ELI5: What Is Oil Painting?

Oil painting is a way of making art using colorful paints that are mixed with special plant oils instead of water.

Imagine you are in the kitchen making frosting for a cake. If you mix food coloring with water, it is thin, runny, and dries up really fast. But if you mix that color with butter, it becomes thick, creamy, and smooth. Oil paint is just like that colorful butter, made by mixing crushed colored powders called pigments with natural oils, usually from flax seeds.

Because oil and water do not mix, painting with oils is very different from using the regular watercolor paints you might use at school. Here is how it works in everyday terms:

• It dries super slowly: If you spill water on the counter, it dries in minutes, but cooking oil stays wet for a long time. Because oil paint stays wet for days or even weeks, artists do not have to rush. They can blend colors together smoothly, like smearing peanut butter and jelly together on bread, to make soft shadows and glowing skin.
• It is thick and textured: Artists can spread the paint thinly like syrup, or pile it on thick like frosting using a brush or a tiny spatula. If you touch an old oil painting, you can often feel the rough, bumpy ridges left behind.
• It lasts a very long time: Once the oil finally hardens, it turns into a tough, shiny layer, almost like a plastic shield. That is why famous oil paintings in museums, like the Mona Lisa, can last for hundreds of years without the colors fading away.