Quick answer: How to use turpentine in oil painting comes down to three jobs: thinning paint for the first lean layers, mixing with oils and resins to make painting mediums, and cleaning brushes. Use only artist-grade, distilled or rectified turpentine, keep it to the early stages of a painting (thin layers first, oily layers later, following the fat-over-lean rule), work in a ventilated room, and store it in a sealed metal or glass container away from light. It is more toxic and flammable than odorless mineral spirits, so many painters reserve it for dissolving resin and use a milder solvent day to day.
Learning how to use turpentine in oil painting means learning two things at once: what the solvent does to paint, and how to handle a substance that is both a fire hazard and a respiratory irritant. Painters used it for centuries without alternatives. Today there are gentler options, which changes the question from “how do I use turpentine” to “when is turpentine the right choice and how do I use it safely when it is.”
This how-to covers the solvent itself, the right grade to buy, step-by-step use for thinning, medium-making, and cleaning, the fat-over-lean rule that governs where turpentine belongs in a painting, safety and disposal, and the alternatives. Oil’s reliance on solvents is one of the main practical differences from acrylic; the full comparison of oil and acrylic painting lays out the others.
What turpentine is
Turpentine is distilled from the resin of pine trees. The result, gum turpentine or spirits of turpentine, is a clear, strong-smelling liquid that dissolves oils, natural resins, and waxes. In oil painting it has three properties that matter:
- Solvent strength. It dissolves linseed oil, damar, mastic, and other traditional resins readily, which is why it has long been the solvent in classical painting mediums.
- Evaporation rate. It evaporates at a moderate speed, slower than acetone but faster than most odorless mineral spirits, leaving paint to dry by oxidation once it has gone.
- Residue. Pure, fresh turpentine evaporates almost completely. Old or impure turpentine oxidizes into a sticky, yellowing gum that can remain in the paint film.
Two grades matter for painters. Artist-grade (distilled, rectified, or double-rectified) turpentine has been purified to remove impurities and is the only type that belongs in paint. Hardware-store turpentine is less refined, may contain more residue, and is intended for cleaning and industrial use. The price difference is real, and so is the quality difference.
Materials for using turpentine
- Artist-grade turpentine in its original sealed container
- A small metal or glass palette cup (dipper) that clips to the palette
- A glass jar with a tight lid for brush cleaning, ideally with a coil or screen at the bottom
- Linseed oil (or another drying oil) for making mediums
- Lint-free rags or paper towels
- A metal container with a lid for solvent-soaked rags
- Nitrile gloves
- Good ventilation: an open window with cross-draft, or an exhaust fan
Step by step: thinning paint with turpentine
Turpentine’s main painting job is to thin paint for the first stages: toning the canvas, sketching in the composition, and blocking in large areas with lean, fast-drying paint.
- Pour a small amount of turpentine into a palette cup. A tablespoon or two is enough for a session. Keep the main container closed.
- Put paint on the palette and pull a portion aside with the knife.
- Dip the brush into the turpentine, touch it to the rag to remove the excess, then work it into the paint. For a toning wash, the mix can be quite thin, like watercolor. For a drawing stage, aim for the consistency of ink or thin cream.
- Apply to the primed canvas. Turpentine-thinned paint dries matte and fast, often within a few hours to a day.
- Stop thinning with turpentine alone after the first layer or two. Paint thinned heavily with solvent and nothing else has a weakened binder; if built up in thick layers it can become brittle or chalky. From the block-in onward, thin with a medium that contains oil.
A useful rule of thumb: never thin paint with more than about one part turpentine to one part paint for anything other than an initial wash that will be covered.
Step by step: making a painting medium
Most traditional mediums are a mix of a drying oil, a solvent, and sometimes a resin. Turpentine is the solvent in the classical recipes because it dissolves resin where mineral spirits will not.
Basic lean medium
1 part linseed oil : 2 parts turpentine. For early layers. Thins paint, dries reasonably fast, keeps enough oil in the mix for a sound film.
Balanced medium
1 part linseed oil : 1 part turpentine. For the middle stages of a painting. Smooth handling, moderate gloss.
Classic resin medium
1 part stand oil or linseed oil : 1 part damar varnish : 1 part turpentine. Damar adds gloss, speeds setting, and gives glazes depth. Damar is itself resin dissolved in turpentine, so turpentine is unavoidable here; mineral spirits will not keep the resin in solution.
Mix small quantities in a labeled glass jar, shake, and decant a little into a palette cup for each session. Stand oil versions are slower-drying and more leveling; linseed versions are faster and brushier.
The fat-over-lean rule
Each layer should contain at least as much oil as the layer below. Turpentine-heavy (lean) mixes dry fast and shrink; oil-heavy (fat) mixes dry slowly and stay flexible. A fat layer under a lean one causes the top to crack as the bottom keeps moving. So turpentine use should decrease as the painting progresses:
| Stage | Medium | Approximate ratio (oil : turpentine) |
|---|---|---|
| Toning / underdrawing | Turpentine alone or nearly so | 0 : 1 to 1 : 4 |
| Block-in | Lean medium | 1 : 2 |
| Middle layers | Balanced medium | 1 : 1 |
| Final layers / glazes | Fat medium | 2 : 1 or oil alone |
| Varnish (after 6–12 months) | Resin varnish, thinned if needed with turpentine | n/a |
Step by step: cleaning brushes with turpentine
Turpentine dissolves wet oil paint completely, which makes it an effective brush cleaner, though its cost and fumes lead many painters to use odorless mineral spirits for this job and save turpentine for painting. If you do use it:
- Wipe as much paint as possible from the brush onto a rag.
