Varnish Removal: How to Remove Artists’ Varnishes—Safely

Removing a varnish is a conservation task, not just a studio chore. It is, above all, a varnish removal problem that rewards careful testing and restraint. This article summarizes what major manufacturers say about their products, then lays out practical, conservative workflows you can use to test, soften, and lift common varnish types while minimizing risk to the paint. Where possible, I cite the maker’s own instructions and relevant conservation literature. When in doubt—especially with aged, sensitive, or valuable work—consult the manufacturer and a professional conservator.

Key principles for varnish removal before you start

• Identify the varnish (and whether it’s meant to be removable). Manufacturer data and SDS sheets are your first stop. Some modern “archival” sprays and mineral‑spirit acrylic (MSA) varnishes are designed to be removed; some permanent acrylic coatings are not (GOLDEN, 2025; Liquitex, 2025).
• Expect aged films to need “stronger” systems. Acrylic (meth)acrylate, synthetic low–molecular‑weight (LMW) hydrocarbon, and natural‑resin varnishes become more cross‑linked and polar with age; you may need blends, gels, or targeted systems rather than a single solvent wipe. (Baij et al., 2020; Phenix, 2023).
• Always isolate and test. If an isolation coat wasn’t used originally (this applies to isolation coats on acrylic paintings), proceed in tiny test areas and stop at the first sign of color transfer. (GOLDEN, 2025; Liquitex, 2025).
• Remember OMS vs. “true” mineral spirits. Odorless mineral spirits (OMS) like Gamsol have extremely low aromatic content, which lowers solvency compared with fuller‑aromatic “true” mineral spirits or Stoddard solvent. This often makes OMS gentler but less effective on tough, aged films. (Gamblin, 2025).

Popular removable picture varnishes and varnish removal methods

Scope: Brush and spray picture varnishes widely used by fine artists.

Why “OMS didn’t touch it” during varnish removal can be true.

Many commercial removable varnishes are based on low–molecular‑weight (LMW) hydrocarbon resins (for example, Regalrez systems such as Gamvar), while others use Paraloid B‑67–type resins or related acrylic resins. Fresh films from both classes often come off with mineral spirits; older films tend to need a bit more polarity (for example, adding isopropanol, or switching to higher‑aromatic mineral spirits), or completely different systems such as aqueous gels or microemulsions. (Gamblin, 2025; CAMEO, 2022; Baij et al., 2020; Chelazzi et al., 2023).

Odorless mineral spirits (OMS) are refined to strip out almost all aromatic hydrocarbons—the aggressive fraction that boosts solvency toward many picture‑varnish resins. With the aromatics removed, OMS is gentler but also less effective than “true” mineral spirits (such as Stoddard solvent), which retain a higher aromatic content and therefore dissolve or swell some aged varnish films more readily. In practice, an aged or cross‑linked varnish that does not respond to OMS may soften when you step up to a higher‑aromatic mineral spirits or to a carefully tested OMS blend that includes a small percentage of isopropanol. Always escalate in small, timed tests and watch for any color pickup. (Gamblin, 2025; Gamblin, 2015).

Safe, brand‑aligned varnish removal workflows

Always work with the painting in a horizontal position, with excellent ventilation, nitrile gloves, eye protection, and fire safety in mind. Document every step.

A. Mineral‑spirit acrylic (MSA) and other solventborne acrylic varnishes (varnish removal)

(Liquitex Soluvar; GOLDEN MSA; Krylon UV Archival; Old Holland ketone‑resin picture varnish; Daler‑Rowney Georgian)