Varnishing Paintings: Why, and How?

Is there any one art material that causes painters more grief than varnish? Varnishing oil and acrylic paintings is at best a tricky and often misunderstood process. This is because many artists consider it the final and permanent step to painting, which could alter the final result of the work if not done properly. In fact, proper varnish is made to be a removable layer to safeguard your work against the elements. No need to be afraid! Let’s discuss.

Why varnish your painting?

Most art conservators and materials manufacturers agree that varnishing oil or acrylic paintings serves two main purposes:

  1. to protect the surface of the finished work from UV rays, dust, and other contaminants, and
  2. to unify the surface of the work to an even gloss, satin, or matte finish.

As mentioned earlier, the main misconception about varnish is that it is a permanent final layer. In actuality, varnish is meant to be totally removable from your painting. It is employed to take the assault from atmospheric elements, dust, UV rays, and any other environmental factors while your original painting remains untouched underneath. If over time the varnish yellows, cracks, or loses clarity, it can be removed and reapplied. Though the actual process of removing varnish is much more in-depth, you can think of varnish like a pane of glass, protecting your artwork from the elements. In this way, it makes your artwork more archival.

So how do you apply varnish?

Firstly, varnish should not be applied to a painting until it is fully dry. When is that? It depends. This is one of the tricky aspects of varnishing. For oil paintings, most experts agree that you should wait anywhere between 3 to 12 months for the paint to fully oxidize. This of course also depends on the thickness of your paint. For acrylics, your work needs to be fully cured, though this is not as much of a waiting period. Again depending on the thickness of the paint, you should wait anywhere from a week to a month. When in doubt, play it safe: overestimate!

For acrylic paintings, it is recommended to apply an “isolation coat” between the finished painting and the varnish. This consists of a coat of clear acrylic medium evenly applied over the entire surface. The purpose of the isolation coat is to protect the acrylic painting underneath from chemicals which may later be used to remove varnish. While oil paintings naturally are not threatened by chemicals used to remove their varnishes, acrylic paintings can be. The isolation coat is used as a buffer to lessen the threat to the artwork.

When varnishing for the first time, using a new varnish, or varnishing a surface you’re not familiar with, it never hurts to run a test. You can even test out different types of varnish on a test painting of similar colour and texture to view the results before applying it to the actual work.

Varnishing paintings with a brush

The most thorough and practical tips and suggestions I have found are written by David Pyle and posted on the Windsor and Newton website:

1) Use a 1”- 4” flat wide, soft, tightly packed, varnishing brush (such as the Winsor & Newton Monarch glazing/varnishing brush).  Keep it clean and use it only for varnishing.

2) Place the work to be varnished flat on a table – do not varnish vertically.

3) Apply the varnish in 1-3 thin coats, rather than 1 thick coat. A thick coat will take longer to dry, may dry cloudy, drip or sag during application and has a greater chance of showing brush strokes when dry.

4) Thinned varnish is more susceptible to producing bubbles. Do not be vigorous in your application.

5) Apply in long even strokes to cover the surface top to bottom while moving from one side to the other. While working, inspect the varnish layer at all angles for bubbles. Even them out immediately.

6) Once you leave an area, do not go back over areas that you have done. If you do, you risk dragging partially dry resin into wet, which will dry cloudy over dark colors. If any areas were missed, allow to dry completely and re-varnish.

7) After varnishing, we recommend that the surface should be shielded from dust with a protective plastic film “tent”.

8) For a matte surface, apply the first layer(s) using gloss varnish.  Because multiple layers of matte varnish will cloud, only the final layer should consist of the Matte varnish.

Varnishing paintings with spray varnish

As well as the traditional varnishes applied with brush technique, many manufacturers now offer spray varnishes. Spray varnishes allow you to apply extremely thin coats, lessening the chances of brushstrokes, clouding, or an uneven surface. A few tips for using spray varnishes:

  1. Safety first! Always varnish in a completely ventilated area. This means that you have to have airflow between two different sources. You should also wear a respiratory mask to protect yourself from breathing in the chemicals.
  2. Hold your spray varnish about one foot from your painting, and sweep in an even manner back and forth, creating a thin coat.
  3. Wait between coats as per the manufacturer’s instructions (usually 15 – 30 minutes).
  4. Leave your varnish to fully dry before handling.

