Quick answer: To oil out an oil painting, wait until the paint is touch-dry, then wipe the surface with a lint-free cloth to remove dust and apply a very thin, even film of a suitable medium, such as a refined linseed oil blend or a commercial oiling-out or retouching medium, to the dull, sunken-in areas. Rub it in thoroughly, then buff off almost all of it with a clean cloth. The goal is a barely-there film that restores depth to the colors before the next layer or varnish.
Anyone who wants to know how to oil out an oil painting has usually seen the problem first. A passage that glowed when wet dries to a flat, chalky patch, while the area beside it still looks rich. Painters call this “sinking in,” and it makes it hard to judge colors when you come back to work on a layer. Oiling out is the traditional fix: a thin film of oil or medium that briefly brings the surface back to how it looked wet.
This guide explains why paint sinks in, when oiling out helps and when it does not, how to do it step by step, which materials to choose and the mistakes that cause yellowing or tackiness. The technique is part of the craft of making durable oil paintings, the kind sold through galleries and shops; see the guide to oil paintings on canvas for sale if you are curious about how finished works are presented and priced.
What Is Oiling Out?
Oiling out is the application of a very thin layer of oil or oil-rich medium over a dry or touch-dry oil painting. It has two main purposes.
- Restore the wet look. Dull patches regain color depth and gloss, so you can see the painting more accurately.
- Improve adhesion between layers. A thin film of oil gives the next layer a slightly receptive surface and can help new paint blend and flow.
It is not a varnish and not a substitute for a final varnish. It is a working step used during painting, or occasionally before varnishing, to even out the surface.
Why Oil Paint Sinks In
Oil paint is a mix of pigment and oil binder. When you paint on an absorbent surface, such as an under-primed canvas or a thin underpainting that soaked up oil from the layer above, the paint loses some of its binder and dries matte. Different pigments also absorb different amounts of oil, so some colors sink more than others. Heavy use of solvent to thin the paint leaves less binder behind and increases dullness.
The result is an uneven surface, with some areas glossy and others flat. Oiling out evens those differences and restores the colors you intended.
When to Oil Out
| Situation | Oil out? | Notes |
|---|---|---|
| Dull, sunken patches while painting | Yes | Helps you judge color before continuing |
| Before painting wet-on-dry over a dried layer | Often | Improves blending and brings back saturation |
| Before final varnish | Sometimes | Only if the painting is dry enough; follow varnishing guidelines |
| Painting still wet | No | You risk lifting or muddying the paint |
| Thick impasto | Use caution | The thick paint remains soft inside for a long time |
| Painting with a lean underlayer and fat layer on top | Not needed | The fat-over-lean sequence usually avoids sinking in |
Materials You Need
- Oiling-out medium. Options include a commercially made oiling-out or retouching medium, refined linseed oil, or a diluted blend of oil and solvent. Manufacturers make products labeled for this purpose.
- Soft, lint-free cloths. Cotton rags, old t-shirt material or lint-free paper towels.
- Soft brush (optional). A wide, soft brush for application, kept clean.
- Odorless mineral spirits or a mild solvent if your chosen medium recommends dilution.
- Gloves and good ventilation.
- Drop cloth or table cover.
Read the label on whichever medium you use, because formulas vary. Some contain driers or varnish resins, which affect how they behave.
Step-by-Step: How to Oil Out an Oil Painting
- Check the dryness. The paint should be touch-dry and not tacky. Thick areas may still be soft below the surface, so be gentle.
- Dust the surface. Wipe lightly with a soft, dry cloth or brush to remove dust and debris.
- Prepare a small amount of medium. Pour a little onto a clean rag, not directly on the painting. Less is better.
- Apply a thin film. Rub the medium into the dull areas in small circles, spreading it very thinly. It should look slightly damp but not wet or shiny.
- Buff off the excess. Use a clean, dry cloth to wipe the surface until it only feels slightly slick. Surplus oil left on the surface can become tacky or yellow.
- Check in good light. Look at the painting from an angle. Sunken areas should now look consistent with the rest.
- Paint into it if desired. You can work the next layer into the thin film while it is still slightly receptive. Paint over it according to the fat-over-lean rule.
- Allow to dry. Oiling out slows drying slightly, so wait until the painting is thoroughly dry before varnishing.
Oiling Out vs. Retouch Varnish
| Feature | Oiling out | Retouch varnish |
|---|---|---|
| Composition | Oil or oil-based medium | Thin spray or liquid varnish |
| Main purpose | Restore wet look, improve adhesion | Temporarily saturate dull spots, provide a surface for further work |
| Application | Rubbed in and buffed off | Sprayed or brushed in thin coats |
| Risk | Yellowing or tackiness if too thick | Can interfere with later layers if misused |
| Permanence | Becomes part of the paint film | Thin, temporary; final varnish comes later |
Many painters choose one or the other depending on the stage of the painting and their preference. Follow the manufacturer’s guidance for whichever you use.
Choosing the Right Oil or Medium
Refined linseed oil
A traditional choice. It dries well and forms a strong film. Applied sparingly, it enriches colors, but heavy application can yellow over time, especially in dim environments.
Commercial oiling-out mediums
These are formulated for the job and may include resins or driers. They are convenient and consistent, and many are designed to resist yellowing. Choose a product intended for oil painting and compatible with your paints.
Safflower and poppy oils
Often marketed for lighter colors because they yellow less, though they dry more slowly and can form a less durable film than linseed. Use them thinly and allow plenty of drying time.
Diluted solvent and oil mixes
A little solvent can help the oil spread more thinly. Too much dilutes the oil’s binding effect. Use odorless mineral spirits in small proportion and follow the label of your chosen medium.
