Oil painting mediums sit in the category of decisions that seem academic until they suddenly matter. The choice between linseed, walnut, safflower, and poppy oils affects how fast your paint dries, how the surface looks after 10 years, how slick the brush feels in your hand, and how the final painting reads under museum lighting. This guide focuses on the two most common in 2026, refined linseed and walnut, and explains where each one is the right tool.
What an oil medium actually does
When you squeeze oil paint from a tube, it is already mixed with a drying oil at the factory (almost always linseed, sometimes safflower or poppy). That tube paint has a specific consistency, oil-to-pigment ratio, and drying speed. The medium you add at the easel changes those properties. You add medium to:
- Thin the paint without using solvent (preserves the paint film integrity)
- Slow or speed drying time
- Adjust gloss versus matte finish
- Improve flow for thin glazes and detail work
- Reduce yellowing in light passages
- Increase film flexibility for canvas paintings
There is no rule requiring you to add medium. Many painters work entirely from the tube. But once you start layering or glazing, controlling the oil added per layer becomes important for archival quality.
Linseed in detail
Linseed oil is pressed from flax seeds and has been the dominant oil painting medium since the 15th century. Modern refined linseed for painting is processed to remove the mucilage and free fatty acids that cause unpredictable drying.
Drying time: A thin film of refined linseed is touch-dry in 2 to 4 days, fully cured in 6 to 12 months. Hot weather and direct sun cut these times in half. Cold studios double them.
Yellowing: Refined linseed yellows by 8 to 12 percent (measured by reflectance) over the first 5 years, then more slowly. Visible in pale whites and pastel skies. Cold-pressed linseed yellows slightly more than refined. Bleached linseed yellows less but loses some film strength.
Film strength: Linseed produces the strongest, most flexible film of the common oils. Less likely to crack on flexible canvas over decades.
Brush feel: Buttery, slightly viscous. Predictable.
Price: Around $14 for 500 ml of Winsor and Newton refined linseed in May 2026. Premium options (Williamsburg, M. Graham) run $22 to $28 for 500 ml.
Walnut in detail
Walnut oil is pressed from walnut kernels. It was used by some 15th and 16th century Italian and Flemish painters (Leonardo and Van Eyck both worked with walnut) but fell out of common use until M. Graham and other modern brands brought it back in the 2000s.
Drying time: A thin film is touch-dry in 4 to 8 days, fully cured in 8 to 14 months. Significantly slower than linseed.
Yellowing: Cold-pressed walnut yellows by 3 to 6 percent over 5 years, roughly half the rate of linseed. The difference becomes visible in whites within a decade.
Film strength: Slightly softer film than linseed. Adequate for canvas paintings but less ideal for very large or stretched-canvas work that flexes.
Brush feel: Silkier and slightly thinner than linseed. Some painters describe it as “moving like cream.”
Price: Around $22 for 350 ml of M. Graham walnut oil in May 2026. Significantly more expensive per milliliter than linseed.
Where each one wins
Linseed wins for:
- Underpainting and lower layers where drying speed matters
- Dark colors (earth tones, blacks, deep blues) where yellowing is invisible
- Large canvases that flex and need film strength
- Tight budgets, the price difference is real
- Painters who layer quickly and want each layer touch-dry sooner
Walnut wins for:
- Upper layers and final glazes where yellowing in whites would be visible
- Portraits with pale skin tones
- Sky and cloud work in landscape paintings
- Painters who work slowly over a wet layer for hours
- Small to medium paintings on rigid panels where flex resistance matters less
- Painters with mild solvent sensitivity, walnut has no odor and many use it as a brush-cleaning oil too
Other common mediums in 2026
Safflower oil. Common in tube whites (Winsor and Newton, Gamblin) because it yellows less than linseed. As a medium, it dries slower than linseed but faster than walnut, and produces a softer film. Available from Gamblin around $18 for 250 ml.
Poppy oil. Even less yellowing than safflower or walnut but the slowest-drying and weakest film. Used historically for white and pale colors only. Rarely sold as a standalone medium today.
