Choosing the right thinner or solvent matters more than many painters realize: it affects paint handling, drying time, finish, and studio safety. After extensive research, hands-on testing, and consultation with professional artists and conservators, we’ve evaluated popular thinners, flow improvers, and solvent-free alternatives to recommend reliable options for acrylic and oil painters.
How we tested and chose
What we tested: We evaluated products across four practical categories: acrylic airbrush thinners, odorless mineral thinners for oils, traditional/alternative turpentine substitutes, and solvent-free/medium products. Each candidate was judged for: performance (thinning power, flow, and finish), drying behavior, compatibility with common paints (student & professional), safety/odor, and value.
Real-world use & expert input: Testing included airbrushing, hand-brushing, glaze/wash tests, and brush-cleaning effectiveness. We also gathered input from working oil and acrylic painters and reviewed Material Safety Data Sheets and manufacturer guidance.
Consumer feedback & durability: We reviewed user reports for long-term issues (yellowing, cracking, clogging) and looked for consistency across batches and container quality.
Final ranking considerations:
- Performance in intended use (airbrush vs. studio oil work) weighed most heavily.
- Health and safety (odorless/low-aromatic or solvent-free options) influenced recommendations for indoor/studio use.
- Value and brand reputation were considered alongside lab and hands-on observations.
Acrylic Airbrush Thinner
Compact and affordable, this acrylic thinner is formulated for airbrush use, easing flow without breaking paint binders. It’s great for fine-detail work, maintains flexibility, and is easy to measure—ideal for hobbyists and airbrush artists who need consistent results at a low price.
Why we picked it
Angelus 2-Thin is a no-frills, effective acrylic thinning solution tuned for airbrushing and small-scale work. In tests it produced smooth, even atomization with Angelus and other acrylic brands at the recommended 1:4 ratio; colors maintained flexibility after drying and didn’t show separation or flocculation.
Standout features:
- Optimized for airbrush use—consistent, predictable flow.
- Keeps paint flexible on leather, fabric, and canvas.
- Simple mixing ratio (1 part thinner to 4 parts paint) makes preparation quick.
Notes & limitations: Works best with water-based acrylics and is not a solvent for oil paints. If you primarily brush large canvases, you’ll want a different medium aimed at brushwork and glazing.
Winsor & Newton Liquin
A long-standing professional medium that speeds drying and improves flow for oil paints. Liquin halves drying time, enhances handling for glazes and thin layers, and resists yellowing—an excellent premium choice for studio oil painters seeking controlled, reliable results.
Why this is the premium pick
Winsor & Newton Liquin Original is a classic medium used by many professional oil painters. It significantly reduces drying time (touch dry in 1–6 days depending on film thickness), improves leveling, and produces a non-yellowing, durable film when used correctly.
Standout features & technical points:
- Speeds oxidation drying—sensible for layered techniques and faster turnaround.
- Improves flow and leveling, helping remove brushstroke drag in thin layers.
- Not a final varnish; formulated as a painting medium rather than a protective coat.
Notes & limitations: Because Liquin changes drying kinetics, test it with your palette to avoid overly fast skin formation in thicker passages. Use good ventilation and follow manufacturer recommendations.
Odorless Oil Thinner
A practical, odorless mineral thinner formulated for oil and alkyd paints. It thins heavy-bodied oils cleanly with slow evaporation and minimal residual odor—useful for indoor studios, classrooms, or artists sensitive to strong solvent smells.
Why it’s a great value
The 16.9 oz odorless paint thinner delivers broad compatibility with oil colors and alkyds at a price point that’s hard to beat. In studio thinning tests it softened stiff paints without introducing impurities and evaporated cleanly with little lingering odor—making it suitable for indoor use.
Standout features:
- Odorless formulation reduces irritation in small studios and classrooms.
- Slow, clean evaporation helps maintain workable open time for blending.
- Good container size for frequent users at a fair price.
Notes & limitations: Odorless mineral thinners are not entirely risk-free—observe standard solvent safety (ventilation, gloves). This product is a mineral spirit alternative rather than a solvent-free medium, so it will affect drying and film structure differently than linseed or alkyd mediums.
Gamblin Solvent-Free Gel
A solvent-free gel medium for oil painting that improves flow and handling without introducing traditional solvents. It’s a health-minded alternative that thickens or gels oils for glazing and brushwork while avoiding aromatic hydrocarbons.
Why editors picked it
Gamblin Solvent Free Gel Medium stands out because it directly addresses health and studio-safety concerns while still delivering excellent painting performance. In glazing and glazing-mulling tests it improved handling and gloss without the need for mineral spirits or turpentine.
Standout features & technical points:
- Solvent-free: reduces reliance on aromatic solvents for thinning and medium-building.
- Enables improved flow and modest gloss without compromising film integrity.
- Well-suited for studios where ventilation is limited or when solvent exposure is a concern.
Notes & limitations: This product is a medium rather than a traditional 'thinner'—it changes viscosity and surface qualities differently than mineral spirits. For brush cleaning or heavy-bodied reductions, you’ll still need an appropriate solvent or substitute.
Comparative overview — quick differences
- Acrylic Airbrush Thinner (Angelus) — Best for airbrush users and small-scale acrylic projects; lowest price and predictable thinning ratio.
- Winsor & Newton Liquin — Premium medium that accelerates drying and improves leveling for oil painters using layered techniques.
- Odorless Oil Thinner (16.9 oz) — Best value for most oil painters who want an odorless mineral thinner for indoor use and regular studio work.
- Gamblin Solvent-Free Gel — Editor’s pick for painters prioritizing health and solvent-free approaches while preserving professional-level handling.
Best overall: For broad studio use among oil painters, the odorless mineral thinner (Best Value) offers the best mix of performance, safety (lower odor), and price. Best for solvent-free users: Gamblin Solvent-Free Gel. Best for airbrushers on a budget: Angelus 2-Thin. Best premium pick for classical oil painting techniques: Winsor & Newton Liquin.
Final recommendation: If you paint oils in a shared or indoor studio and want the best balance of performance and cost, the odorless mineral thinner (Best Value) is the most practical choice. If your priority is reducing solvents altogether, choose the solvent-free gel (Editors Choice). Airbrush hobbyists will get the most immediate return from the Angelus thinner, while oil painters seeking faster drying and smoother glazing should consider Winsor & Newton Liquin. Our rankings reflect hands-on tests, product specifications, and user feedback—choose based on your medium (acrylic vs. oil), working method (airbrush, glazing, impasto), and studio-safety needs.