Quick answer: Mediums of painting are the different kinds of paint artists work with, defined mainly by the binder that holds the pigment: oil, acrylic, watercolor, gouache, egg tempera, encaustic, fresco, casein and others. The word “medium” also has a second, narrower meaning: a liquid or gel you add to paint, such as linseed oil or glazing medium, to change how it flows, dries or shines. Both meanings come back to the same idea, which is the substance that carries color onto a surface.
If you have ever wondered what are mediums of painting, you have probably noticed the term used in two ways that do not quite match. A gallery label might say “Medium: oil on canvas,” while a supply shop sells a bottle labeled “painting medium.” One describes the type of paint; the other is an additive. Untangling those two meanings makes both art history and art-supply shopping much easier.
This explainer starts with a clear definition, walks through the major painting mediums and how they differ, and then covers additive mediums, with a focus on oil. For detail on specific oil additives, our guide to oil painting mediums goes product type by product type.
What “Medium” Means in Painting
In the broadest sense, a medium is the material an artist uses to make a work. Sculptors work in bronze or marble; photographers work in film or digital files. In painting, the medium is the paint itself, and every paint has the same basic structure:
- Pigment: finely ground colored particles, from minerals, synthetic compounds or, historically, plants and insects.
- Binder: the substance that sticks the pigment particles together and to the surface. This is what defines the medium.
- Vehicle or diluent: what thins the paint for application, such as water or solvent.
- Additives: stabilizers, fillers, driers or preservatives, depending on the paint.
Change the binder and you change almost everything: drying time, flexibility, transparency, surface sheen, how long the painting lasts and what surfaces it can go on. That is why painting mediums are named after their binders.
Is Paint a Medium?
Yes. In the sense of an artistic medium, paint is the medium, and each type of paint is its own medium. When a museum lists “oil on canvas,” “oil” is the medium and “canvas” is the support. The confusion comes from the second meaning, where “medium” refers to an additive. A bottle of glazing medium is not a paint on its own, because it contains no pigment, but it becomes part of the paint film once mixed in.
A simple way to keep them straight: the painting medium is what the artwork is made of; a paint medium or additive medium is something you mix into paint.
The Major Mediums of Painting
Oil paint
Binder: drying oils, mainly linseed, plus safflower, walnut or poppy.
Oil paint dries slowly by reacting with oxygen, which gives artists hours or days to blend and adjust. It produces deep, saturated color and can be applied in thin transparent glazes or thick impasto. It became the dominant medium in European painting from around the fifteenth century onward and is still the standard for many realist and traditional painters. Cleanup traditionally uses solvents, though water-mixable oils exist.
Acrylic paint
Binder: acrylic polymer emulsion.
Acrylic arrived in the mid-twentieth century. It thins with water, dries in minutes as the water evaporates, and forms a flexible, water-resistant film once dry. That speed suits layering and mixed media but makes soft blending harder. Acrylic can mimic watercolor when thinned or oil-like body when used thick, and it works on canvas, paper, wood and many other surfaces.
Watercolor
Binder: gum arabic, a natural plant gum.
Watercolor is transparent and relies on the white of the paper to create light. It stays rewettable after drying, so layers can be lifted or softened. It is portable and fast, popular for sketching and illustration, but it is unforgiving: covering mistakes with lighter colors is difficult.
Gouache
Binder: gum arabic, with more pigment and often an opaque filler.
Gouache is essentially opaque watercolor. It dries to a flat, matte finish and can cover darker colors with lighter ones. Designers and illustrators have used it for generations. Like watercolor, it reactivates with water. Acrylic gouache is a related product that dries water-resistant.
Egg tempera
Binder: egg yolk.
Before oil, egg tempera was the main medium for panel painting in medieval and early Renaissance Europe. It dries quickly to a satin surface and is built up with fine hatched strokes rather than blended. Tempera is usually painted on rigid gesso panels, since it can crack on flexible canvas.