- Swish the brush in a jar of turpentine, pressing gently against the coil or bottom. Do not jab, which splays bristles.
- Wipe on the rag. Repeat until the rag stays clean.
- Wash with brush soap or mild dish soap and lukewarm water to remove the solvent and any remaining pigment.
- Reshape and dry flat or bristles-down.
- Cover the jar. Let the pigment settle overnight; the clear solvent on top can be poured off and reused several times.
A faster alternative for session cleaning is to wipe the brush and then work it in a little linseed oil or baby oil before the soap stage. The oil lifts pigment without solvent at all.
Safety: handling turpentine properly
Turpentine is a skin irritant and sensitizer, its vapor irritates the eyes and respiratory tract and can cause headaches and dizziness in poorly ventilated rooms, and the liquid and rags soaked in it are flammable. Long-term exposure to solvent vapor is a recognized hazard for painters. The precautions are straightforward.
- Ventilate. Cross-ventilation with a window and a fan is the minimum. Never use turpentine in a closed room.
- Keep the container closed. Most vapor exposure comes from open jars, not from the paint. Decant small amounts and cap everything else.
- Use palette cups with lids and close them between uses.
- Wear nitrile gloves if your hands will be in contact with it, and never wash hands or skin with turpentine.
- Keep it off food surfaces and away from children and pets.
- Store rags safely. Rags soaked in oil and solvent can self-heat and ignite as the oil oxidizes. Lay them flat to dry outdoors or seal them in a metal can with water before disposal.
- No open flames or smoking in the studio.
- Store in the original or a metal container, cool and dark. Light and air degrade turpentine into a sticky, less effective form.
- Stop if you feel unwell. Headache, dizziness, or nausea means the room is not ventilated enough.
Pregnant painters, people with asthma or chemical sensitivities, and anyone painting in a shared living space have good reason to skip turpentine entirely in favor of the alternatives below.
Disposal
Never pour turpentine down a drain. Used solvent should sit in a closed jar until the pigment settles, then the clear part can be decanted and reused. The sludge at the bottom, and any solvent too dirty to reuse, goes to a household hazardous waste facility. Fully dried rags can usually go in household trash, but check local rules.
Alternatives to turpentine
| Solvent | Strength | Odor and toxicity | Dissolves damar? | Best for |
|---|---|---|---|---|
| Artist turpentine | High | Strong odor; irritant; sensitizer | Yes | Resin mediums; traditional recipes |
| Odorless mineral spirits (artist grade) | Moderate | Low odor; still a petroleum solvent, ventilate | No (poorly) | Everyday thinning; brush cleaning |
| Spike lavender oil | High | Strong floral odor; less irritating for many | Yes | Painters who want resin mediums without turpentine |
| Citrus-based solvents | Moderate | Citrus odor; can irritate skin | Partly | Cleaning; some thinning |
| Solvent-free (oil only) | None | None | n/a | Thinning with linseed or safflower oil; cleaning brushes with oil then soap |
| Water-mixable oils | n/a (water) | None | n/a | Painters who want oils with no solvent at all |
For most painters today the sensible arrangement is: odorless mineral spirits or no solvent for daily work, and turpentine reserved for making or thinning resin-based mediums and varnishes where nothing else does the job.
Common mistakes
- Using hardware-store turpentine in paint. Impurities can leave residue that yellows and weakens the film.
- Thinning every layer with turpentine. Underbound upper layers go chalky and can crack. Add oil as the painting progresses.
- Leaving jars open. The studio fills with vapor and the solvent degrades.
- Cleaning skin with it. Turpentine strips oils from skin and can cause dermatitis. Use soap, or oil followed by soap.
- Tossing solvent rags in a bin. Fire risk from oxidizing oil. Dry them flat or seal in water.
- Using old, cloudy turpentine. If it has thickened or smells rancid, it has oxidized. Dispose of it.
FAQs
What does turpentine do in oil painting?
It thins paint for early lean layers, dissolves resins to make traditional mediums and varnishes, and cleans brushes. It evaporates from the paint, leaving the oil to dry by oxidation.
How much turpentine should I mix with oil paint?
For an initial wash, paint can be thinned heavily. For working layers, keep turpentine to no more than about equal parts with paint, and move to a medium containing oil as the painting develops so later layers are fatter than earlier ones.
Is turpentine or mineral spirits better for oil painting?
Turpentine is stronger and dissolves natural resins; mineral spirits are milder, lower in odor, and sufficient for ordinary thinning and cleanup. Many painters use mineral spirits daily and turpentine only for resin mediums.
Is it safe to use turpentine indoors?
Only with real ventilation: an open window and a fan creating cross-draft, containers kept closed, and small quantities in use. In a sealed room it is not safe. People with respiratory conditions should consider alternatives.
Can I use turpentine to clean oil paint brushes?
Yes, followed by soap and water. Odorless mineral spirits, or oil followed by soap, do the same job with less odor and are what most painters use for routine cleaning.
How should I dispose of used turpentine?
Let pigment settle, reuse the clear solvent, and take the sludge and any unusable solvent to a hazardous waste collection point. Never pour it down the drain.
Final Thoughts
Turpentine does three things well: thins the first layers, dissolves resins for mediums, and cleans brushes. Used in small amounts, in a ventilated room, early in the painting and never as the only thinner all the way through, it remains a legitimate tool. For everything else, milder solvents or no solvent at all now do the job with fewer risks.
Solvent handling is one of the clearest dividing lines between oil and acrylic painting, and it weighs heavily in the choice between them. The guide to the differences between oil and acrylic painting puts this alongside drying time, color shift, surfaces, and cost so you can judge which medium fits your space and habits.
