Oil paint might seem complex, but at its core, it's a simple partnership between two main ingredients: pigment and a binder. Think of it like making a sauce. You have the flavorful ingredients (the pigment) and the liquid base that holds everything together and gives it body (the binder).

Every other ingredient is secondary, added to tweak how the paint behaves. But without pigment and a binder, you don't have paint. You just have colored dust and a bit of oil. Together, they create a versatile and enduring medium that has been a favorite of artists for centuries.

The color in oil paint comes from pigment. These are not dyes, which dissolve in a liquid. Instead, pigments are fine powders of solid material suspended in the oil. They are what give a paint its specific hue, its transparency or opacity, and even its texture.

Historically, pigments came from all sorts of natural sources. Lapis lazuli, a semi-precious stone, was ground down to create a brilliant ultramarine blue. The cochineal insect provided a deep crimson red. Earthy tones like burnt sienna and raw umber came from clays and minerals found in the ground.

Today, while many traditional pigments are still used, chemists have developed synthetic versions that are often more stable, less toxic, and more consistent in color. But the principle remains the same: a colored powder is the starting point for every tube of paint.

Pigment on its own is just dust. To turn it into paint, it needs a binder. The binder is the liquid vehicle that surrounds the pigment particles, allowing them to be brushed onto a surface. It also acts as the glue, hardening over time to lock the pigments in place.

For oil paint, the classic binder is linseed oil. Pressed from the seeds of the flax plant, linseed oil is a type of "drying oil." This is a crucial property. Unlike water, which simply evaporates, linseed oil dries through a chemical reaction with oxygen in the air called oxidation. This process forms a tough, solid, and stable film. This is why oil paintings can take days, weeks, or even months to become fully dry to the touch. The oil isn't disappearing; it's transforming from a liquid into a solid polymer.

Other oils like poppy, walnut, and safflower oil are also used as binders, each with slightly different characteristics. Some are less prone to yellowing over time, while others might dry faster or slower. But linseed oil remains the most common and traditional choice due to its strength and flexibility.

While pigment and binder are the essential duo, a third component often joins the party: the solvent. A solvent is a liquid that can dissolve other substances. In oil painting, solvents like turpentine or mineral spirits are used to thin the paint, making it more fluid and easier to apply.

A painter might add a solvent to their paint to create thin washes of color, similar to watercolor techniques, or to clean their brushes. During the paint fabrication process, a small amount of solvent might be added to adjust the consistency of the paint right in the tube. Unlike the binder, the solvent does evaporate, leaving only the pigment and hardened oil behind on the canvas.

Time to test what you've learned about the building blocks of oil paint.

Understanding these three core components—pigment, binder, and solvent—is the first step toward understanding how oil paint works and how you can make your own.