Oiling Out and the Fat-Over-Lean Rule
Oil painters follow the “fat over lean” principle: each layer should contain at least as much oil as the layer below it, so lower layers dry first and the surface does not crack. Oiling out adds oil, which is consistent with the rule, but if you apply a thick film of oil and then paint a lean layer on top, you reverse the sequence and risk problems. Keep the oiled film thin, buff it off and apply paint with equal or higher oil content afterward.
Which Painting Stages Benefit Most
During the underpainting and blocking-in stage
Lean layers are the ones most prone to sinking in, since they hold the least oil and often sit on an absorbent ground. If you come back to an underpainting after it has dried and everything looks flat and washed out, a light oiling out lets you see true values before adding the next layer. Judging colors on a dull surface leads to overcorrecting, so this step often saves a lot of frustration.
In the middle of a multi-layer painting
After one session, dry patches can appear next to fresh glossy ones. Oiling out the dull areas before the next session helps new paint blend without leaving visible edges where old and new layers meet. Many portrait and landscape painters do this routinely when they resume work after a pause of several days.
At the finishing stage
Final touches such as highlights and glazes go on more predictably over an even surface. A thin oiled film makes glazes spread smoothly and look more luminous, but resist the temptation to keep adding oil to fix every uneven spot. If the unevenness remains after the painting is completely dry, a proper varnish layer is the right way to unify it.
How Long to Wait Between Oiling Out and Painting
There is no single answer, because conditions matter. A very thin, well-buffed film can be painted into right away while it is slightly receptive, and many artists work this way. If you applied more oil than intended, wait until the surface is no longer tacky, which can take a day or more, depending on the oil, temperature and airflow. If you are unsure, press a clean finger lightly in a corner of the painting: a surface that leaves a sticky print needs more time.
Testing on a Practice Panel
The safest way to learn is to run a small experiment before touching a painting you care about.
- Paint a stripe of dark color and a stripe of light color on a small primed panel, thinned with solvent so they dry matte.
- Let the panel dry until it is touch-dry.
- Divide it in half with painter’s tape. Oil out one half and leave the other untouched.
- Compare the two sides. Note how much richer the treated half looks and how long it takes to settle.
- Paint a test layer over both halves and watch how the paint flows differently on each.
This gives you direct experience with how your chosen medium behaves, including how much to apply and how long it stays receptive, without any risk to real work.
Common Mistakes
- Applying too much oil. A thick film can stay tacky for a long time and may yellow or wrinkle.
- Oiling out wet paint. It lifts and smears color. Wait until the surface is touch-dry.
- Skipping the buffing step. The excess is the problem; remove it.
- Using the wrong oil for the job. Cooking oils and household oils do not dry properly and should never be used.
- Oiling out then varnishing too soon. Give the painting plenty of time to dry thoroughly before varnishing. Traditional guidance suggests months for thick paintings.
- Using greasy rags. A dirty rag transfers dust and old oil to the painting.
- Not testing first. Try the technique on a small corner or a practice panel.
Safety Notes
- Rags soaked in drying oils can heat up and ignite spontaneously as the oil oxidizes. Spread used rags flat to dry outdoors, or store them in a sealed metal container filled with water, and follow local fire guidance.
- Work with good ventilation, especially if you use solvents.
- Wear gloves if you have sensitive skin.
- Keep oils and solvents away from heat and flames.
- Store materials in labeled containers out of reach of children and pets.
Oiling Out in the Context of Varnishing
If you are preparing to varnish, you may notice sunken areas that make the surface look uneven. Some painters oil out these patches before varnishing. Others wait until the painting is dry enough for a proper varnish, which will naturally unify the sheen. Because the painting must be thoroughly dry before final varnish (often at least six months for typical thickness), a thin oiling out may be applied earlier if needed. Check the guidance for your varnish and consider consulting an experienced painter if the work is valuable.
Surface choice also affects how paint sinks in. Absorbent grounds drink up oil faster, and this is one of the factors discussed in the comparison of painting on wood vs. canvas, since wood panels can be sealed to behave differently from canvas.
Preventing Sinking In
- Use a well-sealed, properly primed surface so the ground does not steal oil from the paint.
- Avoid over-thinning with solvent. Keep enough binder in the mixture.
- Apply fat over lean layers consistently.
- Use mediums that add oil rather than only thinning.
- Choose pigments with lower oil absorption for the underpainting where possible.
- Let underlayers dry adequately before overpainting.
FAQs
How do you oil out an oil painting?
When the paint is touch-dry, rub a very thin film of a suitable oiling-out medium onto the surface with a lint-free cloth, then buff off almost all of it. Let the painting dry before further layers or varnish.
What do you use to oil out a painting?
A commercial oiling-out medium, refined linseed oil or a thin blend of oil and a little solvent. Avoid cooking oils and any product not made for oil painting.
Why does oil paint look dull after it dries?
Absorbent grounds or layers can draw oil from the paint, leaving a matte, sunken-in surface. Oiling out restores the saturation temporarily.
Is oiling out the same as varnishing?
No. Oiling out is a thin working layer that becomes part of the paint film. Varnish is a protective final coat applied after the painting is fully dry.
Can you paint on top after oiling out?
Yes, if the film is thin and buffed. Use paint with at least as much oil as the layer beneath, and wait if the surface feels tacky.
Does oiling out make paint yellow?
Too much oil can cause yellowing, particularly with linseed oil in low light. Thin, buffed applications and appropriate oils reduce the risk.
Final Thoughts
Oiling out is a small step that solves a common oil painting problem: dull, sunken patches that hide the real color. Keep the film thin, buff it well and let the painting dry thoroughly before the next stage. Done carefully, it helps you judge colors accurately and keeps layers working together.
For more on how finished oil paintings are presented and bought, explore this overview of oil paintings on canvas and see what buyers look for in a finished surface.