Stand oil. Linseed oil heat-polymerized in a vacuum. Thick, slow-drying, glossy, very enamel-like. Used in glazing recipes (with damar varnish and turpentine in traditional formulas, or with Gamsol in modern solvent-free recipes). Around $22 for 250 ml.
Sun-thickened linseed. Linseed thickened by sun exposure in shallow trays. More transparent and slightly faster-drying than stand oil. Less common commercially.
Solvent-free gels (Gamblin Solvent-Free Gel, Galkyd Gel). Alkyd-modified linseed oil in a gel consistency. Dry in 1 to 3 days. Useful for painters avoiding solvents entirely. Around $19 per 150 ml tube.
A practical layering recipe
For a standard portrait or landscape on canvas using both oils:
- Layer 1 (drawing and tonal underpainting): Paint from the tube, thinned with Gamsol or a small amount of refined linseed. Let dry 2 to 3 days.
- Layer 2 (block-in of color): Paint plus 1 part refined linseed to 10 parts paint. Let dry 4 to 6 days.
- Layer 3 (developing forms): Paint plus 1 part walnut oil to 8 parts paint. Let dry 5 to 8 days.
- Layer 4 (highlights and final whites): Paint plus 1 part walnut to 6 parts paint, with a few drops of cold-pressed walnut for the brightest whites.
This pattern keeps each upper layer slightly fatter (more oil) than the one below it (fat-over-lean), uses linseed where strength and dry-time matter and walnut where yellowing matters. There is nothing magic about this exact ratio, but the principle of slow over fast and fat over lean is universal.
What to buy first
If you are picking one oil to start with, buy refined linseed. It is cheaper, drier-faster, available everywhere, and the medium most painting instruction is written around. Add walnut once you are confident in your workflow and start to care about yellowing in whites.
For everything else around oil painting from medium safety to brushes to the choice between oil and acrylic, our oil paint vs acrylic for beginners guide covers the broader picture. For mixed-media work, the gouache vs watercolor vs acrylic comparison sits next to this article in the painting-mediums series.
Frequently asked questions
Does walnut oil really yellow less than linseed?+
Yes, and the difference is visible over years. Cold-pressed walnut oil yellows by roughly 30 to 50 percent less than refined linseed oil over a decade in normal indoor light. This matters most in whites, light blues, and pale flesh tones where any yellowing becomes obvious. For dark colors and earth tones, the difference is barely noticeable and linseed's faster drying often wins out.
Which oil dries faster, linseed or walnut?+
Linseed dries roughly 1.5 to 2 times faster than walnut at the same film thickness. A thin glaze of linseed is touch-dry in 2 to 4 days; the same glaze in walnut needs 4 to 8 days. For painters who work in long sessions over a wet layer, walnut's slower drying is a feature. For painters who layer quickly, linseed wins.
Will walnut oil really go rancid the way the internet says?+
Refined walnut oil for painting (M. Graham, Roberson) is processed to remove the free fatty acids that cause rancidity, and stores for 1 to 2 years sealed in a cool place. Culinary walnut oil from a grocery store will go rancid faster (3 to 6 months) and is not chemically the same product. Use only oil specifically sold for painting, not cooking oil, no matter how cost-tempting.
Can I mix linseed and walnut oils in the same painting?+
Yes. Fat-over-lean rules still apply, the upper layers must contain more oil than the lower layers regardless of which oil. Some painters use linseed in underpainting for fast drying, then switch to walnut in upper layers for slower blending and less yellowing in highlight whites. Just be consistent within a single layer.
Are stand oil, sun-thickened linseed, and refined linseed the same thing?+
No. Refined linseed is filtered raw linseed oil, the most common and the cheapest at around $14 per 500 ml. Stand oil is linseed heated under vacuum until it polymerizes, producing a thicker, slower-drying oil with a glossier finish ($22 per 250 ml). Sun-thickened linseed is partially bleached and thickened by sun exposure, more transparent and faster-drying than stand oil. They are different tools, not substitutes.
Morgan Davis
Morgan Davis writes for The Tested Hub.