Encaustic
Binder: beeswax, often with damar resin.
Encaustic is painted hot. The wax is melted, mixed with pigment and applied with brushes or tools, then fused with heat. Ancient Egyptian funerary portraits were made this way, and the medium has a strong contemporary following for its luminous, textured surfaces.
Fresco
Binder: lime plaster itself.
In true fresco, pigment mixed with water is painted onto wet lime plaster. As the plaster cures, the color becomes locked into the wall. It is a mural medium that requires working in sections, each completed while the plaster is still wet.
Casein
Binder: milk protein.
Casein paint dries quickly to a matte, slightly velvety finish and becomes fairly water-resistant over time. It was popular with illustrators before acrylics and is still used by some painters for underpaintings and studies.
Alkyd paint
Binder: oil-modified alkyd resin.
Alkyd colors handle much like oils but dry noticeably faster, often overnight in thin layers. They can be mixed with traditional oils, and alkyd resins are also the basis of many fast-drying oil painting mediums.
Other mediums
Ink, spray paint, enamel, oil pastel, soft pastel and digital painting are also called painting mediums in many contexts, though pastels are often classed as drawing media because they are applied dry.
Painting Mediums Compared
| Medium | Binder | Drying | Finish | Thins with | Typical support |
|---|---|---|---|---|---|
| Oil | Drying oil | Slow (days to touch-dry, longer to cure) | Satin to glossy | Solvent or oil | Canvas, panel, oil paper |
| Acrylic | Acrylic polymer | Fast (minutes) | Satin to glossy | Water | Canvas, paper, wood, many surfaces |
| Watercolor | Gum arabic | Fast; rewettable | Matte, transparent | Water | Watercolor paper |
| Gouache | Gum arabic | Fast; rewettable | Matte, opaque | Water | Paper, illustration board |
| Egg tempera | Egg yolk | Very fast | Satin | Water | Rigid gesso panel |
| Encaustic | Wax and resin | Sets as it cools | Luminous, can be buffed | Heat | Rigid absorbent panel |
| Fresco | Lime plaster | Cures with plaster | Matte | Water | Plaster wall |
| Casein | Milk protein | Fast | Matte | Water | Rigid panel, board |
The Second Meaning: Additive Mediums
Within any one type of paint, a “medium” is also a product you add to change the paint’s behavior without adding color. Every major paint type has its own range.
Oil painting mediums
- Solvents such as odorless mineral spirits thin paint for early layers.
- Refined or cold-pressed linseed oil adds flow and gloss.
- Stand oil is a thickened oil that levels brushstrokes and suits glazing.
- Alkyd mediums speed drying and help transparent glazes.
- Impasto and wax mediums thicken paint and hold texture.
These additives are central to the fat-over-lean principle, where early layers contain less oil than later ones to prevent cracking. If you want to see how these products differ in practice, the comparison of top oil mediums and their uses is a good next read.
Acrylic mediums
Acrylic additives are mostly the same polymer as the paint without pigment. Gloss, matte and satin mediums change sheen; gel mediums add body; retarders slow drying; flow improvers help paint level; texture pastes build relief. Because they share the paint’s binder, most can be added in large amounts without weakening the film.
Watercolor and gouache mediums
Gum arabic adds gloss and transparency; ox gall improves flow; granulation medium encourages a speckled texture; masking fluid temporarily protects paper from paint.
How to Choose a Painting Medium
No medium is objectively best. Each suits certain goals, spaces and temperaments.
| If you want… | Consider |
|---|---|
| Long blending time and rich color | Oil |
| Quick drying and easy water cleanup | Acrylic |
| Portable sketching and luminous washes | Watercolor |
| Flat, opaque, design-friendly color | Gouache |
| Fine detail and historical technique | Egg tempera |
| Sculptural, layered, glowing surfaces | Encaustic |
| Oil handling with faster drying | Alkyd |
Practical factors matter as much as look. Oil needs ventilation for solvents and patience for drying. Encaustic needs heat tools. Acrylic and watercolor suit small spaces and households with kids. Many painters work in two or more mediums, using acrylic or watercolor for studies and oil for finished pieces.
