Oil Painting Mediums: What Each One Does to the Paint, and to What You Inherit

♦ ♦ ♦ JUNE 22, 2026 | 4 MIN READ Oil Painting Mediums: What Each One Does to the Paint, and to What You Inherit At a Glance Oil painting mediums adjust how oil paint flows, dries, and shines. Knowing what each one does tells you how the surface will behave for years, which is the part a buyer actually lives with. There is a small dish on most oil painters’ benches with a clear, faintly amber puddle in it. Sometimes it smells of pine or petroleum, sometimes of nothing at all. That puddle is the medium, and it is doing more to the finished painting than almost anyone looking at the wall realizes. A medium is whatever you add to oil paint straight from the tube to change how it behaves. The pigment and the oil binder are already a complete paint on their own. The medium tunes it. What an oil painting medium actually does Three jobs, really. It thins the paint so it flows. It changes how fast the paint dries. And it changes the final surface, more gloss or more matte, more transparent or more solid. Most mediums do two or three of these at once, which is why painters argue about them. Choosing a medium is choosing a handful of trade-offs. The binder in oil paint is a drying oil, usually linseed. Left alone, tube paint is stiff and slow. A medium loosens that, or speeds it, or makes it glassy. Nothing added is free. Every one of them shifts the chemistry of the film that has to hold for a century. The main oil painting mediums, and what each one changes Start with the drying oils themselves. Linseed oil flows and glosses and dries reasonably fast, but it yellows the most over time. Stand oil, which is linseed cooked thick, levels brushmarks into an enamel smoothness and yellows less, though it dries slowly and stays flexible, which suits upper layers. Walnut and poppy oils yellow least, so painters reach for them in whites and pale blues and accept that they dry slower and weaker. Then solvents. Gamsol, turpentine, odorless mineral spirits. These are not mediums in the strict sense; they thin the paint and evaporate, leaving less binder behind, not more. They belong in the first lean layers, used sparingly, because paint thinned to nothing but pigment and solvent has little holding it to the canvas. Then the alkyds, the modern workhorses. Liquin and Gamblin’s Galkyd family are alkyd resin, a polymerized oil, cut with solvent. They speed drying hard, raise gloss, and increase transparency, which is why glazing painters reach for them. Gamblin’s published figures put a thin Galkyd layer touch-dry in about a day. One of its gels, by the company’s own description, “remains workable for hours and dries within 4-5 days to a shimmery finish.” For a glazing medium for oil painting , that fast, clear, glossy behavior is the entire appeal. Then cold wax, in the other direction entirely. Beeswax paste cut into the paint kills the gloss, scatters the light, and bulks the paint into a body you can carve. It makes matte where the alkyds make shine. The medium is th