Maybe you have a painting that you thought was finished, and you applied a coat of varnish. Then, you discover that you forgot to sign it, or you’re not satisfied with one area of the painting.
What do you do? Can you paint over varnished canvas to repair your painting? Well, the answer is ”it depends.”
If you applied an acrylic, water-based varnish, or sealing medium, you can paint over it. If it’s a glossy varnish, I recommend sanding it lightly to remove the shiny surface. Then just paint with your acrylics over the varnish.
But, if the painting has a coat of mineral-based varnish, rather than acrylic-based, then you have to remove it before painting.
Why Do Paintings Have a Varnished Top Coat?
Artists apply varnishes over acrylic and oil paintings for a durable finish without yellowing. They provide a barrier that protects the surface from dust and dirt and diffuses ultraviolet rays.
Most of today’s varnishes are also flexible, so the paint doesn’t crack or chip with changes in temperature.
Can You Paint over Varnished Canvas?
Painting over a varnished canvas is possible, but it depends on the type of varnish used.
You shouldn’t try painting over archival and mineral-based varnishes. The paint won’t hold up on those surfaces.
When painting over archival varnish, the paint often puckers, cracks, remains tacky, and even slides off the painting.
On the other hand, if your painting has a coat of acrylic, water-based varnish, or gel medium, you can paint the entire surface over again, if you want to.
Since acrylic varnishes mix with acrylics to create texture or keep the paint wet, it’s suitable for painting over it when it’s dry. Just paint the area you want to change and apply another coat of acrylic varnish when the repair dries.
If you’re not sure what type of varnish your painting has, consult an art conservator at your local art museum. The conservator will offer advice regarding the varnish on your painting. Ask questions about how to remove dust and dirt, and how to remove varnish and repair damage.
How Do I Paint over an Archival Varnish?
If you have a painting that needs a little touch-up, but it has a coat of archival varnish, you shouldn’t paint over it. This applies to acrylic and oil paintings.
The problem is that the purpose of the archival varnish is to give the painting a permanent, protective barrier. If you paint over it with oils or acrylics, the paint will eventually rub off over time.
If I have a painting that I want to alter, I always remove the archival varnish before repainting the trouble spots.
How Do I Remove Varnish from a Painting?
If you have an acrylic painting sealed with archival varnish, you can remove the varnish coat before repainting.
Before you begin, make sure you’re in a well-ventilated area because you’ll be working with solvents. It’s also a good idea to wear gloves and protective glasses.
If this is your first time removing varnish from a painting, work on a practice piece that has the same type of paint as the one you want to repair. You want to ensure that the solvent won’t damage your artwork.
Here are the supplies you need to remove varnish from your painting:
- Soft cloths
- Pure mineral spirits
- Solvent tray
- Plastic sheets
- Protective gloves
- Eye protection
Steps to remove varnish:
1. Begin by pouring the mineral spirits into a solvent tray. Then, saturate a soft cloth with the solvent. Squeeze out the excess.
2. Lay the cloth out flat over the painting’s surface. Gently press out any wrinkles.
3. Place a piece of plastic over the cloth. This stops the solvent from evaporating. It can take up to 5 minutes for the solvent to start working.
4. Lift a corner of the cloth. If it feels tacky, then the solvent is working but hasn’t liquified the varnish yet. Check again after a few more minutes.
5. Rub your finger on the varnish. It’s liquefied when it’s not sticky.
6. Remove the cloth and replace it with another cloth, following the same procedure. Don’t try to rub off the varnish, or it could damage your painting.
7. Lift off the second cloth. Most of the liquified varnish should lift off with it.
8. Gently wipe off the rest of the wet varnish with a cloth.
If you see any of the paint on the cloth, stop removing the varnish because you’ll damage your artwork. Consult the varnish manufacturer or a professional artist for more information on removing varnish from your artwork.
Do I Have to Varnish My Painting?
Acrylic paintings don’t require varnishing, since acrylic varnishes have the same solubilities as the paint. If you want to remove the varnish in the future, the solvents used can also harm the acrylic painting underneath. So, I would seriously consider whether to apply varnish to acrylic or not.
Most professional artists apply archival varnish to their oil paintings. Oil paintings that don’t have a coat of varnish collect dirt in the paint textures. It’s difficult to remove the dirt without harming the paint.
An alternative to varnishing your oil painting is to display it behind non-reflective glass. The glass framing protects the oils from UV rays, dust, dirt, and the environment.
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Joseph Colella is a frustrated artist with over 40 years experience making art (who moonlights as a certified Business Analyst with over 20 years of experience in tech). While he holds a Diploma in Information Technology, in true wasted talent style he spent years trying to get into various Art degrees from the Accademia di Belle Arti (Napoli), and failed to get into the Bachelor of Arts (Fine Arts) at the University of Western Sydney. His goal is to attend the Julian Ashton School of Art at The Rocks Sydney when he retires from full time work. In his spare time, he writes for the this blog, WastedTalentInc, where he shares practical advice on art, making art, and art materials. Joseph’s art has been sold to collectors all over the world from the USA, Europe and Australasia. He is a trusted source for reliable art and copyright/fair use advice and is committed to helping his readers make informed decisions about making them a better artist.
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