A Short Timeline of Painting Mediums
Painting mediums did not appear all at once. Each new binder solved a problem the previous ones had, and older mediums often survived alongside the new.
- Prehistoric pigments: cave painters used earth pigments and charcoal, likely bound with water, animal fat or plant matter, though exact recipes are debated.
- Ancient fresco and encaustic: Mediterranean cultures painted walls in lime plaster and portraits in hot wax.
- Medieval egg tempera: panel painters in Europe relied on egg yolk for altarpieces and icons.
- Renaissance oil: drying oils, used earlier for decoration, were refined into a fine-art medium by Northern European painters and spread across Europe, eventually replacing tempera for most easel painting.
- Industrial-era watercolor and gouache: ready-made cakes and tubes made water-based color portable for travelers and illustrators.
- Twentieth-century synthetics: acrylic and alkyd binders gave artists fast-drying alternatives with new working properties.
Knowing this history helps when reading about older paintings. A medieval panel that looks finely hatched is probably tempera, while the soft blended transitions of a later portrait reflect oil’s long working time.
Medium and Support: How They Work Together
A painting medium is only half the picture; the support it sits on matters too. Flexible supports like stretched canvas suit mediums that stay somewhat flexible, such as oil and acrylic. Brittle mediums like egg tempera and encaustic need rigid panels, because flexing would crack them. Water-based mediums like watercolor need absorbent paper designed to take repeated wetting without falling apart. Fresco is the extreme case, where the wall and the binder are effectively the same material. Matching medium and support is one of the first decisions that determines how well a painting survives.
Why the Binder Matters for Longevity
The binder decides how a painting ages. Oil films become harder and less flexible over decades, which is why layering rules matter. Acrylic stays relatively flexible but can attract dust if left unvarnished. Watercolor and gouache are only as durable as the paper beneath them and need protection from light and moisture. Fresco can last centuries on a stable wall. Understanding the medium helps you choose supports, varnishes and storage that protect the work.
Mixing Mediums
Some combinations work; others fail.
- Oil over acrylic: widely used. Dry acrylic makes a sound underpainting.
- Acrylic over oil: not recommended. Acrylic does not bond reliably to an oily surface.
- Watercolor with gouache: common and compatible, since both use gum arabic.
- Oil with alkyd: compatible; alkyds can speed up oil layers.
- Mixed media: acrylic works well with collage, ink and pastel. Oil-based materials go on top of water-based ones, not the reverse.
FAQs
What are the main mediums of painting?
The most common are oil, acrylic, watercolor and gouache. Egg tempera, encaustic, fresco, casein and alkyd are also important painting mediums with long or specialized histories.
Is paint a medium?
Yes. Each type of paint, such as oil or acrylic, is an artistic medium. The word is also used for additives, like linseed oil or gel medium, that change how paint behaves.
What is the difference between a medium and a binder?
The binder is the ingredient that holds pigment together, such as linseed oil or egg yolk. The medium is the whole paint type named after that binder, or an additive mixed into paint.
What is the easiest painting medium for beginners?
Acrylic is often considered the easiest to start with because it uses water, dries quickly and works on many surfaces. Watercolor is portable but harder to correct.
Why do oil painters use mediums?
To adjust consistency, drying time, transparency and sheen, and to follow fat over lean when building layers.
Is drawing a painting medium?
Drawing media such as graphite and charcoal are usually classed separately. Pastels sit in between and are sometimes called painting mediums because of how they are used.
Next Step
Understanding painting mediums gives you a map: the binder sets the rules, and additive mediums let you bend them. If oil is the medium you are exploring, take a look at our breakdown of the best oil painting mediums explained to choose additives for glazing, faster drying or texture.