OK, so how do you remove varnish?

I won’t lie: varnish removal is not the easiest task. It is however a necessary process in keeping your painting archival through decades of environmental abuse. How you remove varnish depends on which varnish you choose, and each reputable manufacturer will supply you with specific instructions for successful removal. In general terms, removing a varnish involves using a specific chemical (ammonia, acetone, or other specialized products that manufacturers produce to sell alongside their varnish). Because manufacturers and products can differ wildly, it is best to follow the specific instructions provided. Depending on the value or concern you have for the artwork, it is also always an option to hire a professional art conservator to expertly remove and reapply your varnish.

You’ve convinced me. Now what varnish do I choose?

If you care about the longevity and archival qualities of your work, you should use a high-quality removable varnish. Remember, manufacturers who produce high quality products also provide ample literature and information for you about their product, as well as how to apply it and how to remove it. Have a look at some recommendations for quality varnishes below, then go forth and varnish your paintings.

Windsor & Newton

Gamblin Artist Colors

Golden Artist Colors

Responses to “Varnishing Paintings: Why, and How?”

  1. Eileen Johnston

    I need help! I have varnished three 72″h.x15″w. panels with MSA Varnish with UVLS (high gloss). The acrylic paint was dry on the panels. I used a soft wide brush, laid them down flat and proceeded to brush from the left to the right going across, because going lenght wise, would be hard to continue the brush stroke. The varnish seemed thick, but I worked to get it on evenly and after it dried, 10 hours later in the light of day, I could see an uneven finish with high sheen areas, low, and spotty looking areas. Looking at the painting from 10′ out, you don’t see colors, but just a shiny surface. First, to rid myself of the uneveness, my husband wants me to go over it again with the high gloss varnish (to try to even it out) and then do a final matte varnish last. Does this make sense to you? And will the matte finish over the high gloss take the shine down? (which is what I want). Thank you in Maryland

    1. thepracticalartworld

      Dear Eileen,
      It’s hard for me to say as I’m not sure what product you are using exactly. If you were going for a satin finish, is there a reason you used a high-gloss varnish? I believe if you put a coat of matte varnish over the gloss, it would just appear matte.

      I’m not sure if the problem that the vanish is causing you is from the application or the material itself. Is it a varnish that needs to be thinned with solvent first?

      Because it’s difficult for me to guess, I would recommend checking out Golden’s MSA varnish info page. It’s FULL of way more information than one human being could give you! Hopefully if you read through you will be able to pin point what the problem is and hopefully resolve it and complete your paintings.

      Golden’s MSA Varnish information: http://www.goldenpaints.com/technicaldata/msavar.php#app

  2. clivepatterson

    An additional use for matte varnish that I use is seal the surface a white picture mount around a finished painting if you do not want to display your picture under glass.
    Use a double thick mount board to keep it flat with painted surface and use 2 coats of a spray matte varnish ( conservation grade if possible) being sure to apply an even coat on both applications. Often it takes a little long to dry than on an acrylic painted surface.
    The result resists normal finger marks and can usually stand up to handling in galleries but is not foolproof!

  3. dennis marshall

    What is the difference from a woodworkers varnish and the varnish sold by art stores?

  4. tigger

    Does anyone have any tips on a good retouching varnish? I recently tried out one from Winsor Newtons and found it to be too glossy for my purposes. It makes the surface of the painting very light/glare sensitive. Best would be a retouching varnish that made the color pop like a wet painting but without gloss finish (I suppose this would be a matt finish). Blick art materials has a list of retouching varnishes: http://www.dickblick.com/categories/varnishes/#retouchingvarnishes. If anyone uses any of these, or any other varnish not on this list, perhaps they could give a short review and description?

    thanks in advance and glad to have found this discussion.

