The Ultimate Guide to Varnishing Paintings: Types, Top Varnish Recommendations, Techniques, and Varnish Removal

Varnishing is a crucial final step in the painting process, especially for oil and acrylic artworks. It not only enhances the visual quality of a piece but also provides a protective layer against dust, UV rays, and environmental pollutants. This article explores the different types of varnishes, application techniques, and how to safely remove varnish when necessary.

A Guide to Varnishing Paintings

• Why Varnish a Painting?

• Types of Varnish

• Choosing the Right Varnish Finish

• Top Varnish Recommendations

• When to Varnish

• How to Apply Varnish

• How to Remove Varnish

• Conclusion

Oil painting

Why Varnish a Painting?

• Protection: Varnish creates a barrier that shields the painting from dust, grime, moisture, and physical abrasion.

  UV Protection: Many modern varnishes include UV inhibitors that prevent color fading from sunlight exposure.

  Surface Unification: Varnish evens out the finish across the painting, eliminating patchy areas of gloss or matte.

  Color Enhancement: Varnishing deepens and enriches the colors, making them appear more vibrant and saturated.

Types of Varnish

Varnishes vary in appearance, drying time, and solubility. They fall into two main categories: removable (final varnishes) and non-removable (permanent varnishes).

1. Natural Varnishes

Dammar Varnish

• Made from: Dammar resin and turpentine.

• Finish: Glossy, traditional appearance.

• Used for: Oil paintings.

• Pros: Time-tested; enhances depth and color.

• Cons: Yellows over time; not ideal for conservation.

• Removal: Soluble in turpentine or mineral spirits.

Mastic Varnish

• Made from: Mastic resin in turpentine.

• Finish: Glossy but more flexible than dammar.

• Used for: Traditional oil painting; often avoided in modern practice.

• Cons: Prone to cracking and yellowing.

• Removal: Soluble in turpentine.

  Note: Natural varnishes are less favored today due to their aging characteristics and brittleness.

2. Synthetic Varnishes

Acrylic Varn4ishes (e.g., Golden MSA, Liquitex)

• Made from: Acrylic resin in mineral spirits or water.

• Finish: Available in gloss, satin, and matte.

• Used for: Acrylic and oil paintings.

• Pros: Clear, non-yellowing, flexible; UV protection.

• Removal: Soluble in specific mineral spirits or custom solvents (check manufacturer’s guidelines).

Alkyd Varnishes

• Made from: Modified synthetic resin.

• Finish: Usually glossy.

• Used for: Oil paintings.

• Pros: Fast-drying and durable.

• Cons: Not always removable; not as widely used as acrylics.

• Removal: Requires manufacturer-recommended solvent.

Ketone Resin Varnish (e.g., Regalrez, Laropal A81)

• Made from: Stable synthetic resin.

• Used in: Conservation practices.

• Pros: Stable, non-yellowing, reversible.

• Removal: Soluble in low-aromatic solvents.

Choosing the Right Varnish Finish

• Gloss: Maximizes color depth and contrast; shows surface flaws.

  Satin: A compromise between gloss and matte; reduces glare.

  Matte: Minimizes reflection but may dull colors.

  Some varnishes can be mixed to create a custom finish, or a gloss varnish can be overcoated with a matte layer.

Top Varnish Recommendations

Gamblin Gamvar

Type: Synthetic resin.

Finish: Available in gloss, satin, and matte.

Features: Gamvar is popular for its clarity, ease of removal, and versatility. It can be applied when the painting is touch-dry.

Application: Brush-on varnish that requires careful application to avoid bubbles.

Pros: Non-yellowing, easy to remove, enhances colors.

Cons: Requires careful application to prevent streaks.

Winsor & Newton Dammar Varnish

Type: Natural resin.

Finish: High gloss.

Features: Traditional damar varnish known for its deep, glossy finish.

Application: Best applied in thin layers with a soft brush.

Pros: Enhances color depth, easy to remove.

Cons: Can yellow and crack over time.

Golden MSA Varnish

Type: Synthetic resin.

Finish: Available in gloss, satin, and matte.

Features: UV resistant, flexible, and durable. It can be thinned with mineral spirits for easier application.

Application: Suitable for both brush and spray applications.

Pros: UV resistant, flexible, and provides a protective barrier.

Cons: Requires mineral spirits for thinning and removal.

Krylon Gallery Series Conservation Varnish

Type: Synthetic resin.

Finish: Available in gloss, satin, and matte.

Features: Provides UV protection and is easy to apply with a spray can.

Application: Spray application offers an even coat with minimal effort.

Pros: Convenient spray application, UV protection.

Cons: Less control over application compared to brush-on varnishes.

