Step 2: The Waiting Game

Once you’ve got your isolation coat finished, you have to let your painting sit some more.  After a day or two the painting will seem dry, but it is not cured at this point.  We want to make sure the isolation coat is fully cured before putting on the varnish, so let your painting sit for about a week. It will already be looking pretty good at this point because the clear gel has unified the finish of your painting.  But it gets even better when we put on that varnish!  So be patient and know that good things are coming 🙂

Once the isolation coat is dry, it doesn’t have to be laying flat anymore.  If you want to have it leaning up against a wall for the rest of the week, that’s fine.  A word of warning, though: when the painting is covered in this gel, even when the gel is cured, it will have a soft feel to it.  Do not let any other painting touch this painting, as it might stick to the other painting, and both will be damaged when you try to pull them apart.  Keep your painting on it’s own with nothing touching it. Freshly isolated and freshly varnished paintings are at their most susceptibility to damage, so be gentle  and protective with them 🙂

Step 3: Varnish!

So now that our painting has had a good week or more to fully cure, we can finally get to the varnishing!

This is the varnish that I use. It is Polymer Varnish with UVLS by Golden. The UVLS protect the painting from UV light fading and damage. I use a gloss finish for my acrylic paintings. This varnish needs to be thinned out in a ration of 4:1, so I use an empty gel medium container to mix the varnish with water in the appropriate proportions.

If your varnish needs to be thinned out, do this now and give it a good stir so it is ready to go.  Give your painting a little wipe with a microfiber or other dust-grabbing soft cloth and lay it out flat. Use a flat, soft brush for your varnish, and keep the same brush for varnishing purposes only. Make sure the brush is high quality and will not lose any hairs while you are varnishing.

The technique of varnishing is pretty simple, just dip the tip of your brush into the varnish (no more than 1/2 the length of the bristles should be covered) and gently glide the brush starting at the top of the painting across the painting horizontally.  Once you have finished that stroke, dip your brush again (always wiping off the excess on the lip of the container) and start from the same side, gliding across horizontally again. You should be able to see where you have varnished and where you haven’t.

As you can see here by the white arrows, the line where I have varnished and where I have yet to varnish is clearly shown in this lighting. Also, if you look at the light reflections by the pink arrows, you can see how much more glass-like the wet varnish looks when compared to the dry clear gel finish.

As you can see here by the white arrows, the line where I have varnished and where I have yet to varnish is clearly shown in this lighting. Also, if you look at the light reflections by the pink arrows, you can see how much more glass-like the wet varnish looks when compared to the dry clear gel finish.

Continue until the entire face of the canvas has been covered, then go around and varnish the sides.  I then come back to the face of the canvas and repeat the process starting from the other side and working vertically.  When that is finished I look over the painting, watching for any pools of varnish that have formed.  If there are any, I gently glide my brush across the painting either horizontally or vertically to spread out the varnish, and then wipe my brush to get rid of whatever extra has been picked up.  You want to make sure you have a smooth, even coverage with no bare spots and no pools.  But do not overwork the varnish.  Use as few strokes as possible, and then let it sit undisturbed.

The freshly varnished painting is now left to sit and dry!

The freshly varnished painting is now left to sit and dry!

NOTE*** If you come to check on your painting while the varnish is drying and notice that you missed a spot, do not try to fix it! Just let it dry and cure, and then apply a second coat of varnish to cover any patchy spots you missed.

So now that our painting is varnished, we just have to let it sit! Let it sit flat for 2-3 days to make sure the varnish is dry, and they let it sit for a week or two (can be upright at this point if you want) to let it fully cure before hanging it on a wall or giving it to someone.  Remember to never store paintings face-to-face, and while the varnish is curing it will be susceptible to damage, so keep it from touching anything else while it cures.  Once the varnish is fully cured it will have a hard finish, protecting your painting from dirt and light!

So that’s it! Thanks for reading, and till next time, keep creating!


Leave a Comment :)

  1. Hello, when you talk about mixing 4:1 for Gloss Varnish. Which combo is it? 4 gloss and 1 Water, or the other way around. Thanks for your help and all the info on your site.

    • Hello Greg! Yes it’s 4 parts varnish to 1 part water. You just want to thin it out a little bit. The ratio is on the bottle as well, so no worries. Thanks for your comment, I’m glad my site is helpful!