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  11. Steve

    Sooo…wish I’d read this before varnishing! I used Atelier Satin varnish, but didn’t apply an isolation layer. It was a think coat and I am going to apply one more. There is no cloudiness so far. It seems completely clear. Are there any dire consequences?

  12. thepracticalartworld

    Hi Steve, I’m not familiar with Atelier but I looked on their website and it sounds like it’s a non-removable varnish. The isolation layer is meant to protect the painting in the event that you try to remove varnish, and their website also says you don’t necessarily need one… so hopefully you won’t have any problems.

  13. Tom McLean

    I want to varnish an oil-drip painting with a product that will tone down the too-bright whites and yellows.. Any suggestions?

  14. aloysgambietzr3

    I doubt it! Varnishing oil and acrylic paintings is at best a tricky and often … ocanvasn.wordpress.com

  15. Dawn Connelly

    I varnished some paper mache artwork with a marine varnish which made the pieces look glaring and cheap. I went to my local hardware store to buy some matte varnish with the hopes of toning down (a lot) the gloss but the only varnish I could find that was matte suggested sanding the work first. Clearly I can’t do that to paper mache art sculptures. I don’t know how to proceed. Am beside myself because I have sold one of the pieces and they don’t expect a mirror when they look at the sculpture. I live in Guatemala and don’t have access to art stores nor the money to ship from USA. Do you think it would be OK to apply a basic matte finish varnish or am I screwed?

  16. Gloria L

    Dawn, since you’ve already used a hardware store varnish, see if you can locate some of the excellent (for art) Patricia Nimocks’s “Clear Acrylic Sealer” Matte by Plaid. It can even be sprayed over oil based paints, etc. It was made for hobbyists but I have used it on my serious drawings and in renewing surfaces for oil paintings. Krylon by Sherwin Williams also makes a matte spray clear coat.

  17. Ann

    I have just put a matte varnish on a large dark painting and the result is very cloudy. Can I apply a satin coat to improve the color depth?

  18. Anita

    I have had success in doing this. I had a large acrylic on panel painting with a lot of black in the background; after using the satin varnish it was cloudy in some area over the black. I was heartsick as the painting was already sold and I was merely varnishing it. I decided to give applying gloss of the matte a try and it worked wonderfully!

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    Hi to every one, it’s really a nice for me to visit this web page, it contains helpful Information.

  20. Helen Field

    Reblogged this on A slurp of words and commented:
    Helpful information, can’t wait to try my new spray varnish!

  21. verbalthevillian

    Hi everyone! Great tutorial on varnishing gave me great insight into doing properly for once. One thing I am worried about is that daunting fear of too much light sensitivity/ glare on the finished product. If I am using all Holstein brand products (http://www.holbein.co.jp/en.html) has anyone here used their varnishes or crystal glazes yet? Or alternatively is there any suggestions to help avoid over glare or over-sheen? I find there’s nothing worse than varnishing a piece and then it looks awful in the daylight or over-glare due to certain lights in people’s homes. This may have just been an issue of doing it incorrectly in the past on my part but I’m curious other’s experiences on the subject of over-glare and light sensitivity after varnishing. Ideally I don’t want it to be matte and enjoy a crystal look but as with Dawn often if done incorrectly it looks cheap. Thoughts anyone?

  22. verbalthevillian

    ***correction its HOLBEIN, not Holstein as I had previously typed.

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  24. Christa Kumar

    Please help: I varnished with Golden Polymer Varnish my (Golden)acrylic painting just once, before applying an isolation coat. Can I
    go over the slightly varnished painting with Golden Isolation Coat, let it dry, and then varnish it again with Golden Polymer Varnish?
    Please reply.

  25. Nelson Hernandez

    Good day,
    I need your help. To protect a work of art that I acquired. Purchased a jar of Grumbacker Gloss Medium & Varnish (Acrylic). It turned out that the final work was very Glossy.

    Any suggestion can be give in order to lower the current degree of brightness a little.


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