When to Varnish

• Oil Paintings: Wait 6 months to 1 year for full curing. Alternatively, apply a retouch varnish after a few weeks to protect the surface until final varnishing.

  Acrylic Paintings: Drying takes 1–2 weeks; however, manufacturers recommend waiting 1–2 months before applying a final varnish.

How to Apply Varnish

Supplies Needed

• Varnish of choice (check if it’s removable or permanent)

• Clean, soft varnishing brush or spray equipment

• Dust-free workspace

• Gloves and mask (especially for solvent-based varnishes)

Preparation

1. Ensure the painting is fully dry.

2. Clean surface gently with a soft brush or cloth.

3. Test varnish on a corner or a separate painting first.

4. Place painting flat and horizontal.

Application Methods

Brush Varnishing

• Use a wide, soft, high-quality varnish brush.

• Work quickly and evenly across the surface.

• Avoid overworking; streaks can form.

• Allow drying between coats if applying multiple layers.

Spray Varnishing

• Suitable for even, streak-free coverage.

• Use a spray can or airbrush setup.

• Apply thin, sweeping strokes from a distance of 10–12 inches.

• Multiple light coats are better than one heavy coat.

How to Remove Varnish

Removing varnish should only be done, when necessary, such as for cleaning, restoration, or re-varnishing. Always test solvents first, and consult a conservator if unsure.

General Steps for Removing Varnish

1. Identify the type of varnish: Know whether it’s dammar, acrylic, or synthetic.

2. Select the correct solvent:

   • Dammar or mastic: use turpentine or mineral spirits.

   • Acrylic: use manufacturer-recommended solvent (often mineral spirits or proprietary removers).

   • Conservation-grade (e.g., Regalrez): removable with specific aliphatic hydrocarbons.

3. Test on a small area: Use a cotton swab to test the solvent.

4. Remove gently: Roll a swab soaked in solvent across the surface, lifting the varnish. Avoid scrubbing.

5. Work in small sections: Always ventilate the workspace and wear protective gear.

6. Neutralize: If recommended, wipe with a clean swab dampened with distilled water or a neutralizing agent.

7. Let dry fully: Allow the painting to air out before reapplying new varnish.

   Warning: Over-cleaning or using the wrong solvent can damage the paint layer. When in doubt, consult a professional conservator.

Don't use Polyurethane Varnishes

Polyurethane varnishes are not a traditional artist's varnish. Used mostly for wood, furniture, and commercial surfaces, not typically recommended for fine art paintings, especially oil or acrylic works.  Polyurethane is synthetic and not reversible like conservation-grade varnishes. Removing polyurethane varnish from an oil painting is a delicate process and must be done with extreme caution to avoid damaging the paint layers beneath.

Here's how you might approach it:

Important Warnings

• If the painting is valuable or sentimental, consult a professional conservator.

• Always test any solvent in a small, inconspicuous area first.

• Use good ventilation, gloves, and eye protection.

Step-by-Step Guide

1. Identify the varnish

Make sure it's polyurethane. Polyurethane is very durable, usually glossy, and has a plastic-like hardness. If unsure, a conservator or lab can help identify it precisely.

2. Gather materials

• Cotton swabs or soft cloth

• Mineral spirits (odorless preferred)

• Isopropyl alcohol (91% or higher)

• Acetone or lacquer thinner (very strong, use with extreme care)

• Gloves and mask

• A magnifying glass or loupe

• Soft brush or sponge

• Ventilated workspace

3. Start with the mildest solvent

Try odorless mineral spirits:

• Dip a swab, dab it gently on a small area.

• Watch closely—if the varnish softens or gets sticky, carefully remove it by rolling the swab.

• If the paint comes off too—stop immediately.

If mineral spirits don’t work, try isopropyl alcohol, sparingly. Alcohol is more aggressive and might affect the paint if there are medium-rich layers or glazing.

4. Only if absolutely necessary: acetone or lacquer thinner

These will likely remove the varnish—but they can also damage the oil paint.

• Use with extreme caution, and again, only after testing a tiny area.

5. Work slowly and in sections

Never flood the surface. Use a fresh swab for each area. Be patient—it may take hours or days depending on size and thickness.

6. After varnish removal

Once the polyurethane is off:

• Let the painting rest for at least a week to allow any residual solvent to evaporate.

• Re-varnish using a conservation-grade varnish (like Gamvar or Regalrez) if desired.

Would you like to help choose a good conservation varnish or match the finish to your painting? Or, are you trying to remove polyurethane from your own work or a piece you acquired?

Conclusion

Varnishing is both an art and a science. It enhances your painting’s appearance and extends its life. Understanding the types of varnishes and how to apply or remove them gives you greater control over the longevity and presentation of your work. Whether you prefer a high-gloss finish or a subtle matte sheen, the right varnish can be the final touch that completes your painting.